BIBLIOGRAPHY BUGTONG, MICHAEL W. MAY...
BIBLIOGRAPHY
BUGTONG, MICHAEL W. MAY 2012. Incidence and Severity of Rice Tungro
Virus in Sta. Cruz, Zambales. Benguet State University, La Trinidad, Benguet.
Adviser: Janet S. Luis, Ph.D.
ABSTRACT
This study was conducted to assess the incidence and severity of Rice Tungro Virus
in Sta. Cruz, Zambales.
Results in the field assessment revealed that infection occurred only in Tubo-tubo
South and Sabang.
Reported weeds alternate hosts, surveyed in six barangays of Sta. Cruz, Zambales
and found widespread in all assessed fields, furthermore, rice stubbles and volunteer rice
as a source of inoculums and alternate hosts of RTV was observed on infected fields.
In the interviews conducted, farmers observed yellowing and stunting of rice once
or twice a year especially during the rainy season when vector insects are observed.
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
RESULTS AND DISCUSSION
Rice TungroVirus Symptoms
Observed in Survey Areas
Several symptoms suspected to be caused by RTV were manifested by rice varieties
Rc 14 and Rc 18. These include yellow green to yellow color of leaves (Figure 1 and 2),
stunting (Figure 3) and stunting in combination with color change of leaves from green to
yellow-orange, mottling, with dark brown spot (Figure 4).
Figure 1. Rice variety Rc 14 at vegetative stage as observed
in Tubo-tubo South
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
Figure2. Rice variety Rc 14 showing yellow to yellow green
discoloration at reproductive stage
Figure 3. Rice variety Rc 18 showing stunting at reproductive
stage
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
Figure 4. Rice variety Rc 18 showing yellow and
stunting during reproductive stage
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
Rice TungroVirus Severity and
Incidence in Survey Areas
From the interviews conducted, farmers perceived the disease symptoms as feeding
damage by insects which they manage by chemical spraying as immediate remedy. Though
only two fields showed infection of RTV (Tubo-tubo South and Sabang), other farmers say
that they also observed yellowing and stunting of rice at least once or twice a year
especially during the rainy season when insects are observed, on the other hand the
characteristics that was planted during the assessment reported to be not resistant to tungro
virus.
Furthermore unlike other sites, affected fields and its surroundings are abundant
with rice stubbles and volunteer rice, where in Mukhopadhyay et al., 1986 report that it
could act as source of inoculums for the carryover of tungro especially under intensified
rice cropping systems with continuous planting like in Sta. Cruz, Zambales. The
assessment also recorded the ways of rice planting done by farmers where transplanting is
common whereseed is sown in one place and the seedlings after they have grown a little
are transplanted to another, this is done in order to get higher yields and less weeding.
Chancellor et al., 1996 reported that early immigration of leafhoppers into rice plots was
greatest in wet seasons (WS) and was also high in a late-planted dry season (DS) crop
which was out of synchrony with surrounding rice fields and the size population is not
directly related to the incidence of RTV unless inoculums pressure is taken into account
then secondary spread of the infection will occur.
Although no green leaf hopper was collected in the field due to the age of the rice
during the survey and collection of insect vector it does not mean that the vector is absent
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
Table 2. Severity and incidence of Rice Tungro Virus in the field
SURVEYED FARMER AREA GROWTH RICE RTV RTV
BARANGAY (m2) STAGE VAR. SEVERITY INCIDENCE
Tubo-tubo
B. Mehos
8,000 reproductive Rc 14 11.28%
36%
South
=5 severity
vegetative
Rc 14
Sabang
R. Torneto 20,000 reproductive Rc 18 11.42%
49%
=5 severity
L. Morilo
6,000 reproductive Rc 14
Biay
M. Morilo 10,500 reproductive Rc 28 none
none
O. Bernal
3,000 reproductive Triple 2 none
none
Naulo
R. Mendi 4,000 reproductive Rc 14 none
none
Bayto
L. Morilo 4,500 reproductive Rc 14 none
none
J. Moralde 22,000 reproductive Rc 28 none
none
R. Renante 13,000 reproductive Triple 2 none
none
Lucapon
S. Bibal 15,000 reproductive Rc 152 none
none
North
on the vegetative stage of the rice. Chancellor and Holt, 2008 reported that GLH vectors
prefer to feed on young rice plants and tend to migrate from old to younger and more
susceptible plants. From the observation and data recorded the possible caused of infections
within a field are; transplanted seedlings infected with viruses prior to transplanting by
GLH that acquired virus from infected stubbles and volunteer rice which is abundant on
the field where the infection observed and new growth from infected stubbles that had not
been properly plowed under and harrowed effectively.
