Resistência de genótipos de milho à lagarta do cartucho Spodoptera Frugiperda (Lepidoptera: Noctuidae)

Abstract

Among the factors that contribute to reduced productivity of corn crops is the fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae) that cause damages in the plants in all phenological cycle. The objective this work was to evaluate the resistance mechanism of resistance in corn genotypes and the tritrophic interaction with egg parasitoid Trichogramma pretiosum (Hymenoptera: Trichogrammatidae). Were adopted the corn genotypes (transgenic hybrid: 30A91 PW, 20A78 HX, Impacto VIP 3, 20A55 HX, NS90 PRO2, Maximus VIP 3, BX 1293YG, RB 9004 PRO, Feroz VIP 3, LG 6036 PW e P3862 HX, conventional hybrid: AG 1051e BM 3061 and the variety: AL Bandeirante). The experimental design adopted were randomized block and completely randomized. For the interaction between corn genotypes and parasitoid the experimental eschem adopted was in sub-subdived splot design. We evaluated the antibiosis, attractiveness and no preference in the mechanism of resistance experiments and number and damage of fall armyworm and yield parameters in field experiments and interaction with the parasitoid T. pretiosum. The transgenic genotypes 20A55 HX, 30A91 PW, LG 6036 PRO, 20A78 HX e BR 9004 PRO have moderate resitance to S. frugiperda. The conventional genotypes AG 1051 and AL Bandeirante are highly susceptible to S. frugiperda and transgenic genotype BX 1293 YG is susceptible to S. frugiperda. In the field experiment the less infestation were in NS90 PRO2, 30A91 PW, Maximus VIP 3, Feroz VIP 3, Impacto VIP 3 e RB 9004 PRO showing hight degree of resistance to S. frugiperda. The hybrid Herculex P3862 obtained fall warmworm infestation and damaged plants similar to conventional hybrid BM 3061. The less ear damage was on the Impacto VIP 3 genotype. The genotype Impacto VIP 3 was the most yield. The egg parasitoid Trichogramma pretiosum is an effective alternative in the control of Spodoptera frugiperda.