BIBLIOGRAPHY BINAY-AN, PETER C. APRIL ...
BIBLIOGRAPHY
BINAY-AN, PETER C. APRIL 2008. The Insect Pests of Sweet Corn, Sugar 75 (Zea
maize Saccharata) at La Trinidad, Benguet. Benguet State University, La Trinidad, Benguet.
Adviser: Eulogio V. Cardona Jr., PhD.
ABSTRACT
The study aims to know the insects and other related pests of sweet corn variety sugar 75,
record the degree of injury caused by the insect pests and classify the insets according to
economic importance.
In the roots of sweet corn, there were no insects noted damaging based on the results of
this research. On the other hand, literature indicates that the insects damaging on roots are white
grubs, root webworm, cutworm and wireworm. The insects recorded damaging on the stem of
corn were corn borer, variegated cutworm, cluster caterpillar and aphids. The recorded most
destructive was corn borer. In the corn leaves, the insects recorded damaging were corn borer,
variegated cutworm, cluster caterpillar, semi-looper, armyworm, corn earworm, tussock moth
with genus of Euproctis sp. and Dasychira sp., aphids, jassid, long horned grasshopper, Katydid,
snout beetle, cockchafer, leaf beetle, western corn rootworm, northern corn rootworm, snail and
slugs. Among the insects recorded, the most destructive were variegated cutworm, cluster
caterpillar, armyworm and aphids. On the corn ear, the insects observed damaging were corn
earworm, corn borer, and aphids. The most destructive was corn earworm. In the tassel, the
insects damaging were corn borer, corn earworm and aphids. Aphids and corn borer were the
two most destructive.
The most destructive pest of sweet corn sugar 75 was corn borer. This insect causes
damage in corn to as high as 76 to 100%. Corn borer was followed by variegated cutworm,
armyworm, cluster caterpillar, corn earworm and aphids with the degree of damage of 26 to
50%. The jassid, snout beetle, cockchafer, leaf beetle, western corn rootworm, northern corn
rootworm, long horned grasshopper, katydid, snail and slugs cause damage in corn from 1 to
25%.
TABLE OF CONTENTS
Page
Bibliography………………………………………………..…………….. i
Abstract…………………………………………………………………....
i
Table of Contents ………………………………………………………… iii
INTRODUCTION…………………………………………..…….……….
1
REVIEW OF LITERATURE….…………………………………………. 3
METHODOLOGY…………….…………………………………………. 6
RESULTS AND DISCUSSION
Insects and Related Pest Attacking
Sweet Corn 75 …………………………………………………….. 8
Classification of the Pest Associated with
Sweet Corn Sugar 75……………………………………………... 18
Degree of Injury…………………………………………………... 26
Major and Minor Pest Associated with
Sweet Corn Sugar 75...…………………………………………….. 34
SUMMARY, CONCLUSION AND RECOMMENDATION
Summary…………………………………………………………… 37
Conclusion………………………………………………………..... 38
Recommendation………………………………………………….. 39
LITERATURE CITED ………………………………………………..….. 40
INTRODUCTION
Corn, (Zea maize Linnaeus) is a world wide field crop adapted to semi-temperate
and tropical climates. It is an annual crop and belongs to the family graminnae. It is rich
in nutrient elements and serves many importance to human and industrial uses like in the
formulation of feeds for poultry and livestock’s. In the Philippines, corn is planted whole
year round in the provinces of Pangasinan, Isabela, Cagayan, Ilocos Region, Cebu, and
Central Mindanao. In Cebu, corn is the staple food crop of the Cebuano’s.
One variety of corn that attracts the attention of most consumers is the
development of the hybrid green corn. This variety has high demand in the market as
green corn. It is sold in the super market, along the sari-sari store and in public market.
Because of the persistent marketing strategies of the companies, the farmers in Benguet
have learned the planting of sweet corn. Normally, these are noted by strip cropping at
the end of vegetable plots and as for crop rotation. By observation, one of the limiting
factors for the production of green corn is the infestation of insect pests.
Literature indicates that the most destructive insects in corn are corn earworm,
European corn borer, southern corn rootworm, cutworm, white grub, and wireworm. The
underground insect pests normally inhabit the soil while they are injuring the plant. They
usually damage the roots or other subterranean parts of the plants. But some insects may
feed or injure parts of the plants above the soil. The more important soil insects include
cutworm, root aphid, rootworm, white grub, and wireworm. The insect pests on the stalk,
leaf and ear of corn are armyworm, chinch bug, earworm, European corn borer, flea
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beetle, grass hopper, Japanese beetle, leaf aphid, and south western corn borer according
to Thompson and Kelly, (1959).
Identification of the various insect pests and other arthropods attacking corn
would be a great guide for future management to boost the production and quality of
corn. This means that appropriate control measure could only be provided for the sweet
corn sugar 75 should the insect pests be correctly identified.
The study was conducted to know the insects and other related pests feeding on
sweet corn variety sugar 75, record the degree of injury caused by these insect pest on
sweet corn variety sugar 75 and to classify the insets according to economic importance.
The study was conducted at Benguet State University Balili Experimental Area,
La Trinidad, Benguet from December 2007 to February 2008.
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REVIEW OF LITERATURE
Importance of Corn
Corn which is classified as corncobs is an important source of furfural, a liquid
used in manufacturing nylon fibers and phenol-formaldehyde plastics, refining wood
resin, making lubricating oils from petroleum, and purifying butadiene in the production
of synthetic rubber. Ground corncobs are used as a soft-grit abrasive. Large whole cobs
from a special type of corn are used for pipes for smoking tobacco oil, as cooking and
salad oil and as margarine. It is also used in the manufacturing of paints, scups, and
linoleum. The search for alternate source of energy has brought attention to corn as a fuel
source. Corn is processed to produce alcohol for use with gasoline as gasohol. The dry
stalk is potentially important for fuel biomass (Moseman, 2006).
Jugenheimer (1976) cited that corn has many uses; it is used primarily as food for
human in most areas of the world, for livestock feeds where about eighty five (85)
percent of the crop is fed to livestock, industrial uses which may be divided into four
categories; mixed feed manufactures, dry process millers; wet processes, and distilling
and fermentation industries.
Cultural Practices of Corn
Jugenheimer (1976) reported that the corn perform well on well-drained, fertile
soil and in areas with moderately high summer temperatures, warm nights, and adequate
but not excessive rainfall. Similarly, corn prefer-well-aerated deep, warm loams
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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containing abundance of organic matters, nitrogen’s, phosphorous, and potassium. The
amount, distribution, and efficiency of rain fall also are importance factors.
Corn plant has an erect and solid stem. It varies widely in height. Some dwarf
varieties are more than 60 cm or more. The average height of corn is 2.4 m. The leaves
which grow alternately are long and narrow. The main stalk terminates in a staminate
(male) inflorescence. The tassel is made up of many small flowers termed spikelets, and
each spikelet bears tree small anthers, which produce the pollen grains, or male gametes.
The pistellate (female) inflorescence of the ear is a unique structure with up to 1,000
seeds borne on a hard core called the cob. The ear is enclosed in modified leaves called
husk. The individual silk fibers that produce from the tip of the ear are the elongated
styles, each attached to an individual ovary. Pollen from the tassel is carried by the wind
and falls onto the silks, where it germinates and grows down through the silk until it
reaches the ovary. Each fertilized ovary grows and developed into a kernel (Moseman,
2006).
Common Insect Pest Associated with Corn
McCollum and Ware (1980) cited that the principal insects of corn are the corn
earworm, the southern corn stalk borer, and the European corn borer. Mendiola (1958)
stated that the most common insect pest is corn borer, corn earworm and the corn weevil.
Opina et al., (1983) stated that among the serious insect pests of corn, lepidopterous pests
are considered the major constraint in corn production. They attack almost all stages of
plant development. The corn borer (Ostrinia furnacalis Gueene) and corn earworm
(Helicoverpa armigera Hubner) may severely attack young plants and they usually
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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persist up to maturity. Vegetative stage of the crop is usually vulnerable to army worm
(Mythimna separata Walker), cutworm (Spodoptera litura Fabr.) and semi-looper
(Chrysodeixes chalcites Esper).
Other Insects of Corn
Other insects attacking corn are corn leaf aphid (Aphis maidis), maize billbug
(Sphenophorus maidis), corn flea beetle (Chaetocnema pulicaria), desert corn flea beetle
(C. ectypa), larger corn-stalk borer (Diatraea zeacolella), rough-headed corn-stalk beetle
(Euetheda rugiceps), white grub (Phyllophaga species), corn-root webworm or budworm
(Crambus caliginosellus), maize billbug (Calendra maidis), seed-corn maggot (Hylemyia
platora), wireworm, webworm, and the Japanese beetle (Martin et al., 1976).
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METHODOLOGY
An area of about 200 square meters was prepared at the Benguet State University
Balili Experimental Area, La Trinidad, Benguet. The area was cleaned from weeds and
cultivated using grab hoe, shovel, bolo, and other materials. After cleaning and
cultivating the plots, chicken manure was applied. Planting was done on plots with a
dimension of 1x10 meters. All agronomic practices as required by the plants were
provided.
The observation on the insects and arthropods associated damaging the crop was
done upon the germination of the plants until harvesting. Observation was fixed at
weekly interval until harvest. Collected insects and other related pests were brought in the
laboratory and were identified. The taxonomic hierarchy: order, family, genus, species,
common name was the basis for identification. Entomology related books, internet, and
other references were used as reference materials. The insects infesting the roots were
evaluated when the ears were harvested. Fifty corn plants were uprooted in the roots were
scrutinized for the presence of insects.
Monitoring the degree of injury by the pest insects was determined through
percentage by visual estimation of the whole plant. For example, the sample plants were
rated by visual observation using the following index:
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ORDER/COMMON RATING QUALITATIVE
DESCRIPTION
NAME
INDEX
INDEX
1
No damage
No injury
3
Slightly damage
1 to 25 % damage on plant
5
Moderately damage
26 to 50% damage on plant
7
Severely damage
51 to 75% damage on plant
9
Very severely damage
76 to 100% damage on plant
Insect’s degree of damage of above 51% was considered major pest and minor
pest for those insects with a level of injury of below 50%.