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
Rice TungroVirus Weeds as Alternate
Hosts in Survey Areas
The different types of grasses which are alternate host for RTV that is find along
irrigation canals and widely spread on the rice fields assessed (Table 3).
From the observation, Echinochloa sp. is prevalent in the rice field which is present
in all barangays except in Naulo followed by Fimbristylis miliacea (L.) recorded in three
barangay and Eleusine indica in two barangay and lastly Leersia hexandra Sw. which
recorded in only one barangay, on the other hand Leersia hexandra Sw. is prevalent in
irrigation canals which is observed in all barangays except Tubo-tubo South and Eleusine
indica which is only observed in Naulo. In spite of the presence of weed alternate hosts of
tungro virus on the assessed area, other fields did not show infection of RTV. Tiongco et
al., 1993, reported that there was negative transmission of RTV from infected rice to the
reported weed alternate hosts. The result is not consistent with the earlier investigation
which reported positive detection of the virus on some weeds including Leersia hexandra
(Anjaneyulu et al., 1988; Parejarearn et al., 1990; Khan et al., 1991).
Aside as weeds, rice stubbles were also present. These rice stubbles can act as
reservoir for tungro viruses and the importance of volunteer rice as a source of tungro virus
and as a temporary refuge and source of food for the vectors in harvested fields.
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
Table 3. RTV weed alternate hosts found on the fields and along irrigation canals
WEED ALTERNATE PRESENCE IN PRESENCE IN
HOST RICE FIELD IRRIGATION CANALS
Tubo-tubo South
Fimbristylis miliacea (L.)
Echinochloa sp.
Sabang
Leersia hexandra Sw.
Fimbristylis miliacea (L.)
Echinochloa sp.
Eleusine indica
Leersia hexandra Sw.
Biay
Echinochloa sp.
Leersia hexandra Sw.
Naulo
Eleusine indica
Leersia hexandra Sw.
Bayto
Echinochloa sp.
Leersia hexandra Sw.
Eleusine indica
Lucapon North
Echinochloa sp. Leersia hexandra Sw.
Fimbristylis miliacea (L.)
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
Figure 5. Weed alternate host Eleusine indica along
irrigation canals
Figure 6. Weed alternate host Leersia hexandra Sw. in
the field with rice plant showing yellowing
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
Figure 7. Weed alternate host Fimbristylis miliacea (L.)
in the field
Figure 8. Weed alternate host Echinochloa sp. On field
with rice plant at vegetative stage
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
SUMMARY, CONCLUSION AND RECOMMENDATIONS
Summary
This study was conducted to assess the incidence and severity of RTV in Bayto,
Tubo-tubo South, Biay, Naulo, Sabang, and Lucapon North Sta. Cruz, Zambales based on
symptomatology.
Among the six barangays the presence of RTV was recorded in Sabang and Tubo-
tubo South Sta. Cruz Zambales. In spite of the absence of the insect vector, weeds which
are reported to be alternate hosts, rice stubbles and volunteer rice were present infields
infected with tungro virus.
Conclusion
The incidence and severity of RTV in Sta. Cruz, Zambales in the field during
summer are generally low. Nevertheless the data should not be overlooked noting that two
rice field, Tubo-tubo South and Sabang, showed symptoms, and that the four weed
alternate hosts, rice stubbles and volunteer rice were widespread in fields. Once the insect
vector Nephotettix virescens is available, the RTV can be transmitted from infected plants
to the healthy rice plants. It happened that the insect vector was not present during the
summer period and the early immigration is greatest during rainy season.
Recommendations
Further study should be done in the same field during rainy season when the vector
is present. In addition, a greenhouse study should be done to verify the efficiency of the
different weeds as alternate hosts, rice stubbles and volunteer rice to healthy plants.
