On-farm Verification of Integrated Pest Management (IPM) Technologies Developed for Asian Corn Borer Against the Corn Earworm, Helicoverpa armigera (Hubner) in San Jose, Occidental Mindoro, Philippines

摘要

The effectiveness of integrated pest management (IPM) technologies developed for the Asian corn borer was modified and verified against Helicoverpa armigera in yellow corn. The experiment was conducted for two consecutive dry season plantings from December 1999 to April 2000 and December, 2000 to April 2001. The two field releases of Trichogramma chilonis Ishii in the IPM plots at the rate of 50 Trichogramma cards per hectare reduced earworm damage. The presence of natural enemies like coccinellid beetles and spiders supplemented the action of Trichogramma in reducing the damage. Single spot application of carbofuran in the IPM plots at mid-whorl stage based on temporary economic threshold level (ETL) of 40% earworm-damaged plants is not desired. In farmers' fields, insecticide applications were improperly timed. The cost of controlling corn earworm showed that the net income do not significantly differ among treatments. This suggests that corn earworm is not yet really severe enough that causes significant yield reduction.