ABSTRACT
The objective of this study was to evaluate the oviposition behavior of Helicoverpa armigera confined in different adult pair density and growth stages of soybean plants, and the resistance of soybean genotypes to H. armigera in the category nonpreference for oviposition. The oviposition behavior of H. armigera was assessed using one, two, and four adult pairs per soybean plant of the cultivar BR-16 at the growth stages: vegetative V8 (eighth unrolled trifoliate leaf), reproductive R2 (full bloom) and reproductive R5.2 (beginning seed). The nonpreference for oviposition was evaluated using eight soybean genotypes and an oviposition preference index was calculated. The number of trichomes in leaflets was quantified for being correlated to H. armigera oviposition. One adult pair and soybean plants stage at pod-set affected and showed the best results oviposition preference on soybean plants. The genotypes M8230-RR and W711-RR presented resistance characteristics, and PI-227687 was preferred for oviposition. The trichome density positively affects the female oviposition behavior.
KEYWORDS
host plant selection; Glycine max (L.); nonpreference for oviposition; plant resistance to insects
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Temperature: 25 ± 1 °C; RH: 70 ± 10%; photophase: 12 h. Columns followed by different letters in each column are significantly different by the Tukey’s test (p < 0.05). For analysis, the data were transformed into (X + 1)1/2. Number of eggs: F = 16.49**, p = < 0.0001, Eggs per female: F = 0.54 ns, p = 0.5883.
Temperature: 25 ± 1 °C; RH: 70 ± 10%; photophase: 12 h. Columns followed by different letters in each column are significantly different by Tukey’s test (p < 0.05). 1For analysis, the data were transformed into (X + 1)1/2. Free choice: F = 7.10**, p = 0,0032; no-choice: F = 0.20 ns, p = 0.8460.
SE = standard error