Control of wheat stink bugs (Hemiptera: Pentatomidae) in southern Brazil using the fungus Metarhizium anisopliae

Abstract

Stink bugs of the species Nezara viridula and Dichelops melacanthus are considered as some of the main insect pests associated with wheat production in Brazil. The use of the entomopathogenic fungus Metarhizium anisopliae might be an alternative for the management of these insects with chemical insecticides. Thus, the aim of this study was to evaluate and ascertain the pathogenicity of different isolates of M. anisopliae on N. viridula and D. melacanthus adults under laboratory and greenhouse conditions. In the laboratory, the fungal isolates 05RA, 11RA, 08RA, and 02RA, which were collected in the field from adults of N. viridula and D. melacanthus infected with M. anisopliae, were highly pathogenic, leading to 100% mortality in adults of N. viridula and D. melacanthus at 8 days after application (DAA). However, the isolate 08RA presented higher pathogenicity in a shorter period of time for N. viridula (mean mortality time "MMT" = 2.8 days) and D. melacanthus (MMT = 4.0 days) than the remaining isolates. At the greenhouse, the isolate 08RA led to a mortality of 44.9% (N. viridula) and 35.7% (D. melacanthus) at eight DAA; however, the mortality was 100% for both species at 14 DAA, with an MMT of 8 and 10 days for N. viridula and D. melacanthus, respectively. The fungus M. anisopliae constitutes a promising alternative agent to control the growth of adult populations of N. viridula and D. melacanthus in wheat cultures.