BOTANICAL AND BIOLOGICAL INSECTICIDES AGAINST THE LEAF LEGS BUG (Leptoglossus zonatus, DALLAS. HEMIPTERA: COREIDAE) AND THE BLACK BEE (Trigona silvestrianun, VACHALL, HIMENOPTERA: APIDAE) AND THE EFFECT ON NATURAL ENEMIES

Abstract

The leaf legs bug (Leptoglossus zonatus, Dallas) and the black bee (Trigona silvestrianun, Vachal) have brought about severe phytosanitary and economic problems for the producers of cashew nut (Anacardium occidentale, L) in the pacific northwest of Nicaragua (Leon and Chinandega). These pests have caused great and important significant yield and quality losses, in addition of that, the production costs have been increased on this crop. Taking into account the existing problematic in these zones and in order to find a solution to the problem, a study was conducted in the Chacraseca region of the department of Leon, in the period between February 2009 to May 2010, with the aim of evaluating four botanical alternatives and one biological for the handling of the leaf legs bug and the black bee. The evaluated alternatives were a combination of: Chile + garlic + soap, Onion + chrysantemo, Chili + garlic, Metarrhizium anisopliae, Chili + soap and water as control. The evaluated variables were: number of leaf legs bugs by tree and number of black bee by tree, In addition, an evaluation of yield in kg/ha through an economic analysis of partial budget was evaluated. In order to decide the best moment for products application, weekly insect samplings were realized, taking a threshold of a one bug or one black bee found by tree. The results obtained in this study, indicate that the treatment Chile + garlic + soap was the one that presented the smaller leaf legs bug and black bee population fluctuation, followed by the treatment Chili + garlic. The economic analysis based on a partial budget, determined that the treatment Chili + garlic + soap was the one that yielded best, had the smaller variable costs and the greater net benefit. The marginal return rate was found that, in the treatment Chili + soap, per each invested dollar, a gain of 40 additional cents of dollar was obtained.

DOI: http://dx.doi.org/10.5377/calera.v11i17.773

La Calera Vol.11 No.17, p.14-25