Data Gathered:
1.
Various insects damaging on sugar 75. The insects and other related pests
collected were identified by using entomology related books, internet and other
references.
2.
Degree of injury. The degree of injury in percent (%) by the insects on
sweet corn 75 were assessed.
3.
Major and minor pest. The insect pests that has the degree of injury of
51% and above is considered major pests and minor pests for those insects with a degree
of injury of 50% and below.
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RESULTS AND DISCUSSION
Insects and Related Pest Associated Attacking Sweet Corn 75
The details of the various insect pests and non- insect pests associated damaging
on sweet corn sugar 75 are presented in Table 1. The insects are presented according to
the parts of corn they damage. Discussion on the insect’s nature of damage, the stage of
the plant they damage and morphological description of the insects are likewise
presented.
Insects’ attacking the roots. Literature indicates the existence of white grubs, root
webworm, cutworm and wireworm attacking the roots of corn. In these study however,
these insect pests were not encountered.
Insects attacking the stem
a. Corn borer. The larva is the destructive stage while the adults are not
injurious. The larva upon emergence from the egg, feeds on the leaves by
chewing. After few more days or when the larva has reached the 3rd instar,
they transfer to the stem and feed by chewing. They are actively feeding at
night and at daytime. The larva damages the stem by chewing and as a result
the stem is bored. The part of the stem near the developing corn ear is
preferred for damaging. As a result of boring, the stem becomes weak and
blown down when there are strong winds. The larva is present in the corn
damaging during the late vegetative stage until maturity.
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Table 1. Destructive stages and time were they active attacking sweet corn 75
PARTS OF PLANT/
TIME
DESTRUCTIVE
PARTS OF THE PLANT THEY
THEY
STAGE
ATTACK
COMMON NAME
ATTACK
Day Night
Larva Nymph Adult Roots Stem leaves Ear Tassel
Roots*
White grubs
X
X
X
X
Corn-root webworm
X
X
X
X
Corn cutworm
X
X
X
X
X
Wireworm
X
X
X
X
Stem
Corn borer
X
X
X
X
X
X
X
Variegated cutworm
X
X
X
X
X
Cluster caterpillar
X
X
X
X
Aphids
X
X
X
X
X
X
X
Leaves
Corn borer
X
X
X
X
X
X
X
Variegated cutworm
X
X
X
X
X
Semi-looper
X
X
X
Armyworm
X
X
X
X
Cluster caterpillar
X
X
X
X
Tussock moth
X
X
X
X
(Euproctis sp. and
Dasychira sp.)
∗ Insects of the roots of sweet corn were not observed in this study. The insects presented
above were taken from literature.
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Table 1. Continued . . .
PARTS OF PLANT/
TIME
DESTRUCTIVE
PARTS OF THE PLANT THEY
THEY
STAGE
ATTACK
COMMON NAME
ATTACK
Day Night
Larva Nymph Adult Roots Stem leaves Ear Tassel
Woolly bear caterpillar
X
X
X
X
Aphids
X
X
X
X
X
X
X
Jassids
X
X
X
Katydid
X
X
X
Long horned grasshopper X
X
X
Snout beetle
X
X
X
X
Cockchafer
X
X
X
X
X
Leaf beetle
X
X
X
X
Western corn rootworm
X
X
X
X
X
X
Northern corn rootworm
X
X
X
X
X
X
Snail
X
X
X
X
Slug
X
X
X
X
X
Ear
Corn borer
X
X
X
X
X
X
X
Corn earworm
X
X
X
X
X
X
X
Aphids
X
X
X
X
X
X
X
Tassel
Corn borer
X
X
X
X
X
X
X
Corn earworm
X
X
X
X
X
X
X
Aphids
X
X
X
X
X
X
X
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The destructive larva is slender, bluish-green, brown-striped caterpillar up
to 19 mm long (Fig. 1). The adults are small, tan, night fliers about ½ inches
in length that hold their wings in a delta shape when at rest.
b. Variegated cutworm and cluster caterpillar. The larva or the worm stage
damages the stem. The adults are not destructive. The larva cut off the stem of
young corn. Normally, they are destructive to the young and growing corn.
They are active at night time and hide under debris on the soil surface at day
time.
The body of variegated cutworm measures 1 to 1.75 inches in length and
commonly curl into a C-shape when disturbed (Fig. 2). The color is greenish
brown with several longitudinal stripes. The body of cluster caterpillar
measures 1.5 to 2.0 inches long (Fig. 3). The adults or moths are
approximately 1 inch long with a wing span of 1.25 to 2 inches and vary
widely in coloration. The eggs are somewhat flattened on top, white to dull or
off-white in color.
c. Aphids. The nymphs and adults are destructive. Aphids damage by sucking
the juice of the corn stem. The insect was noticed damaging the stem only
during the early vegetative stage.
Insects attacking the leaves
a. Corn borer. Corn borer was noted damaging on the leaves only when the
insects are still small. The larva damage by chewing the leaves. This is soon
after emergence from the eggs. But since the larva is small as they just
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emerged from egg, the damage they normally create on the leaves is very
small to negligible.
b. Variegated cutworm and cluster caterpillar. This worm climbs the stem and
damages the leaves. The larva chews and cut off the leaves of young plants.
They are active at night time. During the day, they hide under debris on the
soil surface. The insect is noticeable in corn only during the early emergence
stage of the plant.
c. Semi-looper. The larva is the destructive stage. The adult is free living while
the larva feeds on underside of the leaves, making windows between the
veins. The leaf area affected is silvery to pale gray in color.
The full grown insect is 25-30 mm long. The body is green with green
stripes along the body (Fig. 4).
d. Armyworm. The larva is the destructive stage while the adult is free living.
The worm feeds initially on the leaf margins. The larva feeds in colonies and
skeletonizes leaves of near vegetative until maturity. The larva feeds singly on
leaves during daytime. They are prevalent during the early emergence until
early vegetative stage.
The young armyworm is pale green. The mature larva is basically
yellowish- or brownish-green with a tan or greenish- brown head mottled with
dark brown. The smooth, practically hairless body is marked with three
longitudinal dark stripes, one along each side and one down the back. A full
grown armyworm is 30 to 35 mm long (Fig. 5). The adult armyworm moth is
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grayish-brown forewings, each with a white spot near the center, and grayish-
white hind wings. The wingspan averages 38.5 mm.
e. Corn earworm. The early stage larva damages the leaves. The larva damage
by chewing the leaves. The insect is prevalent during the late vegetative until
the maturity stage. As noticed, damage on the leaves is small to negligible.
The presence of the insect on the leaves is temporary as the corn ear is the
preferred part for damaging.
The body color of corn earworm is pale green or pinkish to brown. It
measures 1.5 to 1.6 inches long (Fig. 6).
f. Tussock moth (Euproctis sp. and Dasychira sp.) and woolly bear caterpillar.
The larva is the destructive stage while the adult are free living. The larva
feeds by chewing the side parts of the leaves. Feeding is done at daytime.
The young larva measures 1/8 to ¼ inch (4-7 mm) long. They have fine
body hairs which later develop into tufts. Mature larvae measures ¼ inch (3.1
cm) long. They are colorful (Fig. 7 and 8). The body color of woolly bear
caterpillar is brownish to black. It measures 2 1/8 inch (55 mm) long (Fig. 9)
g. Aphids. The nymphs and adults are destructive. Aphid’s damage by sucking
the juice of the corn leaves. The insect were noticed damaging during the
early vegetative until maturity stage. However, they are prevalent during the
flowering stage.
The body of aphids measures 2.0 mm long (Fig. 10). The color is pale
bluish-green with black antennae, legs and cornicles. The head is marked with
two longitudinal dark bands and the abdomen with a row of black spots on
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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each side. The winged form is similar in size. However, the body often seems
to have a powdery coating. The insects feed in groups of 5 to over 2000. The
leaves fed with aphids usually turned blackish. Molds are normally present.
h. Jassid. The adult is the destructive stage. They damage by chewing the leaves
of corn. The adults damage at daytime. They are noticed damaging during the
vegetative until the maturity stage of the plant.
The color of the adult is light tan about 1/8-inch long (Fig. 11). Its most
distinguishing feature is the presence of two dark spot located between the
eyes.
i. Long horned grasshopper and katydid. The nymphs and the adults are
destructive. They are prevalent during and after the reproductive stages. The
insect feeds by chewing the leaves. They are active at daytime.
Long horned grasshopper measures 22mm, short antennae filiform and
threadlike (Fig. 12).
The katydid measures 18mm, wing span is 24mm. The abdomen consists
of 7 segments (Fig. 13).
j. Snout beetle, cockchafer, leaf beetle, western corn rootworm, and northern
corn rootworm. These pests of corn are attacking the leaves of the plants. The
adult is the destructive stage. These pest feed on the leaf by chewing. They are
active at day time.
Snout beetle is black, gray, or brown and measures 10 to 16 mm long.
They pierce young seedlings near the ground with their "beak," causing
stunting, tip dieback, and often death of corn seedlings. Plants which survive
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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display yellow streaks, suckering, and rows of holes transverse across the
blades (Fig. 14).
Cockchafer is robust, oblong, and hard-shelled. The beetle’s measures 19
to 25 mm long and reddish brown to black in color (Fig. 15).
The color of the leaf beetle is yellow with black spot it measures ¼-inch
long. The wing covers of male is entirely black except for narrow yellow
margins and yellow tips (Fig. 16).
The color of the western corn rootworm body is yellow with black spot
about ¼-inch long. They feed on the plants above ground, especially the
pollen and silks. During heavy infestation, grazing damage to the silks can
impair fertilization resulting in fewer kernels on the cob (Fig. 17).
The color of the body of northern corn rootworm is yellowish brown and
measures ¼-inch long (Fig. 18). Larva is about 1/2-inch long. Creamy white
in color except for the head capsule and a plate on the upper surface of the last
body segment.
k. Snail and slugs. These organisms belong to the class Gastropoda. The adult is
the destructive stage. They are damaging the vegetative until the maturity
stage. They were noticed damaging the leaves early in the morning and late in
the afternoon until the middle of the night.
The color of body of snail is brown. It measures 6.7 mm, 0.26 inches (Fig.
19). The slugs are best describes as snail without shell soft body. Generally
brownish or grayish with eye stalks. They vary in size from ¼ inch to two
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inches or longer. Slugs leave a silvery slime trail that they secrete as they
move (Fig 20).
Insects attacking the ear
a. Corn earworm. The larva is the destructive stage. The larva as it emerge from
the egg feeds on the leaves, tassel, whorl, and shift to the ears being the
preferred sites for damaging during the flowering stage. This worm feeds on
the tip kernels of the ear. The larva is active at day and night time. Losses of
the high eating quality of sweet corn are results of the damage by the corn
earworm.
The adult corn earworm moth has a wingspan of 25.5 to 38.5 mm. The
forewings of the male are usually a light yellowish-olive. Each forewing has a
dark spot near the center. The hind wings are white with a broad, dark brown,
outer marginal band and, usually, a narrow, brown, intermarginal band.
b. Corn borer. The larva as it bore the stem, the ear of sweet corn 75 is similarly
damaged. It is active damaging during the day and night time. They feed and
chew the inner portion of the ear.
c. Aphids. The nymphs and adults attack the ear of sweet corn. They damage by
sucking the ear portion that causes the discoloration.
Insects attacking the tassel
a. Corn borer. The larva attacks the tassel. They feed on tassel during the day
and night time.
b. Corn earworm. The larva attacks the tassel of the corn. The feed by chewing
the tassel during the day and night time.
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c. Aphids. The nymphs and adults are the destructive stages. They feed by
sucking on the tassel of corn. The feeding causes mottling and discoloration of
the parts damaged. They are active at day time.
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Classification of the pest associated with sweet corn sugar 75
The classification of the insects, snail and slug that are associated in sweet corn
variety sugar 75 are shown in Table 2. The details of the classification of the insects are
briefly discussed.
The order Lepidoptera. There were four (4) families of Lepidoptera feeding on
sweet corn sugar 75. These are the Pyralidae (Ostrinia furnicalis Gueene), Noctuidae
(Peridroma saucia Huner, Chrysodeixis chalcites Esper, Spodoptera fragiperda Smith,
Spodoptera litura Fabricius and Helicoverpa zea Boddie), Lymantriidae (Euproctis sp.
and Dasychira sp.) and Arctiidae (Spilosoma sp.) (Fig. 1-9)
The order Homoptera. There are two (2) families of Homoptera feeding on sweet
corn sugar 75. These are the Aphididae (Phopalosiphum maidis Fitch) and Cicadellidae
(Dalbulus maidis DeLong.) (Fig. 10 and 11).
The order Orthoptera. One (1) family of Orhtoptera feeding on sweet corn sugar
75. This is Tettigoniidae (Atractomorpha viridissima Bolivar and Pterophylla
camellifolia Thunberg). (Fig. 12 and 13).
The order Coleoptera. There were three (3) families of Coleoptera feeding on
sweet corn sugar 75. These are the Curculionidae (Gonepterus sp.), Scarabaeidae
(Melolontha melolontha Linnaeus) and Chrysomelidae (Labidomera clivicollis Kirby,
Diabrotica virgifera Wilcox, Diabrotica barberi Wilcox). (Fig. 14-18)
The phylum Mullosca. There are two species of phylum Mollusca feeding on
sweet corn sugar 75. These are the Helix aspersa Muller and Varginulus plebeia Fischer
(Fig. 19 and 20).
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Table 2. Classification of the Pest Associated with Sweet Corn Sugar 75
ORDER/FAMILY
SCIENTIFIC NAME
COMMON NAME
Order Lepidoptera
Pyralidae
Ostrinia furnicalis Gueene
Corn borer
Noctuidae
Peridroma saucia Hubner
Variegated cutworm
Noctuidae
Chrysodeixis chalcites Esper Semi-looper
Noctuidae
Spodoptera frugiperda Smith Armyworm
Noctuidae
Spodoptera litura Fabricius
Cluster caterpillar
Noctuidae
Helicoverpa zea Boddie
Corn earworm
Lymantriidae
Euproctis sp.
Tussock moth
Lymantriidae
Dasychira sp.
Tussock moth
Arctiidae
Spilosoma sp.
Wooly bear caterpillar
Order Homoptera
Aphididae
Rhopalosiphum maidis Fitch Aphids
Cicadellidae
Dalbulus maidis DeLong
Jassid
Order Orthoptera
Tettigoniidae
Attractomorpha
Long horned grasshopper
viridissima Bolivar
Tettigoniidae
Pterophylla camellifolia
Katydids
Thunberg
Order Coleoptera
Curculionidae
Gonepterus sp.
Snout beetle
Scarabaeidae
Melolontha melolontha
Cockchafer
Linnaeus
Chrysomelidae
Labidomera clivicollis Kirby Leaf beetle
Chrysomelidae
Diabrotica virgifera Wilcox Western corn rootworm
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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Table 2. Continued . . .
ORDER/FAMILY
SCIENTIFIC NAME
COMMON NAME
Chrysomelidae
Diabrotica barberi Wilcox
Northern corn rootworm
Phylum Mollusca
Class
Gastropoda
Helix aspersa Muller
Snail
Gastropoda
Vaginulus plebeia Fischer
Slug
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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Figure 1. Corn Borer
Figure 2. Variegated Cutworm
Order: Lepidoptera
Order: Lepidoptera
Family: Pyralidae
Family: Noctuidae
Genus: Ostrinia
Genus: Peridroma
Species: furnicalis
Species: saucia
Figure 3. Cluster Caterpillar
Figure 4. Semi-looper
Order: Lepidoptera
Order: Lepidoptera
Family: Noctuidae
Family: Noctuidae
Genus: Spodoptera
Genus: Chrysodeixis
Species: litura
Species: chalcites
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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Figure 5. Army worm
Figure 6. Corn earworm
Order: Lepidoptera
Order: Lepidoptera
Family: Noctuidae
Family: Noctuidae
Genus: Spodoptera
Genus: Helicoverpa
Species: frugiperda
Species: zea
Figure 7. Tussock moth
Figure 8. Tussock moth
Order: Lepidoptera Order: Lepidoptera
Family: Lymantriidae
Family: Lymantriidae
Genus: Euproctis
Genus: Dasychira
Species: sp.
Species: sp.
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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Figure 9. Woolly bear caterpillar
Figure 10. Corn aphids
Order: Lepidoptera Order: Homoptera
Family: Arctiidae
Family: Aphididae
Genus: Spilosoma
Genus: Rhopalosiphum
Species: sp.
Species: maidis
Figure 11. Jassid
Figure 12. Long horned grasshopper
Order: Homoptera Order: Orthoptera
Family: Cicadellidae
Family: Tettigoniidae
Genus: Dabulus
Genus: Atractomorpha
Species: Maidis
Species: viridissima
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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Figure 13. Katydid Figure 14. Snout beetle
Order: Orthoptera Order: Coleoptera
Family: Tettigoniidae Family: Curculionidae
Genus: Pterophylla Genus: Gonepterus
Species: camellifolia Species: sp.
Figure 15. Cockchafer
Figure 16. Leaf beetle
Order: Coleoptera
Order: Coleoptera
Family: Scarabaeidae
Family: Chrysomelidae
Genus: Melolontha
Gernus: Labidomera
Species: melolontha
Species: clivicollis
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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45Figure 17. Western corn rootworm
Figure 18. Northern corn rootworm
Order: Coleoptera
Order: Coleoptera
Family: Chrysomelidae
Family: Chrysomelidae
Genus: Diabrotica
Genus: Diabrotica
Species: virgifera
Species: barberi
Figure 19. Snail
Figure 20. Slugs
Phyllum: Mollusca
Phyllum: Mollusca
Class: Gastropoda
Class: Gastropoda
Genus: Helix
Gernus: Vaginulus
Species: aspersa
Species: plebeia
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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Degree of Injury
The result of the study showed that the most destructive pest was corn borer. The
degree of injury of the insect by the injury rating scale index was 9 which means that the
sweet corn plant was very severely damaged (Fig. 21) or with the actual damaged of 76
to 100%. Corn borer was followed by the variegated cutworm, armyworm, cluster
caterpillar and corn earworm with an injury rating index of 7. This level of injury rating
imply that the corn plants were severely damaged (Fig. 22, 24 25, and 26). The actual
damaged was 51 to 75%. The injury index for semi-looper, tussock moth (Euproctis sp.
and Dasychira sp.), wooly bear caterpillar and aphids is 5 implying that the plants were
moderately damaged (Fig. 23, 27, 28, 29, and 30) or with the actual damaged of 26 to
50%. The insect jassid, long horned grasshopper, katydid, snout beetle, cockchafer, leaf
beetle, western corn rootworm, northern corn rootworm, snail and slug were rated 3 or
slightly damaged (Fig. 31, 32, 33, 34, 35, 36, 37, 38, 39 and 40). With the injury rating of
3 it implies that the actual damaged on the plants is 1 to 25% damaged.
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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Table 3. Degree of injury of the insects, snails and slug associated on sweet corn 75
ORDER/
RATING
QUALITATIVE
DESCRIPTION
COMMON NAME
INDEX
INDEX
Lepidoptera
Corn borer
9
Very severely
76 to 100%damage on plant
damage
Variegated cutworm
7
Severely damage
51 to 75% damage on plant
Semi-looper
5
Moderately damage
26 to 50% damage on plant
Armyworm
7
Severely damage
51 to 75% damage on plant
Cluster caterpillar
7
Severely damage
51 to 75% damage on plant
Corn earworm
7
Severely damage
51 to 75% damage on plant
Tussock moth
5
Moderately damage
26 to 50% damage on plant
(Euproctis sp.)
Tussock moth
5
Moderately damage
26 to 50% damage on plant
(Dasychira sp.)
Woolly bear
5
Moderately damage
26 to 50% damage on plant
caterpillar
Homoptera
Aphids
5
Moderately damage
26 to 50% damage on plant
Jassid
3
Slightly damage
1 to 25% damage on plant
Orthoptera
Katydid
3
Slightly damage
1 to 25% damage on plant
Long horned
3
Slightly damage
1 to 25% damage on plant
grasshopper
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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Table 3. Continued . . .
ORDER/
RATING
QUALITATIVE
DESCRIPTION
COMMON NAME
INDEX
INDEX
Coleoptera
Snout beetle
3
Slightly damage
1 to 25% damage on plant
Cockchafer
3
Slightly damage
1 to 25% damage on plant
Leaf beetle
3
Slightly damage
1 to 25% damage on plant
Western corn
3
Slightly damage
1 to 25% damage on plant
rootworm
Northern corn
3
Slightly damage
1 to 25% damage on plant
rootworm
Gastropoda
Snail
3
Slightly damage
1 to 25% damage on plant
Slug
3
Slightly damage
1 to 25% damage on plant
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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Figure 21.Ostrinia furnicalis Gueene
Figure 22. Peridroma saucia Hubner
damage on the young stage of
damage on the vegetative stage of
sweet corn 75
sweet corn 75
Figure 23. Spodoptera litura Fabricius
Figure 24. Chrysodeixis chalcites Esper
damage on the young stage of
damage on the leaves of sweet corn
sweet corn 75
75
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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Figure 25. Spodoptera frugiperda Smith
Figure 26. Helicoverpa zea Boddie
damage on vegetative stage of
damage on the ear of sweet corn
sweet corn 75
75
Figure 27. Euproctis sp. damage
Figure 28. Dasychira sp. damage
on the vegetative stage of
on the flowering stage of sweet
sweet corn 75
corn 75
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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Figure 28. Spilosoma sp. damage on
Figure 30. Rhopalosiphum maidis Fitch
the leaves of sweet
damage on the ear of sweet corn 75
corn 75
Figure 31. Dalbulus maidis DeLong
Figure 32. Altractomorporpha viridissima
damage on the leaves of sweet
Bolivar damage on the leaves of
corn 75 sweet corn 75
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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Figure 33. Pterophylla camellifolia Figure 34. Gonepterus sp. damage on
Thunberg damage on the leaves
the hair of sweet corn 75
of sweet corn 75
Figure 35. Melolontha melolontha
Figure 36. Labidomera clivicollis Kirby
Linnaeus damage on the leaves of
damage on the leaves of sweet
sweet corn 75
corn 75
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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Figure 37. Diabrotica virgifera Wilcox
Figure 38. Diabrotica barberi Wilcox
damage on the leaves of sweet
damage on the leaves of sweet
corn 75
corn 75
Figure 39. Helix aspersa Muller damage
Figure 40. Vaginulus plebeia Fischer
on the leaves of sweet corn 75
damage on the leaves of sweet corn
75
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
34
Major and Minor Pest Associated with Sweet Corn Sugar 75
The classification of the insect either it is a major or minor pest was based on the
degree of damage. The insect is classified major pest if the level of damaged on sweet
corn is 50% and above and minor pest if the level of damage is 50% and below. The
result of evaluation is as follows:
Major pest. The major pest of sweet corn variety sugar 75 encountered were the
corn borer, variegated cutworm, army worm, cluster caterpillar, and corn earworm. These
insect pest feed on almost all part of the sweet corn sugar 75. The insects enumerated
above were classified in the order Lepidoptera.
Minor pests. The minor pests of sweet corn variety sugar 75 encountered were
aphids, jassid under, long horned grasshopper, katydid, snout beetle, cockchafer, leaf
beetle, western corn rootworm, northern corn rootworm, snail and slug.
Aphids and jassid were classified in the order Homoptera while the long horned
grasshopper and katydid were classified in the order Orthoptera. Snout beetle,
cockchafer, leaf beetle, western corn borer and northern corn rootworm were classified in
the order Coleoptera. The snail and slugs were classified in the class Gastropoda.
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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35
Table 4. Identified major and minor pests associated with sweet corn sugar 75
ORDER/SCIENTIFIC
COMMON NAME
MAJOR PEST
MINOR PEST
NAME
Order Lepidoptera
Ostrinia furnicalis
Corn borer
X
Gueene
Peridroma saucia
Variegated cutworm
X
Hubner
Chrysodeeixis
Semi-looper
X
chalcites Esper
Spodoptera
Armyworm
X
frugiperda Smith
Spodoptera litura
Cluster caterpillar
X
Fabricius
Helicoverpa zea
earworm
X
Boddie
Euproctis sp.
Tussock moth
X
Dasychira sp.
Tussock moth
X
Spilosoma sp.
Woolly bear caterpillar
X
Order Homoptera
Rhopalosiphum
Aphids
X
maidis Fitch
Dalbulus maidis
Jassid
X
DeLong
Order Orthoptera
Altratomorpha
Long horned grasshopper
X
viridissima
Bolivar
Pterophylla
Katydid
X
camellifolia
Thunberg
Order Coleoptera
Gonepterus sp.
Snout beetle
X
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
36
Table 4. Continued . . .
ORDER/SCIENTIFIC
COMMON NAME
MAJOR PEST
MINOR PEST
NAME
Melolontha
Cockchafer
X
melolontha
Linnaeus
Labidomera
Leaf beetle
X
clivicollis Kirby
Diabrotica
Western corn rootworm
X
virgifera Wilcox
Diabrotica barberi Northern corn rootworm
X
Wilcox
Class Gastropoda
Hilex aspersa
Snail
X
Muller
Varginulus plebeia
Slug
X
Fischer
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
37
SUMMARY, CONCLUSION AND RECOMMENDATION
Summary
The study was conducted at Benguet State University Balili Experimental Area,
La Trinidad Benguet from December to February 2008. The study was conducted to
know the insects and other related pests feeding on sweet corn variety sugar 75, record
the degree of injury caused by the insect pests on sweet corn variety sugar 75 and classify
the insets according to economic importance.
In the roots of sweet corn, there were no insects noted damaging based on the
results of this research. On the other hand, literature indicates that the insects damaging
on roots are white grubs, root webworm, cutworm and wireworm. The insects recorded
damaging on the stem of corn were corn borer, variegated cutworm, cluster caterpillar
and aphids. The recorded most destructive was corn borer. In the corn leaves, the insects
recorded damaging were corn borer, variegated cutworm, cluster caterpillar, semi-looper,
armyworm, corn earworm, tussock moth with genus of Euproctis sp. and Dasychira sp.,
aphids, jassid, long horned grasshopper, katydid, snout beetle, cockchafer, leaf beetle,
western corn rootworm, northern corn rootworm, snail and slugs. Among the insects
recorded, the most destructive were variegated cutworm, cluster caterpillar armyworm
and aphids. On the corn ear, the insects observed damaging were corn earworm, corn
borer, and aphids. The most destructive was corn earworm. In the tassel, the insects
damaging were corn borer, corn earworm and aphids with aphids and corn borer as the
two most destructive.
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
38
The corn borer, variegated cutworm, semi-looper, armyworm, cluster caterpillar,
corn earworm, tussock moth (Euproctis sp. and Dasychira sp.) and woolly bear
caterpillar) are feeding on the leaves, stem, and almost all part of the sweet corn sugar 75
at day and night. The aphids were feeding on leaves, stalk, flower and ear of the corn
during daytime. The jassid feed on the leaves of the corn at daytime. Long horned
grasshopper and katydid are feeding on the leaves of corn at daytime. The snout beetle,
cockchafer, leaf beetle, western corn rootworm and northern corn rootworm are feeding
on the leaves of the corn plants at daytime. The snail and slugs are feeding on the leaves
of sweet corn sugar 75 both at the day and night.
The most destructive pest of sweet corn sugar 75 was corn borer. This insect
causes damage in corn to as high as 76 to 100%. Corn borer was followed by variegated
cutworm, armyworm, cluster caterpillar, corn earworm and aphids with the degree of
damage of 26 to 50%. The jassid, snout beetle, cockchafer, leaf beetle, western corn
rootworm, northern corn rootworm, long horned grasshopper, katydid, snail and slugs
cause damage in corn of 1 to 25%.
Conclusion
Sweet corn sugar 75 is like other ordinary corn, is attractive for the infestation by
many kinds of pest insects and other related pest. These include corn borer, variegated
cutworm, armyworm, cluster caterpillar, and corn earworm as the major pest while the
minor pests are tussock moth (Euproctis sp. and Dasychira spp.), woolly bear caterpillar,
aphid’s, jassid, long horned grasshopper katydid, snout beetle, cockchafer, leaf beetle,
western corn rootworm, northern corn rootworm, snail and slugs.
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
39
Recommendation
Should there is a wide cultivation of sweet corn especially if it is intended for
commercial scale production, the insect pest as cited above must be given especial
attention for control.
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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LITERATURE CITED
JUCENHEIMER, R. W. 1976. Corn Improvement, Seed Production and Uses. New
York. John Wiley and Sons. Pp. 15-20.
MARTIN, J. H., W. H. LEONARD and D. L. STAMP. 1976. Principles of Field Crops
Production (3rd ed). London:Collier Macmillan Publishers. Pp. 325-339.
McCOLLUM, J. P. and G. WARE. 1980. Producing Vegetable Crops (3rd ed). The
Interstate Printers and Publishers, Inc. New York. p. 307.
MENDOILA, N. B. 1958. Annual Food Crops. Malabon, Rizal, Phillipnes. Araneta U
Press. Pp. 125-129.
MOSEMAN, A. H. 2006. “Corn”. Microsoft Encarta 2007 [CD]. Redmond, WA:
Microsoft Corporation.
OPINA, O.S., D.M. DIMAANO, E.M. GUTIERREZ, P.V. MALIGALIG, N.M.
SALCEDO and R.G. DALMACIO. 1983. Lepidoptereous Pest of Corn. Plant
Pest ClinicBulletin College of Agriculture University of the Philippines at Los
Banos College of Laguna.
THOMPSON, H. C. and W. C. KELLY. 1959. Vegetable Crops (5th ed). Tata McGraw
Hill Publishing Company I. T. D. New Delhi. Pp. 556-570.
WILSON, H. K. 1955. Grain Crops. New York. McGraw-Hill Book Company, Inc. p.
283.
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
BINAY-AN, PETER C. APRIL 2008. The Insect Pests of Sweet Corn, Sugar 75 (Zea
maize Saccharata) at La Trinidad, Benguet. Benguet State University, La Trinidad, Benguet.
Adviser: Eulogio V. Cardona Jr., PhD.
ABSTRACT
The study aims to know the insects and other related pests of sweet corn variety sugar 75,
record the degree of injury caused by the insect pests and classify the insets according to
economic importance.
In the roots of sweet corn, there were no insects noted damaging based on the results of
this research. On the other hand, literature indicates that the insects damaging on roots are white
grubs, root webworm, cutworm and wireworm. The insects recorded damaging on the stem of
corn were corn borer, variegated cutworm, cluster caterpillar and aphids. The recorded most
destructive was corn borer. In the corn leaves, the insects recorded damaging were corn borer,
variegated cutworm, cluster caterpillar, semi-looper, armyworm, corn earworm, tussock moth
with genus of Euproctis sp. and Dasychira sp., aphids, jassid, long horned grasshopper, Katydid,
snout beetle, cockchafer, leaf beetle, western corn rootworm, northern corn rootworm, snail and
slugs. Among the insects recorded, the most destructive were variegated cutworm, cluster
caterpillar, armyworm and aphids. On the corn ear, the insects observed damaging were corn
earworm, corn borer, and aphids. The most destructive was corn earworm. In the tassel, the
insects damaging were corn borer, corn earworm and aphids. Aphids and corn borer were the
two most destructive.
The most destructive pest of sweet corn sugar 75 was corn borer. This insect causes
damage in corn to as high as 76 to 100%. Corn borer was followed by variegated cutworm,
armyworm, cluster caterpillar, corn earworm and aphids with the degree of damage of 26 to
50%. The jassid, snout beetle, cockchafer, leaf beetle, western corn rootworm, northern corn
rootworm, long horned grasshopper, katydid, snail and slugs cause damage in corn from 1 to
25%.
TABLE OF CONTENTS
Page
Bibliography………………………………………………..…………….. i
Abstract…………………………………………………………………....
i
Table of Contents ………………………………………………………… iii
INTRODUCTION…………………………………………..…….……….
1
REVIEW OF LITERATURE….…………………………………………. 3
METHODOLOGY…………….…………………………………………. 6
RESULTS AND DISCUSSION
Insects and Related Pest Attacking
Sweet Corn 75 …………………………………………………….. 8
Classification of the Pest Associated with
Sweet Corn Sugar 75……………………………………………... 18
Degree of Injury…………………………………………………... 26
Major and Minor Pest Associated with
Sweet Corn Sugar 75...…………………………………………….. 34
SUMMARY, CONCLUSION AND RECOMMENDATION
Summary…………………………………………………………… 37
Conclusion………………………………………………………..... 38
Recommendation………………………………………………….. 39
LITERATURE CITED ………………………………………………..….. 40
INTRODUCTION
Corn, (Zea maize Linnaeus) is a world wide field crop adapted to semi-temperate
and tropical climates. It is an annual crop and belongs to the family graminnae. It is rich
in nutrient elements and serves many importance to human and industrial uses like in the
formulation of feeds for poultry and livestock’s. In the Philippines, corn is planted whole
year round in the provinces of Pangasinan, Isabela, Cagayan, Ilocos Region, Cebu, and
Central Mindanao. In Cebu, corn is the staple food crop of the Cebuano’s.
One variety of corn that attracts the attention of most consumers is the
development of the hybrid green corn. This variety has high demand in the market as
green corn. It is sold in the super market, along the sari-sari store and in public market.
Because of the persistent marketing strategies of the companies, the farmers in Benguet
have learned the planting of sweet corn. Normally, these are noted by strip cropping at
the end of vegetable plots and as for crop rotation. By observation, one of the limiting
factors for the production of green corn is the infestation of insect pests.
Literature indicates that the most destructive insects in corn are corn earworm,
European corn borer, southern corn rootworm, cutworm, white grub, and wireworm. The
underground insect pests normally inhabit the soil while they are injuring the plant. They
usually damage the roots or other subterranean parts of the plants. But some insects may
feed or injure parts of the plants above the soil. The more important soil insects include
cutworm, root aphid, rootworm, white grub, and wireworm. The insect pests on the stalk,
leaf and ear of corn are armyworm, chinch bug, earworm, European corn borer, flea
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
2
beetle, grass hopper, Japanese beetle, leaf aphid, and south western corn borer according
to Thompson and Kelly, (1959).
Identification of the various insect pests and other arthropods attacking corn
would be a great guide for future management to boost the production and quality of
corn. This means that appropriate control measure could only be provided for the sweet
corn sugar 75 should the insect pests be correctly identified.
The study was conducted to know the insects and other related pests feeding on
sweet corn variety sugar 75, record the degree of injury caused by these insect pest on
sweet corn variety sugar 75 and to classify the insets according to economic importance.
The study was conducted at Benguet State University Balili Experimental Area,
La Trinidad, Benguet from December 2007 to February 2008.
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
3
REVIEW OF LITERATURE
Importance of Corn
Corn which is classified as corncobs is an important source of furfural, a liquid
used in manufacturing nylon fibers and phenol-formaldehyde plastics, refining wood
resin, making lubricating oils from petroleum, and purifying butadiene in the production
of synthetic rubber. Ground corncobs are used as a soft-grit abrasive. Large whole cobs
from a special type of corn are used for pipes for smoking tobacco oil, as cooking and
salad oil and as margarine. It is also used in the manufacturing of paints, scups, and
linoleum. The search for alternate source of energy has brought attention to corn as a fuel
source. Corn is processed to produce alcohol for use with gasoline as gasohol. The dry
stalk is potentially important for fuel biomass (Moseman, 2006).
Jugenheimer (1976) cited that corn has many uses; it is used primarily as food for
human in most areas of the world, for livestock feeds where about eighty five (85)
percent of the crop is fed to livestock, industrial uses which may be divided into four
categories; mixed feed manufactures, dry process millers; wet processes, and distilling
and fermentation industries.
Cultural Practices of Corn
Jugenheimer (1976) reported that the corn perform well on well-drained, fertile
soil and in areas with moderately high summer temperatures, warm nights, and adequate
but not excessive rainfall. Similarly, corn prefer-well-aerated deep, warm loams
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
4
containing abundance of organic matters, nitrogen’s, phosphorous, and potassium. The
amount, distribution, and efficiency of rain fall also are importance factors.
Corn plant has an erect and solid stem. It varies widely in height. Some dwarf
varieties are more than 60 cm or more. The average height of corn is 2.4 m. The leaves
which grow alternately are long and narrow. The main stalk terminates in a staminate
(male) inflorescence. The tassel is made up of many small flowers termed spikelets, and
each spikelet bears tree small anthers, which produce the pollen grains, or male gametes.
The pistellate (female) inflorescence of the ear is a unique structure with up to 1,000
seeds borne on a hard core called the cob. The ear is enclosed in modified leaves called
husk. The individual silk fibers that produce from the tip of the ear are the elongated
styles, each attached to an individual ovary. Pollen from the tassel is carried by the wind
and falls onto the silks, where it germinates and grows down through the silk until it
reaches the ovary. Each fertilized ovary grows and developed into a kernel (Moseman,
2006).
Common Insect Pest Associated with Corn
McCollum and Ware (1980) cited that the principal insects of corn are the corn
earworm, the southern corn stalk borer, and the European corn borer. Mendiola (1958)
stated that the most common insect pest is corn borer, corn earworm and the corn weevil.
Opina et al., (1983) stated that among the serious insect pests of corn, lepidopterous pests
are considered the major constraint in corn production. They attack almost all stages of
plant development. The corn borer (Ostrinia furnacalis Gueene) and corn earworm
(Helicoverpa armigera Hubner) may severely attack young plants and they usually
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
5
persist up to maturity. Vegetative stage of the crop is usually vulnerable to army worm
(Mythimna separata Walker), cutworm (Spodoptera litura Fabr.) and semi-looper
(Chrysodeixes chalcites Esper).
Other Insects of Corn
Other insects attacking corn are corn leaf aphid (Aphis maidis), maize billbug
(Sphenophorus maidis), corn flea beetle (Chaetocnema pulicaria), desert corn flea beetle
(C. ectypa), larger corn-stalk borer (Diatraea zeacolella), rough-headed corn-stalk beetle
(Euetheda rugiceps), white grub (Phyllophaga species), corn-root webworm or budworm
(Crambus caliginosellus), maize billbug (Calendra maidis), seed-corn maggot (Hylemyia
platora), wireworm, webworm, and the Japanese beetle (Martin et al., 1976).
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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METHODOLOGY
An area of about 200 square meters was prepared at the Benguet State University
Balili Experimental Area, La Trinidad, Benguet. The area was cleaned from weeds and
cultivated using grab hoe, shovel, bolo, and other materials. After cleaning and
cultivating the plots, chicken manure was applied. Planting was done on plots with a
dimension of 1x10 meters. All agronomic practices as required by the plants were
provided.
The observation on the insects and arthropods associated damaging the crop was
done upon the germination of the plants until harvesting. Observation was fixed at
weekly interval until harvest. Collected insects and other related pests were brought in the
laboratory and were identified. The taxonomic hierarchy: order, family, genus, species,
common name was the basis for identification. Entomology related books, internet, and
other references were used as reference materials. The insects infesting the roots were
evaluated when the ears were harvested. Fifty corn plants were uprooted in the roots were
scrutinized for the presence of insects.
Monitoring the degree of injury by the pest insects was determined through
percentage by visual estimation of the whole plant. For example, the sample plants were
rated by visual observation using the following index:
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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ORDER/COMMON RATING QUALITATIVE
DESCRIPTION
NAME
INDEX
INDEX
1
No damage
No injury
3
Slightly damage
1 to 25 % damage on plant
5
Moderately damage
26 to 50% damage on plant
7
Severely damage
51 to 75% damage on plant
9
Very severely damage
76 to 100% damage on plant
Insect’s degree of damage of above 51% was considered major pest and minor
pest for those insects with a level of injury of below 50%.
Data Gathered:
1.
Various insects damaging on sugar 75. The insects and other related pests
collected were identified by using entomology related books, internet and other
references.
