Abstract

GIUGGIA, Jorge Antonio et al. Control efficiency on "defoliating caterpillars" in soybean (Glycine max L.), with neurotoxic insecticides and insect growth regulators. Rev. Fac. Cienc. Agrar., Univ. Nac. Cuyo [online]. 2011, vol.43, n.1, pp.143-153. ISSN 1853-8665.

"Defoliating caterpillars" affect yields of soybean crops, especially in dry years of high temperatures which promote their development. The aim of this study was to assess the control efficiency of neurotoxic insecticides and IGRs on defoliating caterpillars in soybeans. Field experiments were carried out in commercial plots in three locations in the province of Cordoba in crop years 2008/09 and 2009/10 under a randomized block design with six treatments and three replications. The treatments were: T1: Chlorpyrifos (384 g p.a.ha^-1), T2: Cypermethrin (37.5 g p.a.ha^-1) T3: Lufenuron+Profenofos (15+150 g p.a.ha^-1), T4: Methoxyfenozide (28.8 g p.a.ha ^-1), T5: Novaluron (10 g p.a .ha^-1) and T6: untreated. Plot size was twelve10-m long rows spaced 0.52 m apart. The application was made with a backpack sprayer equipped with hollow cone nozzles (40 drops.cm²) when the pest reached the economic damage threshold. In each plot, five samples were taken 0, 2, 7 and 14 days after application (DAA) using the vertical cloth, identifying and quantifying live caterpillars larger than 1.5 cm. Thirty leaflets were taken per plot (middle and upper strata of the plant) 14 DAA, and defoliation percentage was determined using WinFolia Reg 2004 software. Yields were estimated on five 1-m² samples in each plot, and ANOVA and Fisher's LSD mean comparisons were conducted. Chlorpyrifos had the highest knock down effect and Methoxyfenozide the greatest efficiency 7 DAA. Overall, IGRs showed greater residual activity.

Keywords : Neurotoxic insecticides; IGRs; Defoliating caterpillars; Soybean.

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