Abstract

The objective of this study was to evaluate resistance mechanisms in 12 corn genotypes (transgenic hybrids: 30A91 PW, 20A78 HX, Impacto VIP 3, 20A55 HX, NS90 PRO 2, Maximus VIP 3, BX 1293YG, RB 9004 PRO, Feroz VIP 3, LG 6036 PRO; conventional: AG 1051 and variety: AL Bandeitante). Attractiveness, aversion to feeding, and antibiosis were evaluated via free and no choice tests in the laboratory. Attractiveness was evaluated at 1, 5, 10, 15 and 30 min and 1, 2, 6, 12 and 24 h by counting the number of larvae that fed on each genotype. The preference for feeding was determined by quantifying the leaf area of each genotype consumed. Antibiosis was determined by assessing biological parameters of the fed caterpillars in relation to each genotype. The biological parameters evaluated were (a) Larval stage: the viability of the larval stage and weight of larvae at ten days; and (b) pupal stage: the viability and weight of pupae at 24 h of age. After emergence, the moths were fed and evaluated to assess the longevity of the adults and the total life cycle. The transgenic genotypes NS90 PRO2, Maximus VIP 3, Feroz VIP 3 and Maximus VIP 3 elicited an aversion and/or an antibiosis reaction from fall armyworm (FAW). The transgenic genotypes HX 20A55, 30A91 PW, LG 6036 PRO, 20A78 HX and BR 9004 PRO showed a moderate resistance to FAW. The conventional genotypes AG 1051 and AL Bandeirante were highly susceptible to FAW and the transgenic genotype BX 1293 YG was susceptible to FAW.

Key words: Integrated pest management, transgenic crop, plant resistance to insects, Zea mays.