Development of economic injury levels for the rice leaffolder, Cnaphalocrocis medinalis (Guenee) [Lepidoptera: Pyralidae]: insect infestation and artificial leaf removal [study conducted in the Philippines]
1982
Bautista, R.C.
The widespread cultivation of IR 36 in the Philippines and its relative susceptibility to the rice leaffolder emphasized the need to quantify the insect damage on the rice variety in terms of yield and yield losses. IR 36 displayed varying degrees of sensitivity to the insect feeding when infested at two growth stages (flowering and booting). A much lower percentage of damaged leaves would cause significant yield loss at flowering compared to booting. The experiment on artificial defoliation showed that loss in yield was negatively linear with every increase in % leaf removed. The economic injury levels (EILs) determined for the two growth stages of IR 36 were based on damaged leaves and number of larvae. The EIL at flowering was specified at 4.2% damage leaves/plant
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