FUNGOS ENTOMOPATOGÊNICOS NO CONTROLE DE Oebalus poecilus (Hemiptera: Pentatomidae) NA CULTURA DO ARROZ

Abstract

Rice (Oryza sativa L.) is a plant in the grass family, which includes about 20 species. This cereal is essential for global food security, with a global production of 770 million tons of paddy rice. Brazil stands out as the largest producer and consumer of rice outside Asia, with an annual production of around 11 million tons. The rice bug Oebalus poecilus (Dallas 1851) is one of the most economically relevant pests for rice crops. Also known as the panicle bug, both adults and nymphs of this species feed on spikelets and panicle branches. The plants used in the experiments were sown in 0.3 L pots with rice seeds of the indicated cultivar, and were fertilized and irrigated periodically in a greenhouse according to the needs of the crop. Adults of O. poecilus, originating from a farm maintained by the Entomology Laboratory of Embrapa Rice and Beans, were transported to the Instituto Federal Goiano, Urutaí Campus, with adequate feeding. The insects received a topical application of a suspension of entomopathogenic fungi (Beauveria bassiana, Metarhizium anisopliae and Cordyceps javanica) and Tween 80 at 0.01% v/v. In the control treatment, only Tween 80 was applied. The results showed that the entomopathogenic fungi used during the experiment in rice crops are effective against Oebalus poecilus, with all treatments being able to infect and kill some bugs. Among the treatments, the results indicate that B. bassiana consistently demonstrated greater virulence and greater mortality in a period of 6 days. Furthermore, interference in the development of insects contaminated by B. bassiana, C. javanica and M. anisopliae was also observed, which can be explained by the production and release of secondary metabolites, which probably interfere with the metabolic processes and normal development of the hosts. Products based on these entomopathogenic fungi demonstrated the ability to infect and cause the death of some bedbugs (Oebalus poecilus), but the control obtained under field conditions was insufficient. To increase efficacy, it is recommended that future studies explore higher doses and test the products in other stages of the bedbug life cycle, such as nymphs or different instars.