Toxicity of Organic-Coffee-Approved Products

Abstract: Organic coffee growers in Brazil often spray a wide range of organic-farming compatible products to control pests including the southern red mite, Oligonychus ilicis. However, most of these products have not yet been proven to be effective for mite control and there is no information about their side effects on natural enemies. We evaluated the lethal and sublethal effects of three organic compatible products, the biofertilizer Supermagro, a fresh bovine manure supplemented with micronutrients, bone meal, unrefined sugar, and milk to stimulate fermentation, an enriched Bordeaux mixture (Vica Cafe Plus (R)) and lime sulfur to O. ilicis and to its predatory mite lphiseiodes zuluagai. Additionally, we evaluated the efficacy of these products against O. ilicis under greenhouse conditions. Only lime sulfur showed acute lethal effects at concentrations lower than the field recommended rates (20-40 ml/l). The predatory mite I. zuluagai was more tolerant than its prey to the three products based on acute lethal concentration bioassays. The instantaneous rate of increase (r(i)) of O. ilicis when exposed to lime sulfur at field recommended rates was negative but r(i) of the predatory mite, I. zuluagai was not. The r(i) of the predatory mite was lower than that of its prey under Supermagro and Vica Cafe exposure, including at their field recommended rates (200 ml/l and 10 g/l, respectively). In a greenhouse experiment, the control efficacy against O. ilicis 14 days after spraying reached levels higher than 80% for all three products. Lime sulfur has the potential to control O. ilicis in organic coffee plantations. Although, Supermagro and Vica Cafe exhibited potential to control O. ilicis in the greenhouse, the product concentrations used were very high and may lead to selectivity problems. Therefore, spraying suitable concentrations of such products taking into account their effectiveness against O. ilicis and their selectivity to natural enemies are important for ecological pest management in organic coffee besides benefiting coffee plant nutrition. (C) 2013 Elsevier Ltd. All rights reserved.

Reference: Tuelher, E.S., et al. (2014). Toxicity of organic-coffee-approved products to the southern red mite Oligonychus ilicis and to its predator Iphiseiodes zuluagai. Crop Protection 55: 28-34. Online: