BIBLIOGRAPHY LUIS, LEILA P. MAY 2007. Effect...
BIBLIOGRAPHY
LUIS, LEILA P. MAY 2007. Effect of Rust-Infected Mulberry Leaves Fed to
PTRI SW-3 Hybrid Silkworm (Bombyx mori L.) on the Quality of Cocoon Yield in La
Trinidad, Benguet. Benguet State University, La Trinidad, Benguet.
Adviser: Valentino L. Macanes, MSc
ABSTRACT
The study was conducted to determine the effect of mulberry leaves infected by
rust fed to hybrid silkworms (PTRI SW-3) on the quality and quantity of cocoons
produced and to evaluate the susceptibility of silkworms (PTRI SW-3) fed with rust-
infected mulberry leaves (Batac var.) to silkworm diseases.
Results of this study revealed no significant effect rust-infected mulberry leaves
fed to silkworms on larval duration, whole cocoon weight, cocoon shell percentage and
mortality rate. However, moderate and severe rust infection to mulberry leaves affected
the raw silk properties of cocoons. Slight rust-infected mulberry leaves fed to hybrid
silkworms had the highest mean on the number of good cocoons produced with a low
number of defective cocoons. This was followed by silkworms fed with moderately rust-
infected mulberry leaves. Meanwhile, the silkworms fed with mulberry leaves that were
severely infected with mulberry rust produced the lowest number of good cocoons with a
high number of defective cocoons. In addition, undernourished silkworm larvae were also
observed in this treatment and these silkworms were not able to spin cocoons.
No silkworm disease occurrence was observed during the period of the study.
TABLE OF CONTENTS
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Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
REVIEW OF LITERATURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
MATERIALS AND METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5
RESULTS AND DISCUSSION
Larval Duration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10
Number of Good Cocoons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11
Number of Defective Cocoons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11
Number of Good Cocoons Contained
in a One (1) Liter Cylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12
Weight of Good Cocoons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
Weight of Whole Cocoon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
Weight of Cocoon Shell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
Cocoon Shell Percentage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
Mortality Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
Cocoon Filament Length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16
Thickness of the Cocoon Filament . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17
SUMMARY, CONCLUSION AND RECOMMENDATION . . . . . . . . . . . . . .
18
LITERATURE CITED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20
APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21
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1
INTRODUCTION
Rust is one of the most important diseases affecting mulberry plants. This maybe
caused by either Aecidium mori or Cerotelium fici. Both pathogens belong to Order
Urticales of Class Basidiomycetes. The A. mori affects the leaves, petioles, tender buds
and even fruits. On the other hand, C. fici affects the leaves only. Rust reduces the
nutritional value needed by the silkworms (Bugnay, 1995).
The quality and suitability of the mulberry foliage have direct effect on both the
vitality of the silkworm and the yield, quality of cocoons and quality of silk filaments,
therefore, must be taken in choosing the best quality of leaves to be able to meet the
requirements of the different growing stage of silkworm larvae particularly in the young
ages. At the same time quantity of mulberry leaves must be provided to maintain regular
growth (Pang-chuan et al., 1986).
The choice of mulberry leaves as the sole food suitable to the age and growth of
the silkworm larvae is one of the most important considerations in sericulture. Leaves for
young ages (1st –3rd instars) must be soft, succulent, rich in protein, carbohydrates and
minerals. While for the grown up stage (4th –5th instars) wherein the silk glands are being
developed leaves must be rich in protein and fiber (Balingan, 1994).
Krishnawasmi (1973) found that starvation and underfeeding of worms lead to
poor growth and weakening which leads to susceptibility of silkworms to diseases. If the
larval stage is prolonged, this indicates that rearing is not suitable. Therefore, the rearer
must be accurate in feeding the desired number of worms so that the leaves given will be
fully utilized. He further discovered that the adequacy of feeds minimizes prolonged
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
2
larval duration and undernourished silkworms whose effects results to poor quality and
quantity of cocoons produced.
On the other hand, Celis (1997) stated that mulberry silkworms are fed three (3)
times a day. Feeding them in proper time and giving the right quality of leaves contribute
greatly to success of cocoon quality.
Silkworms are affected by various types of diseases. These include infection by
pathogenic microorganisms like viral diseases, bacterial diseases, fungal diseases and
protozoan infection. Likewise, the physiology of silkworms is easily affected by
environmental factors such as weather conditions, technique of rearing, quality of
mulberry feed and silkworm variety (Veda et al., 1997).
Thus this study was conducted to serve as a guide for students, researchers, and
farmers who are presently engaged in sericulture and for those who intend to go into
sericulture production. This study will help in choosing the quality of mulberry leaves to
be fed to silkworms to avoid profit loss. In addition, the study aimed to determine the
effect of mulberry leaves infected by rust fed to hybrid silkworms (PTRI SW-3) on the
quality and quantity of cocoons produced and to evaluate the susceptibility of silkworms
(PTRI SW-3) fed with rust-infected mulberry leaves (Batac var.) to silkworm diseases.
This study was conducted at the Benguet State University Sericulture Project
located at Ampasit, Puguis, La Trinidad, Benguet and the Philippine Textile Research
Institute (PTRI) Laboratory, Km. 6, La Trinidad, Benguet from January to May 2007.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
3
REVIEW OF LITERATURE
Mulberry tree (Morus spp.) belongs to the family Moraceae of genus Morus. It is
the sole food of silkworms (Bombyx mori L.) (Bugnay, 1995). However, the plants are
affected by several types of diseases. There are about twenty (20) diseases which usually
attack mulberry plants that needs careful preventive measures and some of these includes
fungus, bacteria, mycoplasma, and viruses. Most of the diseases are infectious and affects
either the entire plant or selectively the roots, stems and leaves (Veda et. al., 1997).
Diocares (1978) as cited by Cawa-it (2006) stated that rust-infected plants show
increase water loss because they transpire more water through ruptured dermis. In
addition, the fungus competes with the plants by absorbing more nutrients and water.
Likewise, the photosynthesis of the plants is considerably reduced. Furthermore, UNDP-
ESCAP (1999) stated that mulberry rust causes 90-100% damage to mulberry plants.
Besides, rust-infected mulberry leaves affects the nutrition of the mulberry silkworms.
Inferior quality cocoons maybe produced from silkworms fed with low quality of
mulberry leaves.
Silkworms are stenophagous insects that feeds on mulberry leaves. Their life
cycle is completed by passing through four (4) stages; egg, larva, pupa and adult (moth).
At the pupal stage, the body is defenseless against external enemies hence the silkworm
larvae spins a protective shell around its body called cocoons. These are made up of
silkfibers which is secreted from a pair of silkgland extruded through the silkworms
spinneret. In sericulture, the larvae are killed in the cocoon after several days of spinning.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
4
Killing is done either by steam or hot air. This procedure is done to soften the sericin for
easy filament winding (Veda et. al., 1997).
Diocares (1978) observed that young silkworm larvae require different diet in
comparison with that of the later stages. Young larvae needs comparatively soft,
succulent leaves with less starch and fiber. On the other hand, the mature larvae requires
high protein and carbohydrate content but les moisture. He also reported that proper
nutrient coupled with proper time of feeding and rearing techniques are necessary in
obtaining high quality and quantity of silk.
Celis (1997) stated that attention must be given to ensure that the quality of
harvested mulberry leaves is maintained. Mulberry leaves should be stored in cool place
and out of direct sunlight, polyethylene and wet cloth sheet maybe used to provide cool
temperature and high humidity. Leaves not well kept easily wilts, that which helps
reduces silkworms feeding appetite.
Delayed feeding of mulberry silkworm affects the physiological functioning of
their body. Hence, the growth rate of the worms is hindered. Starvation leads to poor and
weakening of the worms. The worms ultimately becomes susceptible to diseases since
prolonged larval duration of the different instars leads to poor growth of the latter stage
and poor development of silkglands (Krishnawasmi, 1973).
Meanwhile, Pang-chuan et al. (1986) stated that water content of leaves losses
more than 10% of its original weight. They further found that because of this the appetite
of the silkworms will significantly lessen. If it losses more than 30%, the consumption of
the mulberry leaves will decrease to less than half of the quantity of the food stuff and
under ordinary conditions, silkworms will refuse to eat.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
5
MATERIALS AND METHODS
The important materials used in the study were as follows: PTRI SW-3 hybrid
mulberry silkworm (Bombyx mori L.) and mulberry leaves (Batac variety). The mulberry
leaves were classified as follows: slightly rust-infected, moderately rust-infected, and
severely rust-infected. The other materials and equipment included: power sprayer,
rearing trays, rearing stands, weighing scale, heater, thermohygrometer, cocooning frame,
knife, chopping board, cleaning nets, paraffin paper, news papers, pruning shear,
mulberry baskets, wet cloth, and data sheets. The chemicals used were: formalin (3%),
powdered lime, disinfectant soap and rubbing alcohol (75%)
Nine hundred newly-hatched hybrid silkworm larvae of PTRI SW-3 were reared
in the rearing house and were fed with different quality of Batac mulberry leaves. The
study was conducted using the simple Completely Randomized Design (CRD) with three
(3) treatments each replicated three (3) times. The study used the percentage rate scale for
mulberry rust infection rating as recommended by Subba Rao et al. (1991) as cited by
Strange (1993). The treatments were the following:
Treatment Leaf
Quality
Disease Severity Rating
1 Slight
Rust
Infection
1-25%
2
Moderate Rust Infection
26-75%
3 Severe
Rust
Infection
76-100%
Rearing of silkworm was conducted following the rearing procedure
recommended by the Philippine Textile Research Institute (PTRI) as adapted by the
Benguet State University (BSU) Sericulture Project at Puguis, La Trinidad, Benguet.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
6
Rearing house disinfection. Before rearing started, the room and implements were
cleaned, washed and dried. The 3% formalin solution were prepared. The solution was
sprayed to the rearing room using the power sprayer, After spraying, the rearing room
was tightly closed for 24 hours to ensure effective disinfection. This was done ten (10)
days before brushing. Disinfection is effective at higher temperature thus, it was done at
11:00 am. The other implements these were soaked in 2% formalin solution and sun
dried.
Brushing. Newly-hatched silkworm larvae were separated from their shells by
placing finely chopped mulberry leaves over them. Afterwards, it was transferred in a
clean rearing tray by brushing the worms with the use of white, clean feather.
Feeding. Feeding was done three (3) times a day respectively; at 7:00 am, 1:00
pm and 6:00 pm. Young ages (1st to 3rd instar larvae) were fed with finely-chopped
mulberry leaves taken near the shoot. On the other hand, the grown-up stage (4th to 5th
instar larvae) were fed with the whole mature leaves.
Bed cleaning. Bed cleaning was done using nets placed on top of the rearing tray
with finely chopped mulberry leaves for the young ages. On the other hand, whole mature
leaves for the grown-up stage were placed on top of the rearing tray over the worms. The
net was lifted when all the larvae have crawled up, and is transferred to a separate tray.
This was done to prevent accumulation of uneaten mulberry leaves, fecal matters and
dead larvae that would eventually ferment and produce poisonous gas that affect the
silkworms.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
7
Bed spacing. The silkworms in the rearing bed were regularly spread to prevent
overcrowding that may cause irregular growth and even susceptibility to diseases. This
was done using a clean bird feather or chopstick.
Mounting. Matured silkworm larvae were picked from the rearing trays and were
mounted on the rotary mounting frame. Cocoon harvesting was done seven days after
mounting.
Cocoon harvesting. Harvesting of the cocoons was done seven days after
mounting. Harvested cocoons were deflossed and sorted, respectively, in each treatment
replications.
All the required temperature and room humidity for each instars strictly followed
during the silkworm rearing.
The data gathered were:
1. Larval duration. This was taken by counting the number of days from hatching
to mounting.
2. Cocoon yield quality. Harvested cocoons were deflossed, sorted and were
evaluated per treatment replicate using the following parameters:
a. Number of good cocoons. This was gathered by counting the number of good
cocoons produced per treatment replicate.
b. Number of defective cocoons. This was taken by counting the number of
defective cocoons which include the following: double, perforated, malformed, fluffy,
thin end stained dead cocoons.
c. Number of good cocoons contained per one (1) liter cylinder. This was
measured by counting the number of good cocoons contained in a one (1) liter cylinder.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
8
d. Cocoon weight (g). This was measured by weighing the good cocoons using
the weighing scale.
e. Whole cocoon weight (g). This was gathered by weighing five sample good
cocoons using the Mettler’s Balance. The samples were randomly picked from the
treatment replicates.
f. Cocoon shell weight (g). This was taken by cutting the five sample good
cocoons used in getting the whole cocoon weight. The pupae and exuviae were removed,
afterwhich, cocoon shell of the five sample cocoons were weighed. The average cocoon
shell weight was taken using the following formula:
Weight of sample cocoons
CSW =
5
g. Cocoon shell percentage (%). This was taken from the five sample good
cocoons using this formula:
Weight of cocoon shell x 100
CSP =
Weight of whole cocoon
3. Mortality rate (%). This was taken by counting the number of dead larvae from
each treatment replicate from hatching to the mounting of the silkworms. This was taken
using the following formula:
Number of diseased/dead larvae x 100
MR =
Number of worms per replicate
4.Rawsilk
properties. This was evaluated using the following parameters:
a. Length of cocoon filament (m). This was measured by reeling three sample
cocoons per treatment replicate in an epprovette.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
9
b. Thickness of the filament (Denier). This was gathered by weighing the silk
bave. Afterwhich, it was solved using the following formula:
Weight of silk bave x 9000m
Denier =
Length of rawsilk
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
10
RESULTS AND DISCUSSION
Larval Duration
Table 1 shows no significant differences on the number of the days that the
silkworm (PTRI SW-3) had completed their larval stage. All the three treatments showed
the same mean of 29 days.
.Table 1. Larval duration of the PTRI SW-3 fed with rust- infected mulberry leaves.
TREATMENT MEAN
(days)
1 – Slight rust infection
29
2 – Moderate rust infection
29
3 – Severe rust infection
29
Means with the same letter are not significantly different at 5% level using DMRT
Number of Good Cocoons
Table 2 shows the number of good cocoons produced from each treatment.
Statistical analysis revealed that there was a highly significant differences among the
treatments. The silkworms fed with mulberry leaves slightly infected by rust (T1) had the
highest mean which is 83.67 followed by silkworms fed with leaves moderately infected
with rust (T2) with a mean of 75.00. On the other hand, Treatment 3, (silkworms fed with
mulberry leaves severely infected by rust) gave the lowest mean of 66.67.
. This signifies that the quality of mulberry leaves fed to the silkworms greatly
affected the number of good cocoons produced. Results of the study confirms the
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
11
findings of UNDP-ESCAP (1999) that inferior quality of cocoons maybe produced from
silkworms fed with disease infected mulberry leaves.
Table 2. Number of good cocoons obtained from the different rust- infected mulberry
leaves
TREATMENT MEAN
1 – Slight rust infection
83.69a
2 – Moderate rust infection
75.00b
3 – Severe rust infection
66.67c
Means with the same letter are not significantly different at 5 % level using DMRT
Number of Defective Cocoons
The number of defective cocoons harvested from each treatment replicate is
presented in Table 3. Statistical analysis revealed that there was a highly significant
differences among the treatments. Treatment 3, (silkworms fed with mulberry leaves
having severe rust-infection) gave the highest mean of 83.33 defective cocoons followed
by the Treatment 2, (silkworms fed with mulberry leaves having moderate rust infection)
with a mean of 21.33 defective cocoons. Finally, Treatment 1 (silkworms fed with
mulberry leaves having slight rust infection) gave the lowest mean of 13.00 defective
cocoons.
This study affirms the discovery of Pang-chuan et al. (1986) that the quality and
suitability of mulberry foliage have direct effect on both the vitality of silkworm and the
quality of cocoons produced.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
12
Table 3. Number of defective cocoons obtained from the treatments fed with rust –
infected mulberry leaves
TREATMENT MEAN
1 – Slight rust infection
13.00c
2 – Moderate rust infection
21.33b
3 – Severe rust infection
28.33a
Means with the same letter are not significantly different at 5 % level using DMRT
Number of Good Cocoons Contained
in a One (1) Liter Cylinder
Table 4 shows the number of good cocoons contained in a one (1) liter cylinder.
Statistical analysis showed highly significant differences. Treatment 3 gave the highest
mean number of good cocoons contained in one liter cylinder with 94.67, followed by
Treatment 2 with 91.33. Finally, Treatment 1 gave the lowest mean of good cocoons in
one liter cylinder with 78.67.
This finding implies that the quality of mulberry leaves fed to silkworms affected
the cocoon size produced from each treatment. Slight rust infection of mulberry leaves
produce bigger cocoon size while severe rust infection of mulberry leaves produce
smaller size of cocoons
Table 4. Number of good cocoons contained in a 1 liter cylinder taken from mulberry
PTRI SW-3 fed with rust -infected mulberry leaves
TREATMENT MEAN
1 – Slight rust infection
78.67b
2 – Moderate rust infection
91.33a
3 – Severe rust infection
94.67 a
Means with the same letter are not significantly different at 5 % level using DMRT
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
13
Weight of Good Cocoons
The weight of good cocoons is presented in Table 5. Results showed that there
was highly significant differences among the treatments as found by statistical analysis.
Treatment 1 gave the highest mean weight of good cocoons with 140.180 grams, while
Treatment 2 had 113.573 grams. Finally, Treatment 3 gave the lowest mean of good
cocoons with 100.83grams.