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
LITERATURE CITED
AFUN, J. V. K., JOHNSON, D.E. and A. RUSSELL-SMITH.1999.Weeds and natural
enemy regulation of insect pests in upland rice; a case study from West Africa.
Bulletin of Entomological Research (1999), 89:391- 402 Cambridge
University Press.
ANONYMOUS, 2012. Institute of Medicine Retrieved May 20 from http://nutritiondata.
self. com
ANJANEYULU, A., DAQUIOAG, M. A., MESINA, E., HIBINO, H., LUBIGAN, R. T.
and K. MOODY. 1988. Host plant of rice tungro (RTV)-associated viruses. Intl.
Rice Res. Newsl. 13(4):30-31.
BAJET, N. B., AGUIERO, V. M., DAQUIOAG, R. D.,JONSON, G. B.,
CABUNAGAN, R. C.,MESINA,E. M., and H. HIBINO. 1986. Occurrence and
spread of rice tungro spherical virus in the Philippines. Plant Disease 70:971-973.
BOTTENBERG, S. A., BARRION, P. E., KENMORE, HLitsingerJa. 1990. Presence of
tungro vectors and their natural enemies in different rice habitats in
Malaysia. Agriculture, Ecosystems & Environment Volume 31, Issue 1, May
1990, Pp. 1-15.
CABAUATAN, P. Q., KOBAYASHI, N., IKEDA, R. and H.KOGANEZAWA.
1993. Oryza glaberrima: An indicator plant for rice tungro spherical
virus. International Journal of Pest Management, 39 (3): 273-276.
CHANCELLOR, C. B., COOK, A.G. and K.L. Heong. 1996. The within-field dynamics
of rice tungro disease relation to the abundance of its major leafhopper
vectors. Crop Protection, 15 (3): 439-449.
COOK, A. G. and T. J. PERFECT. 1989. Population dynamics of three
leafhopper vectors of rice tungro viruses, Nephotettix virescens (Distant), N.
nigropictu (Stål) and Recilia dorsalis (Motschulsky) (Hemiptera: Cicadellidae), in
farmers' fields in the Philippines. Bulletin of Entomological Research (1989),
79:437-451 Cambridge University Press.
COOTER, R. J., WINDER, D. andT.C.B.CHANCELLOR. 2000. Tethered flight activity
of Nephotettix virescens (Hemiptera: Cicadellidae) in the Philippines. Bulletin
of Entomological Research (2000), 90:49-55 Cambridge University Press.
KHAN, M. A., HIBINO, H., AGUERO, V. M. and R. D., DAQUIOAG. 1991. Rice and
weed hosts of rice-associated viruses and leafhopper vectors. Plant Dis. 75: 926-
930.
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
MOHANTY, S. K. and R. SRIDHAR. 2006. Physiology of rice tungro virus
disease: Proline accumulation due to infection. Physiological Planetarum, Volume
56 Issue1, Pp 89 – 93.
MUKHOPADHYAY, S., CHOWDURY, A. K. and S. K., CHAKRABARTY. 1986.
Epidemiology and control of rice tungro virus disease in West Bengal. Pp. 142-
153.
PAREJAREAN, A., CHETTANACHIT, D., PUTTA, M., RATTANAKARIN, W.,
ARAYAPAN, J. and S. DISTHAPORN. 1990. Hosts of rice tungro-associated
viruses (RTVs) in Thailand. Int. Rice Res. Newsl. 15(6): 21-22
NATH, N., MATHUR, S. and I. DASGUPTA. 2002. Molecular analysis of two complete
rice tungro bacilliform virus genomic sequences from India. Archives of
Virology, Volume 147, Number 6/June, 2002 1173-1187.
SRIDHAR, R., MOHANTY, S. K. and A. ANJANEYULU. 2006. Physiology of Rice
Tungro Virus Disease: Increased Cytokinin Activity in Tungro-Infected Rice
Cultivars. Physiologia Plantarum, Volume 43 Issue 4, Pp 363 – 366.
TIONGCO, E. R., FLORES, Z. M. and P. S., TENG. 1993. Inoculum sources of Rice
Tungro Viruses. Philipp. Phytopathol.Volume. 29: 30-41.
