Small-scale field evaluation of the effectiveness of predatory earwigs against corn borer, Ostrinia furnacalis (Guenee)
2002
Rejesus, B.M. | Punzalan, E.G. (Philippines Univ. Los Banos, College, Laguna (Philippines))
The Asian corn borer (ACB), Ostrinia furnacalis is one of the most destructive pest of corn from whorl to maturity. It is capable of reducing yield of GC (green corn), Asukar and Lagkitan by 30-80% and for open pollinated variety (OPV), IPB-VAR-I by 50-70%. Small-scale field experiments were conducted to determine the effectiveness of predatory earwigs in controlling corn borer as compared to other treatments. The earwigs were released (1 earwig/sq m) to OPV 2 times at 30 to 40 days after planting (DAP) while 3 to 4 times to GC at 25, 32, 39 and 46 DAP. Monitoring of the number of plant with ACB damage was done weekly before and after earwig release. Yield data were taken upon harvest and computed in ton/ha. Results showed that 20,000 earwigs are needed in controlling ACB in OPV while 30,000 to 40,000 earwigs in GC per hectare per cropping season. With the earwig releases, 7.75 and 9.50% reduce the cost of producing OPV and GC, respectively, as compared to farmer's practice of using insecticides, resulting to an increase in net income by 5% in the former and 35% in the latter varieties
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