Table 5. Weight of good cocoons per replicate harvested from PTRI SW-3 fed rust –
infected mulberry leaves
TREATMENT MEAN
(g)
1 – Slight rust infection
140.180 a
2 – Moderate rust infection
113.573b
3 – Severe rust infection
100.083b
Means with the same letter are not significantly different at 5 % level using DMRT
Weight of Whole Cocoon
Table 6 shows the whole cocoon weight produced by silkworms fed with different
quality of mulberry leaves. Statistical analysis showed no significant differences on the
PTRI SW-3 silkworms fed with the rust–infected mulberry leaves. However, the
silkworms fed with leaves having slight rust infection (T1) recorded the highest mean of
1.80 grams followed by the silkworms fed with leaves having moderate rust infection
(T2) with a mean of 1.79. Finally, the silkworms fed with leaves having severe rust
infection (T3) gave the lowest mean of 1.75 grams.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
14
Table 6. Whole cocoon weight produced by PTRI SW-3 fed with rust-infected mulberry
leaves
TREATMENT MEAN
(g)
1 – Slight rust infection
1.80
2 – Moderate rust infection
1.79
3 – Severe rust infection
1.75
Means with the same letter are not significantly different at 5 % level using DMRT
Weight of Cocoon Shell
The cocoon shell weight obtained from each treatment is shown in Table 7.
Statistical analysis found significant differences among the different treatments.
Treatment 1 had the highest mean cocoon shell weight of 0.38 grams while both
Treatments 2 and 3 gave the same mean of 0.35 grams cocoon shell weight.
This result proves that Treatment 1 (slightly rust-infected mulberry leaves fed to
silkworms) produced better cocoon quality than that of the moderate and severely rust-
infected leaves.
Table 7. Cocoon shell weight taken from PTRI SW-3 fed with rust-infected mulberry
leaves
TREATMENT MEAN
(g)
1 – Slight rust infection
0.38 a
2 – Moderate rust infection
0.35 b
3 – Severe rust infection
0.35 b
Means with the same letter are not significantly different at 5 % level using DMRT
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
15
Cocoon Shell Percentage
Table 8 shows the cocoon shell percentage taken from the different treatments.
Statistically, no significant differences among the treatments. However, Treatment 1 gave
the highest mean of 21.41% cocoon shell percentage, while Treatment 2 gave a mean of
19.68%. Finally, Treatment 3 gave the lowest mean of 19.67% cocoon shell percentage.
Table 8. Cocoon shell percentage taken from the PTRI SW-3 fed with rust-infected
mulberry leaves
TREATMENT MEAN
(%)
1 – Slight rust infection
21.41
2 – Moderate rust infection
19.68
3 – Severe rust infection
19.67
Means with the same letter are not significantly different at 5 % level using DMRT
Mortality Rate
Table 9 presents the mortality rate of the silkworms fed with the different rust
infection of mulberry leaves. Statistical analysis shows no significant differences among
the treatments. However, Treatment 3 gave the highest mean of 5.33% mortality rate and
Treatment 2 had a mean of 3.66 %. Treatment 1 gave the lowest mortality rate with a
mean of 3.33%.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
16
Table 9. Mortality rate obtained from the different percentage of PTRI SW-3 fed with
rust-infected mulberry leaves
TREATMENT MEAN
(%)
1 – Slight rust infection
3.33
2 – Moderate rust infection
3.66
3 – Severe rust infection
5.33
Means with the same letter are not significantly different at 5 % level using DMRT
Cocoon Filament Length
The filament length gathered from the different treatments is presented in Table
10. Significant difference among the treatments was observed as revealed by statistical
analysis. The highest mean filament length was obtained from Treatment 1 (silkworms
fed with mulberry leaves slightly-infected with rust) which gave 1170.67 meters. This
was followed by Treatment 2 (silkworms fed with mulberry leaves moderately-infected
with rust) with a mean of 1,024.00 meters. Finally, Treatment 3 (silkworms fed with
mulberry leaves severely-infected with rust) gave the lowest mean of 996.78 meters
cocoon filament length.
The quality of silk filament was greatly affected by quality of mulberry leaves
given to silkworms.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
17
Table 10. Cocoon filament length produced by PTRI SW-3 fed with rust infected
mulberry leaves
TREATMENT MEAN
(m)
1 – Slight rust infection
11.70.67 a
2 – Moderate rust infection
1024.00 ab
3 – Severe rust infection
996.78 b
Means with the same letter are not significantly different at 5 % level using DMRT
Thickness of the Cocoon Filament
The thickness of cocoon filament is shown in Table 11. Statistical analysis
showed that there were significant differences among the treatments. The silkworms fed
mulberry leaves slightly-infected with rust (T1) produced the thickest filament with 3.52
denier followed by Treatment 2 (moderate rust infection) with a mean of 3.48 denier.
Finally, the silkworms fed with mulberry leaves with severe rust infection (T3) gave the
lowest denier size of 3.44.
Table 11. Thickness of the cocoon filament harvested from the PTRI SW-3 fed with rust-
infected mulberry leaves
TREATMENT MEAN
(Denier)
1 – Slight rust infection
3.52 a
2 – Moderate rust infection
3.48 ab
3 – Severe rust infection
3.44 b
Means with the same letter are not significantly different at 5 % level using DMRT
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
18
SUMMARY, CONCLUSION AND RECOMMENDATION
Summary
The study was conducted to determine the effect of rust – infected mulberry
leaves fed to hybrid silkworms (PTRI SW-3) on the quality and quantity of cocoons
produced. Likewise, it was done to evaluate the susceptibility of silkworms (PTRI SW-3)
to silkworm diseases when fed with rust - infected mulberry leaves The parameters used
in evaluating the effect of rust-infected mulberry leaves were: larval duration, cocoon
yield quality particularly, number of good cocoons, number of defective cocoons, number
of good cocoons contained in one (1) liter cylinder, whole cocoon weight, cocoon shell
weight, cocoon shell percentage and larval mortality rate. Raw silk properties were also
taken, specifically, on the length of cocoon filament and the size of cocoon filament.
Hybrid silkworm PTRI SW-3 was used in the study. The silkworm was fed with
different quality of mulberry leaves classified as: slight rust infection (T1), moderate rust
infection (T2), and severe rust infection (T3).
Nine hundred (900) silkworm larvae were reared at Benguet State University
Sericulture Project located at Puguis, La Trinidad, Benguet from hatching to cocoon
harvesting. The standard silkworm rearing procedure was strictly followed. The harvested
cocoons were assessed at Philippine Textile Research Institute Laboratory located at Km.
6, Betag, La Trinidad, Benguet. The study was conducted from January to May 2007.
The study used Completely Randomized Design (CRD).
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
19
The results of the study found that there were highly significant differences
observed on the PTRI SW-3 hybrid silkworm on the number of good cocoons, number of
defective cocoons, number of good cocoons contained in one (1) liter cylinder and the
weight of good cocoons per replicate, when fed with rust-infected mulberry leaves. The
silkworms fed with mulberry leaves slightly infected with rust gave the best cocoon
quality and raw silk properties. This was followed by silkworms fed with mulberry leaves
moderately infected by rust. Finally, the PTRI SW-3 hybrid silkworms fed with mulberry
leaves severely infected with rust gave the lowest cocoon quality and raw silk properties.
However, no significant differences were taken on the following parameters: larval
duration, whole cocoon weight, cocoon shell percentage and mortality rate.
Conclusion
The result of the study showed that the hybrid mulberry silkworm (PTRI SW-3)
fed with slightly rust-infected mulberry leaves produce the best quality of good cocoons
compared with the other treatments.
Recommendation
The results of this study recommend that the percentage of rust infection to
mulberry leaves to be fed to hybrid silkworms should be taken into consideration in
silkworm rearing. Mulberry leaves with severe rust infection should not be utilized for
silkworm rearing. However, this experiment should also be tried in rearing pure breed
silkworms. Likewise this study should be done also in other locations and silkworm
rearing seasons.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
20
LITERATURE CITED
BALINGAN, S. 1994. Evaluation of the larval development and cocoon quality of four
F1 hybrid silkworms (Bombyx mori L.) in Benguet. BS Thesis. Benguet State
University, La Trinidad, Benguet. P. 5.
BUGNAY, L. B. 1995. Performance of silkworm (Bombyx mori L.) fed with mulberry
leaves sprayed with fungicides. BS Thesis. Benguet State University, La Trinidad,
Benguet. Pp. 1-4.
CAWA-IT, E. B. 2006. Field efficacy of fungicides for the control of mulberry red rust
(Aecidium mori B.) in La Trinidad. BS Thesis. Benguet State University, La
Trinidad, Benguet. Pp. 4-6.
CELIS, S. P. 1997. Influence of different methods of storing mulberry leaves on the
cocoon yield of JC 102 silkworm variety. BS Thesis. Benguet State University,
La Trinidad, Benguet. Pp. 3-5.
