Effects of Capsicum baccatum and C. frutescens against Atta cephalotes (Hymenoptera: Formicidae) and the symbiotic fungus Leucoagaricus gongylophorus

Abstract

Leaf cutter ants are considered to be a major pest in the Neotropics, due to the considerable economic losses they cause by cutting large amounts of plant material to cultivate their symbiotic fungus. Their control is mainly achieved through synthetic products with adverse consequences to the environment and human health. In search for alternatives, the ethanolic extracts of leaves of Capsicum baccatum and C. frutescens (Solanaceae), were evaluated against medium size leaf cutter ant Atta cephalotes, and its symbiotic fungus Leucoagaricus gongylophorus. The results were promising as both plant extracts exhibited a combination of insecticidal and antifungal activity when evaluated at concentrations of 0.10, 0.25, and 0.50 % w/v. Thus, C. baccatum was shown to be the most promising as an insecticidal while, C. frutescens presented a better antifungal activity at high concentrations. Since secondary metabolites present in plants are responsible for their bioactivity, preliminary phytochemical tests and gas chromatography coupled with mass spectrometry (GCMS) of both species were carried out. In qualitative metabolite analysis, major groups detected were alkaloids, terpenoids and phenols, which are the compounds cited with the highest frequency in the management of the leaf cutter ant. Some nuclei were confirmed by GCMS, such as caryophyllene and the alkaloid conhidrine detected in baccatum, and precursors of capsaicin in C. frutescens. In this way, both species are considered promising leads for a more efficient integrated management of the leaf cutter ants.