Seleção de fungos entomopatogênicos associados ao óleo de nim para controle do pulgão Lipaphis erysimi (Kalt.) (Hemiptera : Aphididae) em couve

Abstract

The aphid, Lipaphis erysimi (Kalt.) (Hemiptera: Aphididae), is considered an important pest of kale in Brazil. Botanical insecticides and the fungi Metarhizium anisopliae (Metsch.) Sorok., Beauveria bassiana (Bals.) Vuill., and Lecanicillium muscarium (Petch) Zare & Gams are promising alternatives to control aphids populations. This work aimed to evaluate isolates of entomopathogenic fungi and toxicity of the neem formulation (Neemseto®) to control L. erysimi, as well the compatibility of the selected isolates and neem oil. Survey done accros kale areas from five counties of the Agreste region in Pernambuco State resulted in presence of L. erysimi in four of them. Among 20 evaluated fungi isolates, the B. bassiana CG 001 and M. anisopliae CG 30 were the most pathogenic, providing 90 and 64% mortality towards the aphid, respectively. The CL50s for B. bassiana CG 001, M. anisopliae CG 30, and L. muscarium URPE-24 were 1,6x106,3,4x106 and 2,5x105 conidia mL-1, respectively. Bioassays with the neem formulation at concentrations 0.5, 1.0, and 2.0% were done either by leaf discs dipping or spraying the aphids on the leaf discs. All treatments caused mortality higher than 60 %, however the neem spraying treatment at 2.0% provided 90% mortality. Regarding the compatibility of B. bassiana CG001, M. anisopliae CG30 isolates with the neem oil formulation at 0.125, 0.25, and 0.5%, the 0.5% treatment did not affect the B. bassiana CG 001 viability. Compatibility test conducted with theisolates CG001 of B. bassiana and CG30 of M. anisopliae with Neemseto® at concentration 0.125, 0.25 and 0.5%, showed that the highest neem concentration caused negative impact on sporulation of the isolate CG001 and on vegetative growth and viability of the isolate CG30. These results show that the isolates B. bassiana CG001, M. anisopliae CG 30, L. muscariumURPE-24, and neem oil may be used to the control of L. erysimi.