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
BUGTONG, MICHAEL W. MAY 2012. Incidence and Severity of Rice Tungro
Virus in Sta. Cruz, Zambales. Benguet State University, La Trinidad, Benguet.
Adviser: Janet S. Luis, Ph.D.
ABSTRACT
This study was conducted to assess the incidence and severity of Rice Tungro Virus
in Sta. Cruz, Zambales.
Results in the field assessment revealed that infection occurred only in Tubo-tubo
South and Sabang.
Reported weeds alternate hosts, surveyed in six barangays of Sta. Cruz, Zambales
and found widespread in all assessed fields, furthermore, rice stubbles and volunteer rice
as a source of inoculums and alternate hosts of RTV was observed on infected fields.
In the interviews conducted, farmers observed yellowing and stunting of rice once
or twice a year especially during the rainy season when vector insects are observed.
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
RESULTS AND DISCUSSION
Rice TungroVirus Symptoms
Observed in Survey Areas
Several symptoms suspected to be caused by RTV were manifested by rice varieties
Rc 14 and Rc 18. These include yellow green to yellow color of leaves (Figure 1 and 2),
stunting (Figure 3) and stunting in combination with color change of leaves from green to
yellow-orange, mottling, with dark brown spot (Figure 4).
Figure 1. Rice variety Rc 14 at vegetative stage as observed
in Tubo-tubo South
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
Figure2. Rice variety Rc 14 showing yellow to yellow green
discoloration at reproductive stage
Figure 3. Rice variety Rc 18 showing stunting at reproductive
stage
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
Figure 4. Rice variety Rc 18 showing yellow and
stunting during reproductive stage
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
Rice TungroVirus Severity and
Incidence in Survey Areas
From the interviews conducted, farmers perceived the disease symptoms as feeding
damage by insects which they manage by chemical spraying as immediate remedy. Though
only two fields showed infection of RTV (Tubo-tubo South and Sabang), other farmers say
that they also observed yellowing and stunting of rice at least once or twice a year
especially during the rainy season when insects are observed, on the other hand the
characteristics that was planted during the assessment reported to be not resistant to tungro
virus.
Furthermore unlike other sites, affected fields and its surroundings are abundant
with rice stubbles and volunteer rice, where in Mukhopadhyay et al., 1986 report that it
could act as source of inoculums for the carryover of tungro especially under intensified
rice cropping systems with continuous planting like in Sta. Cruz, Zambales. The
assessment also recorded the ways of rice planting done by farmers where transplanting is
common whereseed is sown in one place and the seedlings after they have grown a little
are transplanted to another, this is done in order to get higher yields and less weeding.
Chancellor et al., 1996 reported that early immigration of leafhoppers into rice plots was
greatest in wet seasons (WS) and was also high in a late-planted dry season (DS) crop
which was out of synchrony with surrounding rice fields and the size population is not
directly related to the incidence of RTV unless inoculums pressure is taken into account
then secondary spread of the infection will occur.
Although no green leaf hopper was collected in the field due to the age of the rice
during the survey and collection of insect vector it does not mean that the vector is absent
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
Table 2. Severity and incidence of Rice Tungro Virus in the field
SURVEYED FARMER AREA GROWTH RICE RTV RTV
BARANGAY (m2) STAGE VAR. SEVERITY INCIDENCE
Tubo-tubo
B. Mehos
8,000 reproductive Rc 14 11.28%
36%
South
=5 severity
vegetative
Rc 14
Sabang
R. Torneto 20,000 reproductive Rc 18 11.42%
49%
=5 severity
L. Morilo
6,000 reproductive Rc 14
Biay
M. Morilo 10,500 reproductive Rc 28 none
none
O. Bernal
3,000 reproductive Triple 2 none
none
Naulo
R. Mendi 4,000 reproductive Rc 14 none
none
Bayto
L. Morilo 4,500 reproductive Rc 14 none
none
J. Moralde 22,000 reproductive Rc 28 none
none
R. Renante 13,000 reproductive Triple 2 none
none
Lucapon
S. Bibal 15,000 reproductive Rc 152 none
none
North
on the vegetative stage of the rice. Chancellor and Holt, 2008 reported that GLH vectors
prefer to feed on young rice plants and tend to migrate from old to younger and more
susceptible plants. From the observation and data recorded the possible caused of infections
within a field are; transplanted seedlings infected with viruses prior to transplanting by
GLH that acquired virus from infected stubbles and volunteer rice which is abundant on
the field where the infection observed and new growth from infected stubbles that had not
been properly plowed under and harrowed effectively.
