THE EFFECT OF INSECTICIDES USED IN CORN CROPS ON THE PARASITISM CAPACITY OF TRICHOGRAMMA PRETIOSUM RILEY, 1879 (HYMENOPTERA: TRICHOGRAMMATIDAE)ABSTRACT
The side-effects of sixteen commercial formulations of insecticides registered for corn crops were assessed for Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae) under laboratory conditions (25 ± 1o C temperature, 70 ± 10% relative humidity; 14h photophase and brightness 500 lux). The adult parasitoids were submitted to fresh dry insecticide film applied on glass plates, and the capacity of parasitism of the females was evaluated. The reduction in capacity of parasitism for the respective treatments was compared with the control (distilled water) and used to classify the insecticides into four categories: 1, harmless (< 30%); 2, slightly harmful (30– 79%); 3, moderately harmful (80–99%) and 4, harmful (> 99%). The pesticides (% active ingredient in spray water) Certero (0.012) and Rimon 100 EC (0.0075) were harmless; Fastac 100 SC (0.0025) and Match EC (0.0075) were slightly harmful; Tracer (0.024) was moderately harmful; Arrivo 200 EC (0.008), Decis 25 EC (0.0025), Deltaphos EC (0.00175 deltamethrin + 0.06125 triazophos), Dipterex 500 (0.5), Folidol 600 (0.15), Hostathion 400 BR (0.1), Karate Zeon 250 CS (0.0125), Malathion 500 CE Sultox (0.0625), Sumithion 500 CE (0.375), Turbo (0.0025) and Vexter (0.24) were harmful to adults of T. pretiosum in the test of initial toxicity under laboratory conditions.
KEY WORDS Insecta; selectivity; egg parasitoids; pesticides; Zea mays