DIOCARES, C. 1978. Comparative effects of feeding frequency on a strain of silkworm
(Bombyx mori L.). BS Thesis. Benguet State University, La Trinidad, Benguet. P.
4.
KRISHNAWASMI, S. R. 1973. Silkworm feeding trials for evaluating the quality of
mulberry leaves as influenced by variety, spacing and nitrogen fertilization.
Biological abstract. Pp. 10, 79 and 89.
PANG-CHUAN, W. H. GUANG-XIAN, M. MABEN AND T. YUN-FANG. 1986.
Mulberry Cultivation. Food Agricultural Organization. Agricultural Services
Bulletin. Rome. Pp. 99-101.
STRANGE, R. N. 1993. Plant Disease Control. First Edition. Chapman and Hall.
Boundary Row, London, England. P. 94.
UNITED NATIONS DEVELOPMENT PROGRAM - ECONOMIC AND SOCIAL
COMMISSION FOR ASIA AND THE PACIFIC. 1999. Handbook on Mulberry
Pest and Diseases. UNDP-ESCAP. Bangkok, Thailand. Pp. 89-93.
VEDA, K., I. NAGAI, AND M. HORIKOMI. 1997. Silkworm Rearing. Science
Publishers Incorporation. U.S.A. Pp. 1 and 90.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
21
APPENDICES
Appendix Table 1. Larval duration (days)
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 29
29
29
87
29
T2 29
29
29
87
29
T3 29
29
29
87
29
TOTAL 87 87 87 261 87
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
22
Appendix Table 2. Number of good cocoons
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 85
82
84
251
83.667
T2 75
78
72
225
75.000
T3 68
67
65
200
66.667
TOTAL 228 227 221 676
75.111
ANALYSIS OF VARIANCE
SOURCE OF
DEGREES
SUM OF
MEAN
COMPUTED
TABULATED F
VARIATION
OF
SQUARES
SUM OF
F
F
FREEDOM
SQUARES
0.05 F
0.01
Treatment 2 433.5555
216.7777
47.59** 5.15 10.92
Error 6
27.3333
4.5555
Total
8
460.8888
**
highly
significant
CV
=
2.84%
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
23
Appendix Table 3. Number of defective cocoons
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 12
15
12
39
13
T2 20
19
25
64
21.33
T3 30
28
27
85
28.33
TOTAL 62 62 64 188
20.88
ANALYSIS OF VARIANCE
SOURCE OF
DEGREES
SUM OF
MEAN
COMPUTED
TABULATED F
VARIATION
OF
SQUARES
SUM OF
F
F
FREEDOM
SQUARES
0.05 F
0.01
Treatment 2 353.5555
176.7777
33.85** 5.15 10.92
Error 6
31.3333
5.2222
Total
8
384.8888
** highly significant
CV = 10.43%
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
24
Appendix Table 4. Number of good cocoons contained in a 1 liter cylinder
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 80
76
80
236
78.67
T2 92
90
92
272
90.67
T3 98
96
90
284
94.67
TOTAL 270 262 262 792
88.00
ANALYSIS OF VARIANCE
SOURCE OF
DEGREES
SUM OF
MEAN
COMPUTED
TABULATED F
VARIATION
OF
SQUARES
SUM OF
F
F
FREEDOM
SQUARES
0.05 F
0.01
Treatment 2 427.5555
213.7777
26.72** 5.15 10.92
Error 6
48.0000
8.0000
Total
8
475.5555
**
highly
significant
CV
=
3.20%
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
25
Appendix Table 5. Weight of good cocoons per replicate (g)
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 148.16
135.69
136.69
420.54
140.18
T2 116.28
122.38
102.06
340.72
113.57
T3 97.85
99.40
103.00
300.25
100.08
TOTAL 362.29
357.47
341.75
1,061.51
117.94
ANALYSIS OF VARIANCE
SOURCE OF
DEGREES
SUM OF
MEAN
COMPUTED
TABULATED F
VARIATION
OF
SQUARES
SUM OF
F
F
FREEDOM
SQUARES
0.05 F
0.01
Treatment 2 2497.6374 124.88187
22.88** 5.15 10.92
Error 6
327.4225
54.5704
Total
8
2825.0600
**
highly
significant
CV
=
6.26%
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
26
Appendix Table 6. Whole cocoon weight (g)
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 1.82
1.78
1.81
5.41
1.80
T2 1.78
1.78
1.83
5.39
1.80
T3 1.82
1.68
1.75
5.25
1.75
TOTAL 5.42 5.24 5.39
16.05
5.35
ANALYSIS OF VARIANCE
SOURCE OF
DEGREES
SUM OF
MEAN
COMPUTED
TABULATED F
VARIATION
OF
SQUARES
SUM OF
F
F
FREEDOM
SQUARES
0.05 F
0.01
Treatment 2 0.0050
0.0025 1.23ns 5.15 10.92
Error 6 0.0123
0.0020
Total
8
0.0174
ns
-
not
significant
CV
=2.54%
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
27
Appendix Table 7. Cocoon shell weight (g)
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 0.39
0.38
0.39
1.16
0.38
T2 0.38
0.34
0.34
1.06
0.35
T3 0.36
0.35
0.35
1.06
0.35
TOTAL 1.13 1.07 1.08 3.28 0.36
ANALYSIS OF VARIANCE
SOURCE OF
DEGREES
SUM OF
MEAN
COMPUTED
TABULATED F
VARIATION
OF
SQUARES
SUM OF
F
F
FREEDOM
SQUARES
0.05 F
0.01
Treatment 2 0.0022
0.0011 5.56* 5.15 10.92
Error 6 0.0012
0.0020
Total
8
0.0034
* - significant
CV =3.88%
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
28
Appendix Table 8. Cocoon shell percentage (%)
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 21.43
21.30
21.52
64.25
21.42
T2 21.39
19.06
18.55
59.00
19.67
T3 17.59
20.88
2057
59.04
19.68
TOTAL 60.41 61.24 6.64
182.29
20.25
ANALYSIS OF VARIANCE
SOURCE OF
DEGREES
SUM OF
MEAN
COMPUTED
TABULATED F
VARIATION
OF
SQUARES
SUM OF
F
F
FREEDOM
SQUARES
0.05 F
0.01
Treatment 2 6.0786
3.0393 1.63ns 5.15 10.92
Error 6
11.2095
1.8682
Total
8
17.2882
ns – not
significant
CV
=6.74%
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
29
Appendix Table 9. Mortality rate (%)
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 3
3
4
10
3.33
T2 5
3
3
11
3.67
T3 3
5
8
16
5.33
TOTAL 11 11 15 37 4.11
ANALYSIS OF VARIANCE
SOURCE OF
DEGREES
SUM OF
MEAN
COMPUTED
TABULATED F
VARIATION
OF
SQUARES
SUM OF
F
F
FREEDOM
SQUARES
0.05 F
0.01
Treatment 2 6.8888
3.4494 1.29ns 5.15 10.92
Error 6
16.0000
2.6666
Total
8
22.8888
ns – not
significant
CV
=39.72%
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
30
Appendix Table 10. Cocoon filament length (m)
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 1,085.00
1,220.67
1,206.33
3,512.00
1170.67
T2 1,039.00
1,032.00
1,001.00
3,072.00
1,024.00
T3 1,008.33
1,035.33
946.67
2,990.33
996.78
TOTAL 3,132.33
3,288.00
3,154.00
9,574.33
1,063.81
ANALYSIS OF VARIANCE
SOURCE OF
DEGREES
SUM OF
MEAN
COMPUTED
TABULATED F
VARIATION
OF
SQUARES
SUM OF
F
F
FREEDOM
SQUARES
0.05 F
0.01
Treatment 2 52489.95
26244.97
9.81* 5.15 10.92
Error 6
16059.50
2676.58
Total
8
68549.45
* -significant
CV =0.72%
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
31
Appendix Table 11. Thickness of the cocoon filament length (Denier)
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 3.54
3.54
3.50
10.58
3.52
T2 3.52
3.47
3.47
10.46
3.48
T3 3.44
3.43
3.47
10.34
3.44
TOTAL 10.50 10.44 10.44
31.35 3.48
ANALYSIS OF VARIANCE
SOURCE OF
DEGREES
SUM OF
MEAN
COMPUTED
TABULATED F
VARIATION
OF
SQUARES
SUM OF
F
F
FREEDOM
SQUARES
0.05 F
0.01
Treatment 2 0.0096
0.0048 8.0* 5.15 10.92
Error 6 0.0036
0.0006
Total
8
0.0132
* -significant
CV =0.70%
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
LUIS, LEILA P. MAY 2007. Effect of Rust-Infected Mulberry Leaves Fed to
PTRI SW-3 Hybrid Silkworm (Bombyx mori L.) on the Quality of Cocoon Yield in La
Trinidad, Benguet. Benguet State University, La Trinidad, Benguet.