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
Rice TungroVirus Weeds as Alternate
Hosts in Survey Areas
The different types of grasses which are alternate host for RTV that is find along
irrigation canals and widely spread on the rice fields assessed (Table 3).
From the observation, Echinochloa sp. is prevalent in the rice field which is present
in all barangays except in Naulo followed by Fimbristylis miliacea (L.) recorded in three
barangay and Eleusine indica in two barangay and lastly Leersia hexandra Sw. which
recorded in only one barangay, on the other hand Leersia hexandra Sw. is prevalent in
irrigation canals which is observed in all barangays except Tubo-tubo South and Eleusine
indica which is only observed in Naulo. In spite of the presence of weed alternate hosts of
tungro virus on the assessed area, other fields did not show infection of RTV. Tiongco et
al., 1993, reported that there was negative transmission of RTV from infected rice to the
reported weed alternate hosts. The result is not consistent with the earlier investigation
which reported positive detection of the virus on some weeds including Leersia hexandra
(Anjaneyulu et al., 1988; Parejarearn et al., 1990; Khan et al., 1991).
Aside as weeds, rice stubbles were also present. These rice stubbles can act as
reservoir for tungro viruses and the importance of volunteer rice as a source of tungro virus
and as a temporary refuge and source of food for the vectors in harvested fields.
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
Table 3. RTV weed alternate hosts found on the fields and along irrigation canals
WEED ALTERNATE PRESENCE IN PRESENCE IN
HOST RICE FIELD IRRIGATION CANALS
Tubo-tubo South
Fimbristylis miliacea (L.)
Echinochloa sp.
Sabang
Leersia hexandra Sw.
Fimbristylis miliacea (L.)
Echinochloa sp.
Eleusine indica
Leersia hexandra Sw.
Biay
Echinochloa sp.
Leersia hexandra Sw.
Naulo
Eleusine indica
Leersia hexandra Sw.
Bayto
Echinochloa sp.
Leersia hexandra Sw.
Eleusine indica
Lucapon North
Echinochloa sp. Leersia hexandra Sw.
Fimbristylis miliacea (L.)
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
Figure 5. Weed alternate host Eleusine indica along
irrigation canals
Figure 6. Weed alternate host Leersia hexandra Sw. in
the field with rice plant showing yellowing
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
Figure 7. Weed alternate host Fimbristylis miliacea (L.)
in the field
Figure 8. Weed alternate host Echinochloa sp. On field
with rice plant at vegetative stage
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
SUMMARY, CONCLUSION AND RECOMMENDATIONS
Summary
This study was conducted to assess the incidence and severity of RTV in Bayto,
Tubo-tubo South, Biay, Naulo, Sabang, and Lucapon North Sta. Cruz, Zambales based on
symptomatology.
Among the six barangays the presence of RTV was recorded in Sabang and Tubo-
tubo South Sta. Cruz Zambales. In spite of the absence of the insect vector, weeds which
are reported to be alternate hosts, rice stubbles and volunteer rice were present infields
infected with tungro virus.
Conclusion
The incidence and severity of RTV in Sta. Cruz, Zambales in the field during
summer are generally low. Nevertheless the data should not be overlooked noting that two
rice field, Tubo-tubo South and Sabang, showed symptoms, and that the four weed
alternate hosts, rice stubbles and volunteer rice were widespread in fields. Once the insect
vector Nephotettix virescens is available, the RTV can be transmitted from infected plants
to the healthy rice plants. It happened that the insect vector was not present during the
summer period and the early immigration is greatest during rainy season.
Recommendations
Further study should be done in the same field during rainy season when the vector
is present. In addition, a greenhouse study should be done to verify the efficiency of the
different weeds as alternate hosts, rice stubbles and volunteer rice to healthy plants.
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
LITERATURE CITED
AFUN, J. V. K., JOHNSON, D.E. and A. RUSSELL-SMITH.1999.Weeds and natural
enemy regulation of insect pests in upland rice; a case study from West Africa.
