Agriculture Commons^™

Resistance Of Wild Rices, Oryza Spp., To The Brown Planthopper, Nilaparvata Lugensi (Homoptera: Delphacidae), Wu Jung-Tsung, E. A. Heinrichs, F. G. Medrano

Department of Entomology: Faculty Publications

Of 36 wild rices screened, 19 accessions were resistant or moderately resistant to three biotypes of the brown planthopper, Nilaparvata lugens (Stål), and 9 were resistant or moderately resistant to at least one biotype. Resistant accessions were nonpreferred and N. lugens caged on resistant accessions had low food ingestion rates, slow nymphal development, reduced longevity, low fecundity, and consequently low populations. Two wild rice species decreased the percent hatchability of N. lugens eggs. Some moderately resistant accessions have tolerance to N. lugens, as indicated by low plant damage ratings and plant loss and high percentage N. lugens survival and …

Integration Of Host Plant Resistance And Insecticides In The Control Of Nephotettix Virescens (Homoptera: Cicadelli-Dae), A Vector Of Rice Tungro Virus, E. A. Heinrichs, H. R. Rapusas, G. B. Aquino, F. Palis

Department of Entomology: Faculty Publications

Combined effects of levels of vector resistance and insecticide application in control of rice tungro virus (RTV) were determined in three field tests. Cultivar “IR28,” with high levels of resistance to the vector, Nephotettix virescens (Distant), had low RTV infection in all treatments including the untreated check. In moderately resistant “IR36,” RTV decreased with an increase in level of insecticide but did not decrease to a level equaling the untreated “IR28.” The N. virescens-susceptible cultivar “IR22” had extremely high levels of RTV infection at all insecticide levels. Economic analysis indicated that gross profit and net gain were highest in …

Illustrated Guide To Integrated Pest Management In Rice In Tropical Asia, W. H. Reissig, Elvis A. Heinrichs, J. A. Litsinger, K. Moody, L. Fieldler, T. W. Mew, A. T. Barrion

Entomology Papers from Other Sources

In the past, farmers in tropical Asia grew traditional rice cultivars and either relied primarily on cultural, mechanical, and physical methods of pest control or practiced no pest control. Pesticide application was limited because the yield potential of traditional varieties was too low to justify additional investments. Although pests destroyed part of each crop, severe outbreaks or epidemics were rare.

The widespread introduction of high-yielding rice cultivars in Asia in the last two decades and the associated changes in production practices have improved conditions for insects, diseases, weeds, and rodents. The higher yield potential of the new rices also made …