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Air flow speed in spray boom in chemical control of Anticarsia gemmatalis and stink bugs on soybean crop

The velvetbean caterpillar, Anticarsia gemmatalis, Hübner (Lepidoptera: Noctuidae) and stink bugs are important soybean pests in Brazil. This study aimed to evaluate the pest control on soybean crop before and after the treatment with insecticide, under different air flow speed in sprayer. The study was carried out in Botucatu, State of São Paulo, Brazil, using soybean [Glycine max (L.) Merrill], Conquista (2007/2008 season). The experimental design was in randomized blocks with 4 treatments and 5 repetitions (four air flow speed: 0, 9, 11 e 29 km h-1) and non-treated plots. The insecticide was applied with support of the spray Advanced Vortex 2000 using JA-2 hollow conic nozzle and volume rates were 200 L ha-1 for both treatments. The insecticide used in the spraying for velvetbean caterpillar was the deltamethrin at 6.5 g a.i. per hectare and for stink bugs was thiamethoxam plus lambda-cialothrin at 25.38 + 19.08 g a.i. per hectare. The evaluations before and after application were made by beat cloth methods. The actual damages by stink bugs were evaluated considering the percentage of seed damage, the germination and production. In general, the average numbers of caterpillars and stink bugs were significantly lower in the treated plots in relation to non-treated, but no difference caused by air speed was found. The air speed in spray boom caused statistical difference only when compared the treatments with non-treated plots.

Glycine max; application technology; velvetbean caterpillar; Pentatomidae


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