Evaluation of plant extracts in the control of Oligonychus ilicis (McGregor, 1917) (Acari: Tetranychidae) on coffee tree

Abstract

Oligonychus ilicis (McGregor, 1917) (Acari: Tetranychidae) was already referred to as the second pest in importance to the coffee tree Conillon, regarded as more sensitive to the mite than Arabic. The application of synthetic pesticides in its control may provoke negative impacts to both environment and man. Alternatively to the use of such chemicals, others less impacting have appeared as for example, plant extracts. The present work was intended to evaluate the effect of plant extracts collected in the southern region of Minas Gerais on the mortality of the mite O. ilicis. The experiments were carried out on coffee tree leaves detached of plants. 79 extracts with four replicates of ten adult females were tested. The application of the chemicals in every test was done in Potter tower. With the most promising plant extracts, selected in previous trials, tests of ovicidal, topic, residual and different concentration effects were performed. The extracts of Annona squamosa L; Calendula officinalis L; Coffea arabica L, Ricinus communis L; Ginkgo biloba L and Nepeta cataria L. caused increased mortality in the residual effect test and presented no ovicidal effect to O. olicis. The obtained results show that the extract of A. squamosa was the most toxic to O. ilicis in the different tests accomplished.