2.
Degree of injury. The degree of injury in percent (%) by the insects on
sweet corn 75 were assessed.
3.
Major and minor pest. The insect pests that has the degree of injury of
51% and above is considered major pests and minor pests for those insects with a degree
of injury of 50% and below.
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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RESULTS AND DISCUSSION
Insects and Related Pest Associated Attacking Sweet Corn 75
The details of the various insect pests and non- insect pests associated damaging
on sweet corn sugar 75 are presented in Table 1. The insects are presented according to
the parts of corn they damage. Discussion on the insect’s nature of damage, the stage of
the plant they damage and morphological description of the insects are likewise
presented.
Insects’ attacking the roots. Literature indicates the existence of white grubs, root
webworm, cutworm and wireworm attacking the roots of corn. In these study however,
these insect pests were not encountered.
Insects attacking the stem
a. Corn borer. The larva is the destructive stage while the adults are not
injurious. The larva upon emergence from the egg, feeds on the leaves by
chewing. After few more days or when the larva has reached the 3rd instar,
they transfer to the stem and feed by chewing. They are actively feeding at
night and at daytime. The larva damages the stem by chewing and as a result
the stem is bored. The part of the stem near the developing corn ear is
preferred for damaging. As a result of boring, the stem becomes weak and
blown down when there are strong winds. The larva is present in the corn
damaging during the late vegetative stage until maturity.
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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Table 1. Destructive stages and time were they active attacking sweet corn 75
PARTS OF PLANT/
TIME
DESTRUCTIVE
PARTS OF THE PLANT THEY
THEY
STAGE
ATTACK
COMMON NAME
ATTACK
Day Night
Larva Nymph Adult Roots Stem leaves Ear Tassel
Roots*
White grubs
X
X
X
X
Corn-root webworm
X
X
X
X
Corn cutworm
X
X
X
X
X
Wireworm
X
X
X
X
Stem
Corn borer
X
X
X
X
X
X
X
Variegated cutworm
X
X
X
X
X
Cluster caterpillar
X
X
X
X
Aphids
X
X
X
X
X
X
X
Leaves
Corn borer
X
X
X
X
X
X
X
Variegated cutworm
X
X
X
X
X
Semi-looper
X
X
X
Armyworm
X
X
X
X
Cluster caterpillar
X
X
X
X
Tussock moth
X
X
X
X
(Euproctis sp. and
Dasychira sp.)
∗ Insects of the roots of sweet corn were not observed in this study. The insects presented
above were taken from literature.
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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Table 1. Continued . . .
PARTS OF PLANT/
TIME
DESTRUCTIVE
PARTS OF THE PLANT THEY
THEY
STAGE
ATTACK
COMMON NAME
ATTACK
Day Night
Larva Nymph Adult Roots Stem leaves Ear Tassel
Woolly bear caterpillar
X
X
X
X
Aphids
X
X
X
X
X
X
X
Jassids
X
X
X
Katydid
X
X
X
Long horned grasshopper X
X
X
Snout beetle
X
X
X
X
Cockchafer
X
X
X
X
X
Leaf beetle
X
X
X
X
Western corn rootworm
X
X
X
X
X
X
Northern corn rootworm
X
X
X
X
X
X
Snail
X
X
X
X
Slug
X
X
X
X
X
Ear
Corn borer
X
X
X
X
X
X
X
Corn earworm
X
X
X
X
X
X
X
Aphids
X
X
X
X
X
X
X
Tassel
Corn borer
X
X
X
X
X
X
X
Corn earworm
X
X
X
X
X
X
X
Aphids
X
X
X
X
X
X
X
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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The destructive larva is slender, bluish-green, brown-striped caterpillar up
to 19 mm long (Fig. 1). The adults are small, tan, night fliers about ½ inches
in length that hold their wings in a delta shape when at rest.
b. Variegated cutworm and cluster caterpillar. The larva or the worm stage
damages the stem. The adults are not destructive. The larva cut off the stem of
young corn. Normally, they are destructive to the young and growing corn.
They are active at night time and hide under debris on the soil surface at day
time.
The body of variegated cutworm measures 1 to 1.75 inches in length and
commonly curl into a C-shape when disturbed (Fig. 2). The color is greenish
brown with several longitudinal stripes. The body of cluster caterpillar
measures 1.5 to 2.0 inches long (Fig. 3). The adults or moths are
approximately 1 inch long with a wing span of 1.25 to 2 inches and vary
widely in coloration. The eggs are somewhat flattened on top, white to dull or
off-white in color.
c. Aphids. The nymphs and adults are destructive. Aphids damage by sucking
the juice of the corn stem. The insect was noticed damaging the stem only
during the early vegetative stage.
Insects attacking the leaves
a. Corn borer. Corn borer was noted damaging on the leaves only when the
insects are still small. The larva damage by chewing the leaves. This is soon
after emergence from the eggs. But since the larva is small as they just
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
12
emerged from egg, the damage they normally create on the leaves is very
small to negligible.
b. Variegated cutworm and cluster caterpillar. This worm climbs the stem and
damages the leaves. The larva chews and cut off the leaves of young plants.
They are active at night time. During the day, they hide under debris on the
soil surface. The insect is noticeable in corn only during the early emergence
stage of the plant.
c. Semi-looper. The larva is the destructive stage. The adult is free living while
the larva feeds on underside of the leaves, making windows between the
veins. The leaf area affected is silvery to pale gray in color.
The full grown insect is 25-30 mm long. The body is green with green
stripes along the body (Fig. 4).
d. Armyworm. The larva is the destructive stage while the adult is free living.
The worm feeds initially on the leaf margins. The larva feeds in colonies and
skeletonizes leaves of near vegetative until maturity. The larva feeds singly on
leaves during daytime. They are prevalent during the early emergence until
early vegetative stage.
The young armyworm is pale green. The mature larva is basically
yellowish- or brownish-green with a tan or greenish- brown head mottled with
dark brown. The smooth, practically hairless body is marked with three
longitudinal dark stripes, one along each side and one down the back. A full
grown armyworm is 30 to 35 mm long (Fig. 5). The adult armyworm moth is
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
13
grayish-brown forewings, each with a white spot near the center, and grayish-
white hind wings. The wingspan averages 38.5 mm.
e. Corn earworm. The early stage larva damages the leaves. The larva damage
by chewing the leaves. The insect is prevalent during the late vegetative until
the maturity stage. As noticed, damage on the leaves is small to negligible.
The presence of the insect on the leaves is temporary as the corn ear is the
preferred part for damaging.
The body color of corn earworm is pale green or pinkish to brown. It
measures 1.5 to 1.6 inches long (Fig. 6).
f. Tussock moth (Euproctis sp. and Dasychira sp.) and woolly bear caterpillar.
The larva is the destructive stage while the adult are free living. The larva
feeds by chewing the side parts of the leaves. Feeding is done at daytime.
The young larva measures 1/8 to ¼ inch (4-7 mm) long. They have fine
body hairs which later develop into tufts. Mature larvae measures ¼ inch (3.1
cm) long. They are colorful (Fig. 7 and 8). The body color of woolly bear
caterpillar is brownish to black. It measures 2 1/8 inch (55 mm) long (Fig. 9)
g. Aphids. The nymphs and adults are destructive. Aphid’s damage by sucking
the juice of the corn leaves. The insect were noticed damaging during the
early vegetative until maturity stage. However, they are prevalent during the
flowering stage.
The body of aphids measures 2.0 mm long (Fig. 10). The color is pale
bluish-green with black antennae, legs and cornicles. The head is marked with
two longitudinal dark bands and the abdomen with a row of black spots on
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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each side. The winged form is similar in size. However, the body often seems
to have a powdery coating. The insects feed in groups of 5 to over 2000. The
leaves fed with aphids usually turned blackish. Molds are normally present.
h. Jassid. The adult is the destructive stage. They damage by chewing the leaves
of corn. The adults damage at daytime. They are noticed damaging during the
vegetative until the maturity stage of the plant.
The color of the adult is light tan about 1/8-inch long (Fig. 11). Its most
distinguishing feature is the presence of two dark spot located between the
eyes.
i. Long horned grasshopper and katydid. The nymphs and the adults are
destructive. They are prevalent during and after the reproductive stages. The
insect feeds by chewing the leaves. They are active at daytime.
Long horned grasshopper measures 22mm, short antennae filiform and
threadlike (Fig. 12).
The katydid measures 18mm, wing span is 24mm. The abdomen consists
of 7 segments (Fig. 13).
j. Snout beetle, cockchafer, leaf beetle, western corn rootworm, and northern
corn rootworm. These pests of corn are attacking the leaves of the plants. The
adult is the destructive stage. These pest feed on the leaf by chewing. They are
active at day time.
Snout beetle is black, gray, or brown and measures 10 to 16 mm long.
They pierce young seedlings near the ground with their "beak," causing
stunting, tip dieback, and often death of corn seedlings. Plants which survive
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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display yellow streaks, suckering, and rows of holes transverse across the
blades (Fig. 14).
Cockchafer is robust, oblong, and hard-shelled. The beetle’s measures 19
to 25 mm long and reddish brown to black in color (Fig. 15).
The color of the leaf beetle is yellow with black spot it measures ¼-inch
long. The wing covers of male is entirely black except for narrow yellow
margins and yellow tips (Fig. 16).
The color of the western corn rootworm body is yellow with black spot
about ¼-inch long. They feed on the plants above ground, especially the
pollen and silks. During heavy infestation, grazing damage to the silks can
impair fertilization resulting in fewer kernels on the cob (Fig. 17).
The color of the body of northern corn rootworm is yellowish brown and
measures ¼-inch long (Fig. 18). Larva is about 1/2-inch long. Creamy white
in color except for the head capsule and a plate on the upper surface of the last
body segment.
k. Snail and slugs. These organisms belong to the class Gastropoda. The adult is
the destructive stage. They are damaging the vegetative until the maturity
stage. They were noticed damaging the leaves early in the morning and late in
the afternoon until the middle of the night.
The color of body of snail is brown. It measures 6.7 mm, 0.26 inches (Fig.
