VIRULÊNCIA DE FUNGOS ENTOMOPATOGÊNICOS NO CONTROLE DE PERCEVEJO DO COLMO DE ARROZ Tibraca limbativentris (HEMIPTERA: PENTATOMIDAE)

Abstract

Stink bugs of the family Pentatomidae (Hemiptera) are one of the main groups of sucking pests that negatively impact rice crops in Brazil. The high incidence of Tibraca limbativentris can result in severe productivity losses and, in extreme cases, lead to total crop loss. This study aimed to evaluate the efficiency of the fungi Beauveria bassiana, Metarhizium anisopliae, and Cordyceps javanica in causing mortality of eggs, nymphs, and adults of the insect at different concentrations. Laboratory bioassays were conducted using a completely randomized design (CRD). Conidial suspensions of the fungi were prepared at different concentrations. Eggs and insects were exposed to the fungi by immersion and maintained under controlled temperature (26 ± 2°C) and relative humidity (70 ± 5%) conditions. After application, mortality was assessed daily for 10 days for eggs and for 20 days for nymphs and adults. Statistical analysis was performed using generalized linear models (GLM) with a binomial distribution for mortality data and ANOVA for average comparisons. The results indicated significant differences among the tested fungi. Cordyceps javanica exhibited the highest egg mortality rate, with increasing efficiency as the concentration increased. Metarhizium anisopliae was the most effective against nymphs, reaching the highest lethality rate at a concentration of 1×10⁹ conidia/mL. For adults, B. bassiana and C. javanica showed higher biological efficacy, while M. anisopliae was less effective. The interaction between fungus and dose was statistically significant, indicating that the biological response depends on concentration and the insect's developmental stage. These findings confirm the potential of entomopathogenic fungi as a viable tool for the biological control of T. limbativentris, reducing dependence on chemical insecticides. The efficiency of the fungi varied according to dose and insect stage, highlighting the importance of adjusting application strategies to maximize control. Further research is recommended to optimize the use of these agents and assess their effectiveness under field conditions.