Field monitoring: basis for integrated management of pests on snap beans
AbstractInsects, diseases, and nematodes were monitored on snap beans in four experiments. Although the insect defoliators Anticarsia gemmatalis Hubner, Urbanus proteus (L.), Trichoplusia ni (Hubner), Liriomyza sativae Blanchard, and Diabrotica balteata Le Conte were present, defoliation did not surpass the action thresholds of 20 and 10 per cent for pre-bloom and post-bloom, respectively. Insecticide costs were reduced by 48 and 83 per cent in two field tests where field monitoring was utilized in making management decisions. Maximum initial nematode densities per 100cm3 soil were 20 for Rotylenchulus reniformis Linford and Oliveira, 15 for Helicotylenchus dihystera (Cobb) Sher, and 72 for Quinisulcius acutus (Allen) Siddiqui. Chemical treatments reduced nematode numbers but bean yields were not significantly increased.