19). The slugs are best describes as snail without shell soft body. Generally
brownish or grayish with eye stalks. They vary in size from ¼ inch to two
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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inches or longer. Slugs leave a silvery slime trail that they secrete as they
move (Fig 20).
Insects attacking the ear
a. Corn earworm. The larva is the destructive stage. The larva as it emerge from
the egg feeds on the leaves, tassel, whorl, and shift to the ears being the
preferred sites for damaging during the flowering stage. This worm feeds on
the tip kernels of the ear. The larva is active at day and night time. Losses of
the high eating quality of sweet corn are results of the damage by the corn
earworm.
The adult corn earworm moth has a wingspan of 25.5 to 38.5 mm. The
forewings of the male are usually a light yellowish-olive. Each forewing has a
dark spot near the center. The hind wings are white with a broad, dark brown,
outer marginal band and, usually, a narrow, brown, intermarginal band.
b. Corn borer. The larva as it bore the stem, the ear of sweet corn 75 is similarly
damaged. It is active damaging during the day and night time. They feed and
chew the inner portion of the ear.
c. Aphids. The nymphs and adults attack the ear of sweet corn. They damage by
sucking the ear portion that causes the discoloration.
Insects attacking the tassel
a. Corn borer. The larva attacks the tassel. They feed on tassel during the day
and night time.
b. Corn earworm. The larva attacks the tassel of the corn. The feed by chewing
the tassel during the day and night time.
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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c. Aphids. The nymphs and adults are the destructive stages. They feed by
sucking on the tassel of corn. The feeding causes mottling and discoloration of
the parts damaged. They are active at day time.
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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Classification of the pest associated with sweet corn sugar 75
The classification of the insects, snail and slug that are associated in sweet corn
variety sugar 75 are shown in Table 2. The details of the classification of the insects are
briefly discussed.
The order Lepidoptera. There were four (4) families of Lepidoptera feeding on
sweet corn sugar 75. These are the Pyralidae (Ostrinia furnicalis Gueene), Noctuidae
(Peridroma saucia Huner, Chrysodeixis chalcites Esper, Spodoptera fragiperda Smith,
Spodoptera litura Fabricius and Helicoverpa zea Boddie), Lymantriidae (Euproctis sp.
and Dasychira sp.) and Arctiidae (Spilosoma sp.) (Fig. 1-9)
The order Homoptera. There are two (2) families of Homoptera feeding on sweet
corn sugar 75. These are the Aphididae (Phopalosiphum maidis Fitch) and Cicadellidae
(Dalbulus maidis DeLong.) (Fig. 10 and 11).
The order Orthoptera. One (1) family of Orhtoptera feeding on sweet corn sugar
75. This is Tettigoniidae (Atractomorpha viridissima Bolivar and Pterophylla
camellifolia Thunberg). (Fig. 12 and 13).
The order Coleoptera. There were three (3) families of Coleoptera feeding on
sweet corn sugar 75. These are the Curculionidae (Gonepterus sp.), Scarabaeidae
(Melolontha melolontha Linnaeus) and Chrysomelidae (Labidomera clivicollis Kirby,
Diabrotica virgifera Wilcox, Diabrotica barberi Wilcox). (Fig. 14-18)
The phylum Mullosca. There are two species of phylum Mollusca feeding on
sweet corn sugar 75. These are the Helix aspersa Muller and Varginulus plebeia Fischer
(Fig. 19 and 20).
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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Table 2. Classification of the Pest Associated with Sweet Corn Sugar 75
ORDER/FAMILY
SCIENTIFIC NAME
COMMON NAME
Order Lepidoptera
Pyralidae
Ostrinia furnicalis Gueene
Corn borer
Noctuidae
Peridroma saucia Hubner
Variegated cutworm
Noctuidae
Chrysodeixis chalcites Esper Semi-looper
Noctuidae
Spodoptera frugiperda Smith Armyworm
Noctuidae
Spodoptera litura Fabricius
Cluster caterpillar
Noctuidae
Helicoverpa zea Boddie
Corn earworm
Lymantriidae
Euproctis sp.
Tussock moth
Lymantriidae
Dasychira sp.
Tussock moth
Arctiidae
Spilosoma sp.
Wooly bear caterpillar
Order Homoptera
Aphididae
Rhopalosiphum maidis Fitch Aphids
Cicadellidae
Dalbulus maidis DeLong
Jassid
Order Orthoptera
Tettigoniidae
Attractomorpha
Long horned grasshopper
viridissima Bolivar
Tettigoniidae
Pterophylla camellifolia
Katydids
Thunberg
Order Coleoptera
Curculionidae
Gonepterus sp.
Snout beetle
Scarabaeidae
Melolontha melolontha
Cockchafer
Linnaeus
Chrysomelidae
Labidomera clivicollis Kirby Leaf beetle
Chrysomelidae
Diabrotica virgifera Wilcox Western corn rootworm
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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Table 2. Continued . . .
ORDER/FAMILY
SCIENTIFIC NAME
COMMON NAME
Chrysomelidae
Diabrotica barberi Wilcox
Northern corn rootworm
Phylum Mollusca
Class
Gastropoda
Helix aspersa Muller
Snail
Gastropoda
Vaginulus plebeia Fischer
Slug
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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Figure 1. Corn Borer
Figure 2. Variegated Cutworm
Order: Lepidoptera
Order: Lepidoptera
Family: Pyralidae
Family: Noctuidae
Genus: Ostrinia
Genus: Peridroma
Species: furnicalis
Species: saucia
Figure 3. Cluster Caterpillar
Figure 4. Semi-looper
Order: Lepidoptera
Order: Lepidoptera
Family: Noctuidae
Family: Noctuidae
Genus: Spodoptera
Genus: Chrysodeixis
Species: litura
Species: chalcites
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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Figure 5. Army worm
Figure 6. Corn earworm
Order: Lepidoptera
Order: Lepidoptera
Family: Noctuidae
Family: Noctuidae
Genus: Spodoptera
Genus: Helicoverpa
Species: frugiperda
Species: zea
Figure 7. Tussock moth
Figure 8. Tussock moth
Order: Lepidoptera Order: Lepidoptera
Family: Lymantriidae
Family: Lymantriidae
Genus: Euproctis
Genus: Dasychira
Species: sp.
Species: sp.
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Figure 9. Woolly bear caterpillar
Figure 10. Corn aphids
Order: Lepidoptera Order: Homoptera
Family: Arctiidae
Family: Aphididae
Genus: Spilosoma
Genus: Rhopalosiphum
Species: sp.
Species: maidis
Figure 11. Jassid
Figure 12. Long horned grasshopper
Order: Homoptera Order: Orthoptera
Family: Cicadellidae
Family: Tettigoniidae
Genus: Dabulus
Genus: Atractomorpha
Species: Maidis
Species: viridissima
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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Figure 13. Katydid Figure 14. Snout beetle
Order: Orthoptera Order: Coleoptera
Family: Tettigoniidae Family: Curculionidae
Genus: Pterophylla Genus: Gonepterus
Species: camellifolia Species: sp.
Figure 15. Cockchafer
Figure 16. Leaf beetle
Order: Coleoptera
Order: Coleoptera
Family: Scarabaeidae
Family: Chrysomelidae
Genus: Melolontha
Gernus: Labidomera
Species: melolontha
Species: clivicollis
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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45Figure 17. Western corn rootworm
Figure 18. Northern corn rootworm
Order: Coleoptera
Order: Coleoptera
Family: Chrysomelidae
Family: Chrysomelidae
Genus: Diabrotica
Genus: Diabrotica
Species: virgifera
Species: barberi
Figure 19. Snail
Figure 20. Slugs
Phyllum: Mollusca
Phyllum: Mollusca
Class: Gastropoda
Class: Gastropoda
Genus: Helix
Gernus: Vaginulus
Species: aspersa
Species: plebeia
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
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Degree of Injury
The result of the study showed that the most destructive pest was corn borer. The
degree of injury of the insect by the injury rating scale index was 9 which means that the
sweet corn plant was very severely damaged (Fig. 21) or with the actual damaged of 76
to 100%. Corn borer was followed by the variegated cutworm, armyworm, cluster
caterpillar and corn earworm with an injury rating index of 7. This level of injury rating
imply that the corn plants were severely damaged (Fig. 22, 24 25, and 26). The actual
damaged was 51 to 75%. The injury index for semi-looper, tussock moth (Euproctis sp.
and Dasychira sp.), wooly bear caterpillar and aphids is 5 implying that the plants were
moderately damaged (Fig. 23, 27, 28, 29, and 30) or with the actual damaged of 26 to
50%. The insect jassid, long horned grasshopper, katydid, snout beetle, cockchafer, leaf
beetle, western corn rootworm, northern corn rootworm, snail and slug were rated 3 or
slightly damaged (Fig. 31, 32, 33, 34, 35, 36, 37, 38, 39 and 40). With the injury rating of
3 it implies that the actual damaged on the plants is 1 to 25% damaged.
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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Table 3. Degree of injury of the insects, snails and slug associated on sweet corn 75
ORDER/
RATING
QUALITATIVE
DESCRIPTION
COMMON NAME
INDEX
INDEX
Lepidoptera
Corn borer
9
Very severely
76 to 100%damage on plant
damage
Variegated cutworm
7
Severely damage
51 to 75% damage on plant
Semi-looper
5
Moderately damage
26 to 50% damage on plant
Armyworm
7
Severely damage
51 to 75% damage on plant
Cluster caterpillar
7
Severely damage
51 to 75% damage on plant
Corn earworm
7
Severely damage
51 to 75% damage on plant
Tussock moth
5
Moderately damage
26 to 50% damage on plant
(Euproctis sp.)
Tussock moth
5
Moderately damage
26 to 50% damage on plant
(Dasychira sp.)
Woolly bear
5
Moderately damage
26 to 50% damage on plant
caterpillar
Homoptera
Aphids
5
Moderately damage
26 to 50% damage on plant
Jassid
3
Slightly damage
1 to 25% damage on plant
Orthoptera
Katydid
3
Slightly damage
1 to 25% damage on plant
Long horned
3
Slightly damage
1 to 25% damage on plant
grasshopper
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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Table 3. Continued . . .