Adviser: Valentino L. Macanes, MSc
ABSTRACT
The study was conducted to determine the effect of mulberry leaves infected by
rust fed to hybrid silkworms (PTRI SW-3) on the quality and quantity of cocoons
produced and to evaluate the susceptibility of silkworms (PTRI SW-3) fed with rust-
infected mulberry leaves (Batac var.) to silkworm diseases.
Results of this study revealed no significant effect rust-infected mulberry leaves
fed to silkworms on larval duration, whole cocoon weight, cocoon shell percentage and
mortality rate. However, moderate and severe rust infection to mulberry leaves affected
the raw silk properties of cocoons. Slight rust-infected mulberry leaves fed to hybrid
silkworms had the highest mean on the number of good cocoons produced with a low
number of defective cocoons. This was followed by silkworms fed with moderately rust-
infected mulberry leaves. Meanwhile, the silkworms fed with mulberry leaves that were
severely infected with mulberry rust produced the lowest number of good cocoons with a
high number of defective cocoons. In addition, undernourished silkworm larvae were also
observed in this treatment and these silkworms were not able to spin cocoons.
No silkworm disease occurrence was observed during the period of the study.
TABLE OF CONTENTS
Page
Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
i
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
i
Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ii
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
REVIEW OF LITERATURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
MATERIALS AND METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5
RESULTS AND DISCUSSION
Larval Duration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10
Number of Good Cocoons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11
Number of Defective Cocoons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11
Number of Good Cocoons Contained
in a One (1) Liter Cylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12
Weight of Good Cocoons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
Weight of Whole Cocoon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13
Weight of Cocoon Shell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14
Cocoon Shell Percentage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
Mortality Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15
Cocoon Filament Length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16
Thickness of the Cocoon Filament . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17
SUMMARY, CONCLUSION AND RECOMMENDATION . . . . . . . . . . . . . .
18
LITERATURE CITED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20
APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21
ii
1
INTRODUCTION
Rust is one of the most important diseases affecting mulberry plants. This maybe
caused by either Aecidium mori or Cerotelium fici. Both pathogens belong to Order
Urticales of Class Basidiomycetes. The A. mori affects the leaves, petioles, tender buds
and even fruits. On the other hand, C. fici affects the leaves only. Rust reduces the
nutritional value needed by the silkworms (Bugnay, 1995).
The quality and suitability of the mulberry foliage have direct effect on both the
vitality of the silkworm and the yield, quality of cocoons and quality of silk filaments,
therefore, must be taken in choosing the best quality of leaves to be able to meet the
requirements of the different growing stage of silkworm larvae particularly in the young
ages. At the same time quantity of mulberry leaves must be provided to maintain regular
growth (Pang-chuan et al., 1986).
The choice of mulberry leaves as the sole food suitable to the age and growth of
the silkworm larvae is one of the most important considerations in sericulture. Leaves for
young ages (1st –3rd instars) must be soft, succulent, rich in protein, carbohydrates and
minerals. While for the grown up stage (4th –5th instars) wherein the silk glands are being
developed leaves must be rich in protein and fiber (Balingan, 1994).
Krishnawasmi (1973) found that starvation and underfeeding of worms lead to
poor growth and weakening which leads to susceptibility of silkworms to diseases. If the
larval stage is prolonged, this indicates that rearing is not suitable. Therefore, the rearer
must be accurate in feeding the desired number of worms so that the leaves given will be
fully utilized. He further discovered that the adequacy of feeds minimizes prolonged
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
2
larval duration and undernourished silkworms whose effects results to poor quality and
quantity of cocoons produced.
On the other hand, Celis (1997) stated that mulberry silkworms are fed three (3)
times a day. Feeding them in proper time and giving the right quality of leaves contribute
greatly to success of cocoon quality.
Silkworms are affected by various types of diseases. These include infection by
pathogenic microorganisms like viral diseases, bacterial diseases, fungal diseases and
protozoan infection. Likewise, the physiology of silkworms is easily affected by
environmental factors such as weather conditions, technique of rearing, quality of
mulberry feed and silkworm variety (Veda et al., 1997).
Thus this study was conducted to serve as a guide for students, researchers, and
farmers who are presently engaged in sericulture and for those who intend to go into
sericulture production. This study will help in choosing the quality of mulberry leaves to
be fed to silkworms to avoid profit loss. In addition, the study aimed to determine the
effect of mulberry leaves infected by rust fed to hybrid silkworms (PTRI SW-3) on the
quality and quantity of cocoons produced and to evaluate the susceptibility of silkworms
(PTRI SW-3) fed with rust-infected mulberry leaves (Batac var.) to silkworm diseases.
This study was conducted at the Benguet State University Sericulture Project
located at Ampasit, Puguis, La Trinidad, Benguet and the Philippine Textile Research
Institute (PTRI) Laboratory, Km. 6, La Trinidad, Benguet from January to May 2007.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
3
REVIEW OF LITERATURE
Mulberry tree (Morus spp.) belongs to the family Moraceae of genus Morus. It is
the sole food of silkworms (Bombyx mori L.) (Bugnay, 1995). However, the plants are
affected by several types of diseases. There are about twenty (20) diseases which usually
attack mulberry plants that needs careful preventive measures and some of these includes
fungus, bacteria, mycoplasma, and viruses. Most of the diseases are infectious and affects
either the entire plant or selectively the roots, stems and leaves (Veda et. al., 1997).
Diocares (1978) as cited by Cawa-it (2006) stated that rust-infected plants show
increase water loss because they transpire more water through ruptured dermis. In
addition, the fungus competes with the plants by absorbing more nutrients and water.
Likewise, the photosynthesis of the plants is considerably reduced. Furthermore, UNDP-
ESCAP (1999) stated that mulberry rust causes 90-100% damage to mulberry plants.
Besides, rust-infected mulberry leaves affects the nutrition of the mulberry silkworms.
Inferior quality cocoons maybe produced from silkworms fed with low quality of
mulberry leaves.
Silkworms are stenophagous insects that feeds on mulberry leaves. Their life
cycle is completed by passing through four (4) stages; egg, larva, pupa and adult (moth).
At the pupal stage, the body is defenseless against external enemies hence the silkworm
larvae spins a protective shell around its body called cocoons. These are made up of
silkfibers which is secreted from a pair of silkgland extruded through the silkworms
spinneret. In sericulture, the larvae are killed in the cocoon after several days of spinning.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
4
Killing is done either by steam or hot air. This procedure is done to soften the sericin for
easy filament winding (Veda et. al., 1997).
Diocares (1978) observed that young silkworm larvae require different diet in
comparison with that of the later stages. Young larvae needs comparatively soft,
succulent leaves with less starch and fiber. On the other hand, the mature larvae requires
high protein and carbohydrate content but les moisture. He also reported that proper
nutrient coupled with proper time of feeding and rearing techniques are necessary in
obtaining high quality and quantity of silk.
Celis (1997) stated that attention must be given to ensure that the quality of
harvested mulberry leaves is maintained. Mulberry leaves should be stored in cool place
and out of direct sunlight, polyethylene and wet cloth sheet maybe used to provide cool
temperature and high humidity. Leaves not well kept easily wilts, that which helps
reduces silkworms feeding appetite.
Delayed feeding of mulberry silkworm affects the physiological functioning of
their body. Hence, the growth rate of the worms is hindered. Starvation leads to poor and
weakening of the worms. The worms ultimately becomes susceptible to diseases since
prolonged larval duration of the different instars leads to poor growth of the latter stage
and poor development of silkglands (Krishnawasmi, 1973).
Meanwhile, Pang-chuan et al. (1986) stated that water content of leaves losses
more than 10% of its original weight. They further found that because of this the appetite
of the silkworms will significantly lessen. If it losses more than 30%, the consumption of
the mulberry leaves will decrease to less than half of the quantity of the food stuff and
under ordinary conditions, silkworms will refuse to eat.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
5
MATERIALS AND METHODS
The important materials used in the study were as follows: PTRI SW-3 hybrid
mulberry silkworm (Bombyx mori L.) and mulberry leaves (Batac variety). The mulberry
leaves were classified as follows: slightly rust-infected, moderately rust-infected, and
severely rust-infected. The other materials and equipment included: power sprayer,
rearing trays, rearing stands, weighing scale, heater, thermohygrometer, cocooning frame,
knife, chopping board, cleaning nets, paraffin paper, news papers, pruning shear,
mulberry baskets, wet cloth, and data sheets. The chemicals used were: formalin (3%),
powdered lime, disinfectant soap and rubbing alcohol (75%)
Nine hundred newly-hatched hybrid silkworm larvae of PTRI SW-3 were reared
in the rearing house and were fed with different quality of Batac mulberry leaves. The
study was conducted using the simple Completely Randomized Design (CRD) with three
(3) treatments each replicated three (3) times. The study used the percentage rate scale for
mulberry rust infection rating as recommended by Subba Rao et al. (1991) as cited by
Strange (1993). The treatments were the following:
Treatment Leaf
Quality
Disease Severity Rating
1 Slight
Rust
Infection
1-25%
2
Moderate Rust Infection
26-75%
3 Severe
Rust
Infection
76-100%
Rearing of silkworm was conducted following the rearing procedure
recommended by the Philippine Textile Research Institute (PTRI) as adapted by the
Benguet State University (BSU) Sericulture Project at Puguis, La Trinidad, Benguet.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
6
Rearing house disinfection. Before rearing started, the room and implements were
cleaned, washed and dried. The 3% formalin solution were prepared. The solution was
sprayed to the rearing room using the power sprayer, After spraying, the rearing room
was tightly closed for 24 hours to ensure effective disinfection. This was done ten (10)
days before brushing. Disinfection is effective at higher temperature thus, it was done at
11:00 am. The other implements these were soaked in 2% formalin solution and sun
dried.