Bulletin of Entomological Research (1999), 89:391- 402 Cambridge
University Press.
ANONYMOUS, 2012. Institute of Medicine Retrieved May 20 from http://nutritiondata.
self. com
ANJANEYULU, A., DAQUIOAG, M. A., MESINA, E., HIBINO, H., LUBIGAN, R. T.
and K. MOODY. 1988. Host plant of rice tungro (RTV)-associated viruses. Intl.
Rice Res. Newsl. 13(4):30-31.
BAJET, N. B., AGUIERO, V. M., DAQUIOAG, R. D.,JONSON, G. B.,
CABUNAGAN, R. C.,MESINA,E. M., and H. HIBINO. 1986. Occurrence and
spread of rice tungro spherical virus in the Philippines. Plant Disease 70:971-973.
BOTTENBERG, S. A., BARRION, P. E., KENMORE, HLitsingerJa. 1990. Presence of
tungro vectors and their natural enemies in different rice habitats in
Malaysia. Agriculture, Ecosystems & Environment Volume 31, Issue 1, May
1990, Pp. 1-15.
CABAUATAN, P. Q., KOBAYASHI, N., IKEDA, R. and H.KOGANEZAWA.
1993. Oryza glaberrima: An indicator plant for rice tungro spherical
virus. International Journal of Pest Management, 39 (3): 273-276.
CHANCELLOR, C. B., COOK, A.G. and K.L. Heong. 1996. The within-field dynamics
of rice tungro disease relation to the abundance of its major leafhopper
vectors. Crop Protection, 15 (3): 439-449.
COOK, A. G. and T. J. PERFECT. 1989. Population dynamics of three
leafhopper vectors of rice tungro viruses, Nephotettix virescens (Distant), N.
nigropictu (Stål) and Recilia dorsalis (Motschulsky) (Hemiptera: Cicadellidae), in
farmers' fields in the Philippines. Bulletin of Entomological Research (1989),
79:437-451 Cambridge University Press.
COOTER, R. J., WINDER, D. andT.C.B.CHANCELLOR. 2000. Tethered flight activity
of Nephotettix virescens (Hemiptera: Cicadellidae) in the Philippines. Bulletin
of Entomological Research (2000), 90:49-55 Cambridge University Press.
KHAN, M. A., HIBINO, H., AGUERO, V. M. and R. D., DAQUIOAG. 1991. Rice and
weed hosts of rice-associated viruses and leafhopper vectors. Plant Dis. 75: 926-
930.
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012
MOHANTY, S. K. and R. SRIDHAR. 2006. Physiology of rice tungro virus
disease: Proline accumulation due to infection. Physiological Planetarum, Volume
56 Issue1, Pp 89 – 93.
MUKHOPADHYAY, S., CHOWDURY, A. K. and S. K., CHAKRABARTY. 1986.
Epidemiology and control of rice tungro virus disease in West Bengal. Pp. 142-
153.
PAREJAREAN, A., CHETTANACHIT, D., PUTTA, M., RATTANAKARIN, W.,
ARAYAPAN, J. and S. DISTHAPORN. 1990. Hosts of rice tungro-associated
viruses (RTVs) in Thailand. Int. Rice Res. Newsl. 15(6): 21-22
NATH, N., MATHUR, S. and I. DASGUPTA. 2002. Molecular analysis of two complete
rice tungro bacilliform virus genomic sequences from India. Archives of
Virology, Volume 147, Number 6/June, 2002 1173-1187.
SRIDHAR, R., MOHANTY, S. K. and A. ANJANEYULU. 2006. Physiology of Rice
Tungro Virus Disease: Increased Cytokinin Activity in Tungro-Infected Rice
Cultivars. Physiologia Plantarum, Volume 43 Issue 4, Pp 363 – 366.
TIONGCO, E. R., FLORES, Z. M. and P. S., TENG. 1993. Inoculum sources of Rice
Tungro Viruses. Philipp. Phytopathol.Volume. 29: 30-41.
Incidence and Severity of Rice Tungro Virus in Sta. Cruz, Zambales.|
BUGTONG, MICHAEL W. MAY 2012