ORDER/
RATING
QUALITATIVE
DESCRIPTION
COMMON NAME
INDEX
INDEX
Coleoptera
Snout beetle
3
Slightly damage
1 to 25% damage on plant
Cockchafer
3
Slightly damage
1 to 25% damage on plant
Leaf beetle
3
Slightly damage
1 to 25% damage on plant
Western corn
3
Slightly damage
1 to 25% damage on plant
rootworm
Northern corn
3
Slightly damage
1 to 25% damage on plant
rootworm
Gastropoda
Snail
3
Slightly damage
1 to 25% damage on plant
Slug
3
Slightly damage
1 to 25% damage on plant
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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Figure 21.Ostrinia furnicalis Gueene
Figure 22. Peridroma saucia Hubner
damage on the young stage of
damage on the vegetative stage of
sweet corn 75
sweet corn 75
Figure 23. Spodoptera litura Fabricius
Figure 24. Chrysodeixis chalcites Esper
damage on the young stage of
damage on the leaves of sweet corn
sweet corn 75
75
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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Figure 25. Spodoptera frugiperda Smith
Figure 26. Helicoverpa zea Boddie
damage on vegetative stage of
damage on the ear of sweet corn
sweet corn 75
75
Figure 27. Euproctis sp. damage
Figure 28. Dasychira sp. damage
on the vegetative stage of
on the flowering stage of sweet
sweet corn 75
corn 75
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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Figure 28. Spilosoma sp. damage on
Figure 30. Rhopalosiphum maidis Fitch
the leaves of sweet
damage on the ear of sweet corn 75
corn 75
Figure 31. Dalbulus maidis DeLong
Figure 32. Altractomorporpha viridissima
damage on the leaves of sweet
Bolivar damage on the leaves of
corn 75 sweet corn 75
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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Figure 33. Pterophylla camellifolia Figure 34. Gonepterus sp. damage on
Thunberg damage on the leaves
the hair of sweet corn 75
of sweet corn 75
Figure 35. Melolontha melolontha
Figure 36. Labidomera clivicollis Kirby
Linnaeus damage on the leaves of
damage on the leaves of sweet
sweet corn 75
corn 75
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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Figure 37. Diabrotica virgifera Wilcox
Figure 38. Diabrotica barberi Wilcox
damage on the leaves of sweet
damage on the leaves of sweet
corn 75
corn 75
Figure 39. Helix aspersa Muller damage
Figure 40. Vaginulus plebeia Fischer
on the leaves of sweet corn 75
damage on the leaves of sweet corn
75
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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34
Major and Minor Pest Associated with Sweet Corn Sugar 75
The classification of the insect either it is a major or minor pest was based on the
degree of damage. The insect is classified major pest if the level of damaged on sweet
corn is 50% and above and minor pest if the level of damage is 50% and below. The
result of evaluation is as follows:
Major pest. The major pest of sweet corn variety sugar 75 encountered were the
corn borer, variegated cutworm, army worm, cluster caterpillar, and corn earworm. These
insect pest feed on almost all part of the sweet corn sugar 75. The insects enumerated
above were classified in the order Lepidoptera.
Minor pests. The minor pests of sweet corn variety sugar 75 encountered were
aphids, jassid under, long horned grasshopper, katydid, snout beetle, cockchafer, leaf
beetle, western corn rootworm, northern corn rootworm, snail and slug.
Aphids and jassid were classified in the order Homoptera while the long horned
grasshopper and katydid were classified in the order Orthoptera. Snout beetle,
cockchafer, leaf beetle, western corn borer and northern corn rootworm were classified in
the order Coleoptera. The snail and slugs were classified in the class Gastropoda.
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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Table 4. Identified major and minor pests associated with sweet corn sugar 75
ORDER/SCIENTIFIC
COMMON NAME
MAJOR PEST
MINOR PEST
NAME
Order Lepidoptera
Ostrinia furnicalis
Corn borer
X
Gueene
Peridroma saucia
Variegated cutworm
X
Hubner
Chrysodeeixis
Semi-looper
X
chalcites Esper
Spodoptera
Armyworm
X
frugiperda Smith
Spodoptera litura
Cluster caterpillar
X
Fabricius
Helicoverpa zea
earworm
X
Boddie
Euproctis sp.
Tussock moth
X
Dasychira sp.
Tussock moth
X
Spilosoma sp.
Woolly bear caterpillar
X
Order Homoptera
Rhopalosiphum
Aphids
X
maidis Fitch
Dalbulus maidis
Jassid
X
DeLong
Order Orthoptera
Altratomorpha
Long horned grasshopper
X
viridissima
Bolivar
Pterophylla
Katydid
X
camellifolia
Thunberg
Order Coleoptera
Gonepterus sp.
Snout beetle
X
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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Table 4. Continued . . .
ORDER/SCIENTIFIC
COMMON NAME
MAJOR PEST
MINOR PEST
NAME
Melolontha
Cockchafer
X
melolontha
Linnaeus
Labidomera
Leaf beetle
X
clivicollis Kirby
Diabrotica
Western corn rootworm
X
virgifera Wilcox
Diabrotica barberi Northern corn rootworm
X
Wilcox
Class Gastropoda
Hilex aspersa
Snail
X
Muller
Varginulus plebeia
Slug
X
Fischer
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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SUMMARY, CONCLUSION AND RECOMMENDATION
Summary
The study was conducted at Benguet State University Balili Experimental Area,
La Trinidad Benguet from December to February 2008. The study was conducted to
know the insects and other related pests feeding on sweet corn variety sugar 75, record
the degree of injury caused by the insect pests on sweet corn variety sugar 75 and classify
the insets according to economic importance.
In the roots of sweet corn, there were no insects noted damaging based on the
results of this research. On the other hand, literature indicates that the insects damaging
on roots are white grubs, root webworm, cutworm and wireworm. The insects recorded
damaging on the stem of corn were corn borer, variegated cutworm, cluster caterpillar
and aphids. The recorded most destructive was corn borer. In the corn leaves, the insects
recorded damaging were corn borer, variegated cutworm, cluster caterpillar, semi-looper,
armyworm, corn earworm, tussock moth with genus of Euproctis sp. and Dasychira sp.,
aphids, jassid, long horned grasshopper, katydid, snout beetle, cockchafer, leaf beetle,
western corn rootworm, northern corn rootworm, snail and slugs. Among the insects
recorded, the most destructive were variegated cutworm, cluster caterpillar armyworm
and aphids. On the corn ear, the insects observed damaging were corn earworm, corn
borer, and aphids. The most destructive was corn earworm. In the tassel, the insects
damaging were corn borer, corn earworm and aphids with aphids and corn borer as the
two most destructive.
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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The corn borer, variegated cutworm, semi-looper, armyworm, cluster caterpillar,
corn earworm, tussock moth (Euproctis sp. and Dasychira sp.) and woolly bear
caterpillar) are feeding on the leaves, stem, and almost all part of the sweet corn sugar 75
at day and night. The aphids were feeding on leaves, stalk, flower and ear of the corn
during daytime. The jassid feed on the leaves of the corn at daytime. Long horned
grasshopper and katydid are feeding on the leaves of corn at daytime. The snout beetle,
cockchafer, leaf beetle, western corn rootworm and northern corn rootworm are feeding
on the leaves of the corn plants at daytime. The snail and slugs are feeding on the leaves
of sweet corn sugar 75 both at the day and night.
The most destructive pest of sweet corn sugar 75 was corn borer. This insect
causes damage in corn to as high as 76 to 100%. Corn borer was followed by variegated
cutworm, armyworm, cluster caterpillar, corn earworm and aphids with the degree of
damage of 26 to 50%. The jassid, snout beetle, cockchafer, leaf beetle, western corn
rootworm, northern corn rootworm, long horned grasshopper, katydid, snail and slugs
cause damage in corn of 1 to 25%.
Conclusion
Sweet corn sugar 75 is like other ordinary corn, is attractive for the infestation by
many kinds of pest insects and other related pest. These include corn borer, variegated
cutworm, armyworm, cluster caterpillar, and corn earworm as the major pest while the
minor pests are tussock moth (Euproctis sp. and Dasychira spp.), woolly bear caterpillar,
aphid’s, jassid, long horned grasshopper katydid, snout beetle, cockchafer, leaf beetle,
western corn rootworm, northern corn rootworm, snail and slugs.
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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Recommendation
Should there is a wide cultivation of sweet corn especially if it is intended for
commercial scale production, the insect pest as cited above must be given especial
attention for control.
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
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LITERATURE CITED
JUCENHEIMER, R. W. 1976. Corn Improvement, Seed Production and Uses. New
York. John Wiley and Sons. Pp. 15-20.
MARTIN, J. H., W. H. LEONARD and D. L. STAMP. 1976. Principles of Field Crops
Production (3rd ed). London:Collier Macmillan Publishers. Pp. 325-339.
McCOLLUM, J. P. and G. WARE. 1980. Producing Vegetable Crops (3rd ed). The
Interstate Printers and Publishers, Inc. New York. p. 307.
MENDOILA, N. B. 1958. Annual Food Crops. Malabon, Rizal, Phillipnes. Araneta U
Press. Pp. 125-129.
MOSEMAN, A. H. 2006. “Corn”. Microsoft Encarta 2007 [CD]. Redmond, WA:
Microsoft Corporation.
OPINA, O.S., D.M. DIMAANO, E.M. GUTIERREZ, P.V. MALIGALIG, N.M.
SALCEDO and R.G. DALMACIO. 1983. Lepidoptereous Pest of Corn. Plant
Pest ClinicBulletin College of Agriculture University of the Philippines at Los
Banos College of Laguna.
THOMPSON, H. C. and W. C. KELLY. 1959. Vegetable Crops (5th ed). Tata McGraw
Hill Publishing Company I. T. D. New Delhi. Pp. 556-570.
WILSON, H. K. 1955. Grain Crops. New York. McGraw-Hill Book Company, Inc. p.
283.
The Insect Pests of Sweet Corn, Sugar 75 (Zea maize Saccharata) at La Trinidad, Benguet.
BINAY-AN, PETER C. APRIL 2008
Document Outline
- BIBLIOGRAPHY
- TABLE OF CONTENTS
- INTRODUCTION