Seleção de isolados de fungos e nematoides entomopatogênicos visando ao controle da broca da erva-mate (Hedypathes betulinus) Kluger (Coleoptera; Cerambycidae)

Abstract

Yerba mate is a typical culture of southern Brazil, Argentina and Paraguay, with socio-economic and environmental importance. Its market is expanding and is consumed in various parts of the world. Due the lack of native culture, yerba mate has become a monoculture, and as a consequence, insects have become problematic, like that causes further damage, the borer, Hedypathes betulinus. The control is based on the pruning of attacked branches and collection of insects, but there is very potential in the use of the fungus Beauveria bassiana (Bals.) Vuill. to control this insect. In order to improve biological control in the culture, this work aims to select in laboratory, isolates of fungi, being 32 isolates of B. bassiana (Bals.) Vuill and 19 isolates of Metarhizium anisopliae (Metsch.) Sorok., and also isolates of entomopathogenic nematodes of Heterorhabditidae family. The work with fungi was done in two steps, first evaluating the pathogenicity of the isolates, and subsequently the best were selected evaluating the virulence and other biological parameters (production of fungi: vegetative growth and conidial production in the middle of culture, rice and insects cadavers). It was selected three isolates of B. bassiana (UNIOESTE 4, UNIOESTE 52 e UNIOESTE 64), highlighting the B. bassiana isolate UNIOESTE 52, and one isolate of M. anisopliae (IBCB 352), this, causing the highest confirmed mortality. Due de seasonality of the borer, and problems with the nematodes creation, were made only pathogenic evaluation, whose mortality rates ranged from zero to 75%, being the isolate NEPET 11, of Heterorhabditis sp. the most efficient