Brushing. Newly-hatched silkworm larvae were separated from their shells by
placing finely chopped mulberry leaves over them. Afterwards, it was transferred in a
clean rearing tray by brushing the worms with the use of white, clean feather.
Feeding. Feeding was done three (3) times a day respectively; at 7:00 am, 1:00
pm and 6:00 pm. Young ages (1st to 3rd instar larvae) were fed with finely-chopped
mulberry leaves taken near the shoot. On the other hand, the grown-up stage (4th to 5th
instar larvae) were fed with the whole mature leaves.
Bed cleaning. Bed cleaning was done using nets placed on top of the rearing tray
with finely chopped mulberry leaves for the young ages. On the other hand, whole mature
leaves for the grown-up stage were placed on top of the rearing tray over the worms. The
net was lifted when all the larvae have crawled up, and is transferred to a separate tray.
This was done to prevent accumulation of uneaten mulberry leaves, fecal matters and
dead larvae that would eventually ferment and produce poisonous gas that affect the
silkworms.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
7
Bed spacing. The silkworms in the rearing bed were regularly spread to prevent
overcrowding that may cause irregular growth and even susceptibility to diseases. This
was done using a clean bird feather or chopstick.
Mounting. Matured silkworm larvae were picked from the rearing trays and were
mounted on the rotary mounting frame. Cocoon harvesting was done seven days after
mounting.
Cocoon harvesting. Harvesting of the cocoons was done seven days after
mounting. Harvested cocoons were deflossed and sorted, respectively, in each treatment
replications.
All the required temperature and room humidity for each instars strictly followed
during the silkworm rearing.
The data gathered were:
1. Larval duration. This was taken by counting the number of days from hatching
to mounting.
2. Cocoon yield quality. Harvested cocoons were deflossed, sorted and were
evaluated per treatment replicate using the following parameters:
a. Number of good cocoons. This was gathered by counting the number of good
cocoons produced per treatment replicate.
b. Number of defective cocoons. This was taken by counting the number of
defective cocoons which include the following: double, perforated, malformed, fluffy,
thin end stained dead cocoons.
c. Number of good cocoons contained per one (1) liter cylinder. This was
measured by counting the number of good cocoons contained in a one (1) liter cylinder.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
8
d. Cocoon weight (g). This was measured by weighing the good cocoons using
the weighing scale.
e. Whole cocoon weight (g). This was gathered by weighing five sample good
cocoons using the Mettler’s Balance. The samples were randomly picked from the
treatment replicates.
f. Cocoon shell weight (g). This was taken by cutting the five sample good
cocoons used in getting the whole cocoon weight. The pupae and exuviae were removed,
afterwhich, cocoon shell of the five sample cocoons were weighed. The average cocoon
shell weight was taken using the following formula:
Weight of sample cocoons
CSW =
5
g. Cocoon shell percentage (%). This was taken from the five sample good
cocoons using this formula:
Weight of cocoon shell x 100
CSP =
Weight of whole cocoon
3. Mortality rate (%). This was taken by counting the number of dead larvae from
each treatment replicate from hatching to the mounting of the silkworms. This was taken
using the following formula:
Number of diseased/dead larvae x 100
MR =
Number of worms per replicate
4.Rawsilk
properties. This was evaluated using the following parameters:
a. Length of cocoon filament (m). This was measured by reeling three sample
cocoons per treatment replicate in an epprovette.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
9
b. Thickness of the filament (Denier). This was gathered by weighing the silk
bave. Afterwhich, it was solved using the following formula:
Weight of silk bave x 9000m
Denier =
Length of rawsilk
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
10
RESULTS AND DISCUSSION
Larval Duration
Table 1 shows no significant differences on the number of the days that the
silkworm (PTRI SW-3) had completed their larval stage. All the three treatments showed
the same mean of 29 days.
.Table 1. Larval duration of the PTRI SW-3 fed with rust- infected mulberry leaves.
TREATMENT MEAN
(days)
1 – Slight rust infection
29
2 – Moderate rust infection
29
3 – Severe rust infection
29
Means with the same letter are not significantly different at 5% level using DMRT
Number of Good Cocoons
Table 2 shows the number of good cocoons produced from each treatment.
Statistical analysis revealed that there was a highly significant differences among the
treatments. The silkworms fed with mulberry leaves slightly infected by rust (T1) had the
highest mean which is 83.67 followed by silkworms fed with leaves moderately infected
with rust (T2) with a mean of 75.00. On the other hand, Treatment 3, (silkworms fed with
mulberry leaves severely infected by rust) gave the lowest mean of 66.67.
. This signifies that the quality of mulberry leaves fed to the silkworms greatly
affected the number of good cocoons produced. Results of the study confirms the
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
11
findings of UNDP-ESCAP (1999) that inferior quality of cocoons maybe produced from
silkworms fed with disease infected mulberry leaves.
Table 2. Number of good cocoons obtained from the different rust- infected mulberry
leaves
TREATMENT MEAN
1 – Slight rust infection
83.69a
2 – Moderate rust infection
75.00b
3 – Severe rust infection
66.67c
Means with the same letter are not significantly different at 5 % level using DMRT
Number of Defective Cocoons
The number of defective cocoons harvested from each treatment replicate is
presented in Table 3. Statistical analysis revealed that there was a highly significant
differences among the treatments. Treatment 3, (silkworms fed with mulberry leaves
having severe rust-infection) gave the highest mean of 83.33 defective cocoons followed
by the Treatment 2, (silkworms fed with mulberry leaves having moderate rust infection)
with a mean of 21.33 defective cocoons. Finally, Treatment 1 (silkworms fed with
mulberry leaves having slight rust infection) gave the lowest mean of 13.00 defective
cocoons.
This study affirms the discovery of Pang-chuan et al. (1986) that the quality and
suitability of mulberry foliage have direct effect on both the vitality of silkworm and the
quality of cocoons produced.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
12
Table 3. Number of defective cocoons obtained from the treatments fed with rust –
infected mulberry leaves
TREATMENT MEAN
1 – Slight rust infection
13.00c
2 – Moderate rust infection
21.33b
3 – Severe rust infection
28.33a
Means with the same letter are not significantly different at 5 % level using DMRT
Number of Good Cocoons Contained
in a One (1) Liter Cylinder
Table 4 shows the number of good cocoons contained in a one (1) liter cylinder.
Statistical analysis showed highly significant differences. Treatment 3 gave the highest
mean number of good cocoons contained in one liter cylinder with 94.67, followed by
Treatment 2 with 91.33. Finally, Treatment 1 gave the lowest mean of good cocoons in
one liter cylinder with 78.67.
This finding implies that the quality of mulberry leaves fed to silkworms affected
the cocoon size produced from each treatment. Slight rust infection of mulberry leaves
produce bigger cocoon size while severe rust infection of mulberry leaves produce
smaller size of cocoons
Table 4. Number of good cocoons contained in a 1 liter cylinder taken from mulberry
PTRI SW-3 fed with rust -infected mulberry leaves
TREATMENT MEAN
1 – Slight rust infection
78.67b
2 – Moderate rust infection
91.33a
3 – Severe rust infection
94.67 a
Means with the same letter are not significantly different at 5 % level using DMRT
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
13
Weight of Good Cocoons
The weight of good cocoons is presented in Table 5. Results showed that there
was highly significant differences among the treatments as found by statistical analysis.
Treatment 1 gave the highest mean weight of good cocoons with 140.180 grams, while
Treatment 2 had 113.573 grams. Finally, Treatment 3 gave the lowest mean of good
cocoons with 100.83grams.
