Pests of Rice in Asian Countries
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Questions and Answers

Scotinophara spp. present on rice in the Philippines are all reported as serious pests

False

Damage by S. coarctata is not serious on Palawan Island, the Philippines

False

Insecticides have been identified for the chemical control of S. coarctata on Palawan Island

True

Insecticides are affordable for most rice farmers on Palawan Island

<p>False</p> Signup and view all the answers

Chemical insecticides cause serious resurgence of the brown planthopper, Nifaparvata lugens

<p>True</p> Signup and view all the answers

Nymphs and adults of Scotinophara sp. are relatively free of predators and parasites

<p>True</p> Signup and view all the answers

True or false: In plot PNAC-T, Mam had significantly lower numbers compared to Pl and Ma at the 9-week interval.

<p>False</p> Signup and view all the answers

True or false: In plot MAB-S, treatment Bb did not differ from the control at the 9-week interval.

<p>False</p> Signup and view all the answers

True or false: In plot MAB-T, there were no significant differences among the fungal treatments at the 9-week interval.

<p>False</p> Signup and view all the answers

True or false: In plot PNAC-S, the PI, Ma, and Mam treatments had significantly higher numbers of adults compared to Bb.

<p>False</p> Signup and view all the answers

True or false: There were significant differences in numbers of adult black bugs from the plots transplanted to susceptible and those with the tolerant rice variety.

<p>False</p> Signup and view all the answers

True or false: At the 9-week interval, significantly high numbers of nymphs were present in the untreated cages compared to cages treated with fungi at the MAB-S and MAB-T sites.

<p>True</p> Signup and view all the answers

True or false: In MAB-S treatment Mam had lower numbers of nymphs compared to Ma.

<p>False</p> Signup and view all the answers

True or false: Morimoto (1957) reported that P. lilacinus was significantly more virulent toward the black bug than M. anisopliae.

<p>False</p> Signup and view all the answers

Metarhizium anisopliae and Beauveria bassiana were collected from Palawan for the biological control of the black bug (S. coarctata)

<p>True</p> Signup and view all the answers

Paecilomyces lilacinus was collected from Malaysia for the biological control of the black bug (S. coarctata)

<p>True</p> Signup and view all the answers

Biological control using fungal enemies has been proven effective against the black bug

<p>False</p> Signup and view all the answers

Eight nylon screen cages were placed on each plot, each covering twelve hills of rice

<p>False</p> Signup and view all the answers

Two different fungal materials were used: suspensions of conidia and mass-produced dry mycelium for Metarhizium anisopliae and Paecilomyces lilacinus, and suspensions of conidia for Beauveria bassiana

<p>True</p> Signup and view all the answers

Conidia were produced on specific agars and washed off with a Tween80 solution

<p>True</p> Signup and view all the answers

Study Notes

  • The text discusses the use of fungal species for biological control of the black bug (S. coarctata) using Metarhizium anisopliae, Beauveria bassiana, and Paecilomyces lilacinus.
  • Recent collections of infected S. coarctata were made on Palawan for M. anisopliae and B. bassiana, and in Malaysia for P. lilacinus.
  • Biological control using fungal enemies has potential for future use against the black bug.
  • Two experimental fields were used, one near the Palawan National Agricultural College (PNAC) and the other in the Mabini area (MAB).
  • Half of each field was planted with the black bug-tolerant breeding line IR-10781-3-2-2, and the other half with the susceptible variety IR-20.
  • Eighteen nylon screen cages were placed on each plot, each covering twelve hills of rice.
  • Forty days after transplanting, 180 adult black bugs were introduced into each cage.
  • Two different fungal materials were used: suspensions of conidia and mass-produced dry mycelium for Metarhizium anisopliae (Ma) and Paecilomyces lilacinus (Pl), and suspensions of conidia for Beauveria bassiana (Bb).
  • Conidia were produced on specific agars and washed off with a Tween80 solution.
  • Concentrations of suspensions and viability tests were conducted.
  • Mycelium was produced in airlift fermentors, stabilized, and dried before being ground into small particles and stored.
  • Conidia germinated from dried particles after incubation.
  • Two liters of suspensions and small particles were applied with a sprayer and large particles were distributed by hand.
  • Counts of live and infected adults and nymphs were made at various intervals.
  • High nymphal mortality occurred at the PNAC site due to drought, and these data were omitted from analysis.
  • Only data on live adults from both sites and nymphs from the MAB site were analyzed using analysis of variance (ANOVA).

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Description

Learn about the common pests of rice in several Asian countries, including the serious damage caused by S. coarctata in the Philippines and the challenges faced by rice farmers in controlling this pest.

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