Crop Loss Assessment in Rice

Quantifying the Impact of Insecticides on Food Web Structure of Rice-Arthropod Populations in a Philippine Farmer’s Irrigated Field: A Case Study

“…Deltamethrin spraying resulted in Iocal pest outbreaks and increased the likelihood of crop damage. Insect pests of tropical rice inflict crop damage by sucking sap and clogging xylem and phloem tissues, by boring into tillers and feeding on leaves and seeds, and by transmitting rice diseases such as tungro, grassy stunt, and wilted stunt viruses (Litsinger, 1991). During spraying (28-49 DT), several common enemy species that functioned as pest specialists (Micraspis sp.…”

Insect pests of rainfed wetland rice in the Philippines: population densities, yield loss, and insecticide management

“…Poston et al (1983), Pinnschmidt et al (1995)], Litsinger (1991Litsinger ( , 1993 and Boling et al (2004) found that losses in modern rices are exacerbated when more than one stress (biotic or abiotic) affects the same growth stage. Within irrigated sites such as Guimba, high losses were associated with the combination of stemborer damage and drought (Litsinger et al 2006c), while Savary et al (1994) found the combination of stemborer damage and weediness to be associated with low yields.…”

“…Partitioned-growth-stage yield loss trials The yield loss trials involved five treatments employing the insecticide check method (Litsinger 1991). Three crop stages were recognised: (1) vegetative (transplanting to panicle initiation), (2) reproductive (panicle initiation to flowering), and (3) ripening (flowering to maturity 10 days before harvest) (Yoshida 1981).…”

Rice Planthoppers

“…For instance, leaf damages by leaf folder larvae in the early crop stages with highly visible symptoms and thus high proportion of farmers spray against these leaf feeders . However, these damages inflicted on rice crops at the early stages do not translate into crop loss (Heong 1990;Litsinger 1991). Farmers tend to overestimate losses caused by insect by more than 10 folds .…”