Table 5. Weight of good cocoons per replicate harvested from PTRI SW-3 fed rust –
infected mulberry leaves
TREATMENT MEAN
(g)
1 – Slight rust infection
140.180 a
2 – Moderate rust infection
113.573b
3 – Severe rust infection
100.083b
Means with the same letter are not significantly different at 5 % level using DMRT
Weight of Whole Cocoon
Table 6 shows the whole cocoon weight produced by silkworms fed with different
quality of mulberry leaves. Statistical analysis showed no significant differences on the
PTRI SW-3 silkworms fed with the rust–infected mulberry leaves. However, the
silkworms fed with leaves having slight rust infection (T1) recorded the highest mean of
1.80 grams followed by the silkworms fed with leaves having moderate rust infection
(T2) with a mean of 1.79. Finally, the silkworms fed with leaves having severe rust
infection (T3) gave the lowest mean of 1.75 grams.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
14
Table 6. Whole cocoon weight produced by PTRI SW-3 fed with rust-infected mulberry
leaves
TREATMENT MEAN
(g)
1 – Slight rust infection
1.80
2 – Moderate rust infection
1.79
3 – Severe rust infection
1.75
Means with the same letter are not significantly different at 5 % level using DMRT
Weight of Cocoon Shell
The cocoon shell weight obtained from each treatment is shown in Table 7.
Statistical analysis found significant differences among the different treatments.
Treatment 1 had the highest mean cocoon shell weight of 0.38 grams while both
Treatments 2 and 3 gave the same mean of 0.35 grams cocoon shell weight.
This result proves that Treatment 1 (slightly rust-infected mulberry leaves fed to
silkworms) produced better cocoon quality than that of the moderate and severely rust-
infected leaves.
Table 7. Cocoon shell weight taken from PTRI SW-3 fed with rust-infected mulberry
leaves
TREATMENT MEAN
(g)
1 – Slight rust infection
0.38 a
2 – Moderate rust infection
0.35 b
3 – Severe rust infection
0.35 b
Means with the same letter are not significantly different at 5 % level using DMRT
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
15
Cocoon Shell Percentage
Table 8 shows the cocoon shell percentage taken from the different treatments.
Statistically, no significant differences among the treatments. However, Treatment 1 gave
the highest mean of 21.41% cocoon shell percentage, while Treatment 2 gave a mean of
19.68%. Finally, Treatment 3 gave the lowest mean of 19.67% cocoon shell percentage.
Table 8. Cocoon shell percentage taken from the PTRI SW-3 fed with rust-infected
mulberry leaves
TREATMENT MEAN
(%)
1 – Slight rust infection
21.41
2 – Moderate rust infection
19.68
3 – Severe rust infection
19.67
Means with the same letter are not significantly different at 5 % level using DMRT
Mortality Rate
Table 9 presents the mortality rate of the silkworms fed with the different rust
infection of mulberry leaves. Statistical analysis shows no significant differences among
the treatments. However, Treatment 3 gave the highest mean of 5.33% mortality rate and
Treatment 2 had a mean of 3.66 %. Treatment 1 gave the lowest mortality rate with a
mean of 3.33%.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
16
Table 9. Mortality rate obtained from the different percentage of PTRI SW-3 fed with
rust-infected mulberry leaves
TREATMENT MEAN
(%)
1 – Slight rust infection
3.33
2 – Moderate rust infection
3.66
3 – Severe rust infection
5.33
Means with the same letter are not significantly different at 5 % level using DMRT
Cocoon Filament Length
The filament length gathered from the different treatments is presented in Table
10. Significant difference among the treatments was observed as revealed by statistical
analysis. The highest mean filament length was obtained from Treatment 1 (silkworms
fed with mulberry leaves slightly-infected with rust) which gave 1170.67 meters. This
was followed by Treatment 2 (silkworms fed with mulberry leaves moderately-infected
with rust) with a mean of 1,024.00 meters. Finally, Treatment 3 (silkworms fed with
mulberry leaves severely-infected with rust) gave the lowest mean of 996.78 meters
cocoon filament length.
The quality of silk filament was greatly affected by quality of mulberry leaves
given to silkworms.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
17
Table 10. Cocoon filament length produced by PTRI SW-3 fed with rust infected
mulberry leaves
TREATMENT MEAN
(m)
1 – Slight rust infection
11.70.67 a
2 – Moderate rust infection
1024.00 ab
3 – Severe rust infection
996.78 b
Means with the same letter are not significantly different at 5 % level using DMRT
Thickness of the Cocoon Filament
The thickness of cocoon filament is shown in Table 11. Statistical analysis
showed that there were significant differences among the treatments. The silkworms fed
mulberry leaves slightly-infected with rust (T1) produced the thickest filament with 3.52
denier followed by Treatment 2 (moderate rust infection) with a mean of 3.48 denier.
Finally, the silkworms fed with mulberry leaves with severe rust infection (T3) gave the
lowest denier size of 3.44.
Table 11. Thickness of the cocoon filament harvested from the PTRI SW-3 fed with rust-
infected mulberry leaves
TREATMENT MEAN
(Denier)
1 – Slight rust infection
3.52 a
2 – Moderate rust infection
3.48 ab
3 – Severe rust infection
3.44 b
Means with the same letter are not significantly different at 5 % level using DMRT
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
18
SUMMARY, CONCLUSION AND RECOMMENDATION
Summary
The study was conducted to determine the effect of rust – infected mulberry
leaves fed to hybrid silkworms (PTRI SW-3) on the quality and quantity of cocoons
produced. Likewise, it was done to evaluate the susceptibility of silkworms (PTRI SW-3)
to silkworm diseases when fed with rust - infected mulberry leaves The parameters used
in evaluating the effect of rust-infected mulberry leaves were: larval duration, cocoon
yield quality particularly, number of good cocoons, number of defective cocoons, number
of good cocoons contained in one (1) liter cylinder, whole cocoon weight, cocoon shell
weight, cocoon shell percentage and larval mortality rate. Raw silk properties were also
taken, specifically, on the length of cocoon filament and the size of cocoon filament.
Hybrid silkworm PTRI SW-3 was used in the study. The silkworm was fed with
different quality of mulberry leaves classified as: slight rust infection (T1), moderate rust
infection (T2), and severe rust infection (T3).
Nine hundred (900) silkworm larvae were reared at Benguet State University
Sericulture Project located at Puguis, La Trinidad, Benguet from hatching to cocoon
harvesting. The standard silkworm rearing procedure was strictly followed. The harvested
cocoons were assessed at Philippine Textile Research Institute Laboratory located at Km.
6, Betag, La Trinidad, Benguet. The study was conducted from January to May 2007.
The study used Completely Randomized Design (CRD).
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
19
The results of the study found that there were highly significant differences
observed on the PTRI SW-3 hybrid silkworm on the number of good cocoons, number of
defective cocoons, number of good cocoons contained in one (1) liter cylinder and the
weight of good cocoons per replicate, when fed with rust-infected mulberry leaves. The
silkworms fed with mulberry leaves slightly infected with rust gave the best cocoon
quality and raw silk properties. This was followed by silkworms fed with mulberry leaves
moderately infected by rust. Finally, the PTRI SW-3 hybrid silkworms fed with mulberry
leaves severely infected with rust gave the lowest cocoon quality and raw silk properties.
However, no significant differences were taken on the following parameters: larval
duration, whole cocoon weight, cocoon shell percentage and mortality rate.
Conclusion
The result of the study showed that the hybrid mulberry silkworm (PTRI SW-3)
fed with slightly rust-infected mulberry leaves produce the best quality of good cocoons
compared with the other treatments.
Recommendation
The results of this study recommend that the percentage of rust infection to
mulberry leaves to be fed to hybrid silkworms should be taken into consideration in
silkworm rearing. Mulberry leaves with severe rust infection should not be utilized for
silkworm rearing. However, this experiment should also be tried in rearing pure breed
silkworms. Likewise this study should be done also in other locations and silkworm
rearing seasons.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
20
LITERATURE CITED
BALINGAN, S. 1994. Evaluation of the larval development and cocoon quality of four
F1 hybrid silkworms (Bombyx mori L.) in Benguet. BS Thesis. Benguet State
University, La Trinidad, Benguet. P. 5.
BUGNAY, L. B. 1995. Performance of silkworm (Bombyx mori L.) fed with mulberry
leaves sprayed with fungicides. BS Thesis. Benguet State University, La Trinidad,
Benguet. Pp. 1-4.
CAWA-IT, E. B. 2006. Field efficacy of fungicides for the control of mulberry red rust
(Aecidium mori B.) in La Trinidad. BS Thesis. Benguet State University, La
Trinidad, Benguet. Pp. 4-6.
CELIS, S. P. 1997. Influence of different methods of storing mulberry leaves on the
cocoon yield of JC 102 silkworm variety. BS Thesis. Benguet State University,
La Trinidad, Benguet. Pp. 3-5.
DIOCARES, C. 1978. Comparative effects of feeding frequency on a strain of silkworm
(Bombyx mori L.). BS Thesis. Benguet State University, La Trinidad, Benguet. P.
4.
KRISHNAWASMI, S. R. 1973. Silkworm feeding trials for evaluating the quality of
mulberry leaves as influenced by variety, spacing and nitrogen fertilization.
Biological abstract. Pp. 10, 79 and 89.
PANG-CHUAN, W. H. GUANG-XIAN, M. MABEN AND T. YUN-FANG. 1986.
