Óleos essenciais e fungos entomopatogênicos no controle de Thaumastocoris peregrinus Carpintero & Dellapé, 2006 (Hemiptera: Thaumastocoridae) a campo

Abstract

The Eucalyptus genus, native to Australia, was introduced in Brazil in the 20th century and, together with production incentives, it has become one of the most produced crops of planted forest. The increase in insect pests infesting and causing damage to this crop has also increased, generating economic impacts. Among these, the tan bug (Thaumastocoris peregrinus) deserves attention. This bug is a pest insect with a sucking food habit, which causes damage to eucalyptus leaves. New control methods have been studied and developed for this pest, such as biological control and control with the use of botanical insecticides. Thus, the objective of this work was to evaluate the insecticidal effect of the essential oils of Eugenia uniflora (0.75%), Pogostemon cablin (0.75%) and the entomopathogenic fungi Beauveria bassiana (1x108 conidia.mL-1) and Metarhizium anisopliae (1x108 conidia.mL-1) on T. peregrinus adults in the field. These treatments were sprayed on branches of Eucalyptus camaldulensis. Subsequently, 10 adult T. peregrinus insects were placed in contact with the branches, which were wrapped in bags made with voile-type fabric in order to prevent the insects present there from escaping, they remained in the field for seven days and were later collected, and transported to the Biological Control laboratory. Insect mortality was evaluated and stink bug feces, present on leaves, were counted. All treatments caused mortality in adults of T. peregrinus in the field, especially the essential oil of E. uniflora and the entomopathogenic fungus M. anisopliae, but essential oil of E. uniflora was the treatment that caused the highest mortality of insects, and which had the lowest number of feces found on the leaves. Since none of the treatments, with the exception of the control, were statistically different, it is considered that the treatments in which cherry and patchouli essential oil were used and those in which the fungi B. bassiana and M. anisopliae were used are forms of control with potential on T. peregrinus adults in the field.