Mulberry Cultivation. Food Agricultural Organization. Agricultural Services
Bulletin. Rome. Pp. 99-101.
STRANGE, R. N. 1993. Plant Disease Control. First Edition. Chapman and Hall.
Boundary Row, London, England. P. 94.
UNITED NATIONS DEVELOPMENT PROGRAM - ECONOMIC AND SOCIAL
COMMISSION FOR ASIA AND THE PACIFIC. 1999. Handbook on Mulberry
Pest and Diseases. UNDP-ESCAP. Bangkok, Thailand. Pp. 89-93.
VEDA, K., I. NAGAI, AND M. HORIKOMI. 1997. Silkworm Rearing. Science
Publishers Incorporation. U.S.A. Pp. 1 and 90.
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
21
APPENDICES
Appendix Table 1. Larval duration (days)
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 29
29
29
87
29
T2 29
29
29
87
29
T3 29
29
29
87
29
TOTAL 87 87 87 261 87
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
22
Appendix Table 2. Number of good cocoons
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 85
82
84
251
83.667
T2 75
78
72
225
75.000
T3 68
67
65
200
66.667
TOTAL 228 227 221 676
75.111
ANALYSIS OF VARIANCE
SOURCE OF
DEGREES
SUM OF
MEAN
COMPUTED
TABULATED F
VARIATION
OF
SQUARES
SUM OF
F
F
FREEDOM
SQUARES
0.05 F
0.01
Treatment 2 433.5555
216.7777
47.59** 5.15 10.92
Error 6
27.3333
4.5555
Total
8
460.8888
**
highly
significant
CV
=
2.84%
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
23
Appendix Table 3. Number of defective cocoons
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 12
15
12
39
13
T2 20
19
25
64
21.33
T3 30
28
27
85
28.33
TOTAL 62 62 64 188
20.88
ANALYSIS OF VARIANCE
SOURCE OF
DEGREES
SUM OF
MEAN
COMPUTED
TABULATED F
VARIATION
OF
SQUARES
SUM OF
F
F
FREEDOM
SQUARES
0.05 F
0.01
Treatment 2 353.5555
176.7777
33.85** 5.15 10.92
Error 6
31.3333
5.2222
Total
8
384.8888
** highly significant
CV = 10.43%
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
24
Appendix Table 4. Number of good cocoons contained in a 1 liter cylinder
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 80
76
80
236
78.67
T2 92
90
92
272
90.67
T3 98
96
90
284
94.67
TOTAL 270 262 262 792
88.00
ANALYSIS OF VARIANCE
SOURCE OF
DEGREES
SUM OF
MEAN
COMPUTED
TABULATED F
VARIATION
OF
SQUARES
SUM OF
F
F
FREEDOM
SQUARES
0.05 F
0.01
Treatment 2 427.5555
213.7777
26.72** 5.15 10.92
Error 6
48.0000
8.0000
Total
8
475.5555
**
highly
significant
CV
=
3.20%
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
25
Appendix Table 5. Weight of good cocoons per replicate (g)
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 148.16
135.69
136.69
420.54
140.18
T2 116.28
122.38
102.06
340.72
113.57
T3 97.85
99.40
103.00
300.25
100.08
TOTAL 362.29
357.47
341.75
1,061.51
117.94
ANALYSIS OF VARIANCE
SOURCE OF
DEGREES
SUM OF
MEAN
COMPUTED
TABULATED F
VARIATION
OF
SQUARES
SUM OF
F
F
FREEDOM
SQUARES
0.05 F
0.01
Treatment 2 2497.6374 124.88187
22.88** 5.15 10.92
Error 6
327.4225
54.5704
Total
8
2825.0600
**
highly
significant
CV
=
6.26%
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
26
Appendix Table 6. Whole cocoon weight (g)
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 1.82
1.78
1.81
5.41
1.80
T2 1.78
1.78
1.83
5.39
1.80
T3 1.82
1.68
1.75
5.25
1.75
TOTAL 5.42 5.24 5.39
16.05
5.35
ANALYSIS OF VARIANCE
SOURCE OF
DEGREES
SUM OF
MEAN
COMPUTED
TABULATED F
VARIATION
OF
SQUARES
SUM OF
F
F
FREEDOM
SQUARES
0.05 F
0.01
Treatment 2 0.0050
0.0025 1.23ns 5.15 10.92
Error 6 0.0123
0.0020
Total
8
0.0174
ns
-
not
significant
CV
=2.54%
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
27
Appendix Table 7. Cocoon shell weight (g)
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 0.39
0.38
0.39
1.16
0.38
T2 0.38
0.34
0.34
1.06
0.35
T3 0.36
0.35
0.35
1.06
0.35
TOTAL 1.13 1.07 1.08 3.28 0.36
ANALYSIS OF VARIANCE
SOURCE OF
DEGREES
SUM OF
MEAN
COMPUTED
TABULATED F
VARIATION
OF
SQUARES
SUM OF
F
F
FREEDOM
SQUARES
0.05 F
0.01
Treatment 2 0.0022
0.0011 5.56* 5.15 10.92
Error 6 0.0012
0.0020
Total
8
0.0034
* - significant
CV =3.88%
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
28
Appendix Table 8. Cocoon shell percentage (%)
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 21.43
21.30
21.52
64.25
21.42
T2 21.39
19.06
18.55
59.00
19.67
T3 17.59
20.88
2057
59.04
19.68
TOTAL 60.41 61.24 6.64
182.29
20.25
ANALYSIS OF VARIANCE
SOURCE OF
DEGREES
SUM OF
MEAN
COMPUTED
TABULATED F
VARIATION
OF
SQUARES
SUM OF
F
F
FREEDOM
SQUARES
0.05 F
0.01
Treatment 2 6.0786
3.0393 1.63ns 5.15 10.92
Error 6
11.2095
1.8682
Total
8
17.2882
ns – not
significant
CV
=6.74%
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
29
Appendix Table 9. Mortality rate (%)
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 3
3
4
10
3.33
T2 5
3
3
11
3.67
T3 3
5
8
16
5.33
TOTAL 11 11 15 37 4.11
ANALYSIS OF VARIANCE
SOURCE OF
DEGREES
SUM OF
MEAN
COMPUTED
TABULATED F
VARIATION
OF
SQUARES
SUM OF
F
F
FREEDOM
SQUARES
0.05 F
0.01
Treatment 2 6.8888
3.4494 1.29ns 5.15 10.92
Error 6
16.0000
2.6666
Total
8
22.8888
ns – not
significant
CV
=39.72%
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
30
Appendix Table 10. Cocoon filament length (m)
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 1,085.00
1,220.67
1,206.33
3,512.00
1170.67
T2 1,039.00
1,032.00
1,001.00
3,072.00
1,024.00
T3 1,008.33
1,035.33
946.67
2,990.33
996.78
TOTAL 3,132.33
3,288.00
3,154.00
9,574.33
1,063.81
ANALYSIS OF VARIANCE
SOURCE OF
DEGREES
SUM OF
MEAN
COMPUTED
TABULATED F
VARIATION
OF
SQUARES
SUM OF
F
F
FREEDOM
SQUARES
0.05 F
0.01
Treatment 2 52489.95
26244.97
9.81* 5.15 10.92
Error 6
16059.50
2676.58
Total
8
68549.45
* -significant
CV =0.72%
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
31
Appendix Table 11. Thickness of the cocoon filament length (Denier)
TREATMENTS REPLICATION TOTAL
MEAN
1 2 3
T1 3.54
3.54
3.50
10.58
3.52
T2 3.52
3.47
3.47
10.46
3.48
T3 3.44
3.43
3.47
10.34
3.44
TOTAL 10.50 10.44 10.44
31.35 3.48
ANALYSIS OF VARIANCE
SOURCE OF
DEGREES
SUM OF
MEAN
COMPUTED
TABULATED F
VARIATION
OF
SQUARES
SUM OF
F
F
FREEDOM
SQUARES
0.05 F
0.01
Treatment 2 0.0096
0.0048 8.0* 5.15 10.92
Error 6 0.0036
0.0006
Total
8
0.0132
* -significant
CV =0.70%
Effect of Rust-Infected Mulberry Leaves Fed to PTRI SW-3 Hybrid Silkworm (Bombyx mori L.)
on the Quality of Cocoon Yield in La Trinidad, Benguet / Leila P. Luis. 2007
Document Outline
- Effect of Rust-Infected Mulberry Leaves Fed to
PTRI SW-3 Hybrid Silkworm (Bombyx mori L.) on the Quality of Cocoon Yield in La
Trinidad, Benguet
- BIBLIOGRAPHY
- ABSTRACT
- TABLE OF CONTENTS
- INTRODUCTION
- REVIEW OF LITERATURE
- MATERIALS AND METHODS
- RESULTS AND DISCUSSION
- SUMMARY, CONCLUSION AND RECOMMENDATION
- LITERATURE CITED
- APPENDICES