Eficiência de inseticidas para preservar madeira contra danos de cupim subterrâneo

Abstract

A field test was developed to evaluate the efficiency of three insecticides as wood preservatives against damages caused by the subterranean termite Coptotermes havilandi Holmgren, 1911 (Isoptera: Rhinotermitidae). The commercial products with their respective appraised active ingredients were: Dursban 4E chlorpyrifos; Diazinon 60 EC diazinon and Dragnet 384 CE permethrin. The product Diazinon 60 EC was used, in that experiment, as reference for possessing the highest factory concentration (60% p/p) than the others. The i.a were diluted in water in the concentrations of 0,5%; 1,0%; 1,5% and 2,0% and the samples, measuring 30cmx2,5cmx2,5cm made of Pinus wood sp were submitted to the treatment by immersion in the preservative solutions for five minutes. The samples without treatment (none concentration), were used as control-group. The product Diazinon 60 EC presented better result with the largest medium values for the variable retention in all of the used concentrations. They were certain the values of retention of i.a. in each sample.. The samples were put in three areas of different forest systems for expoxition to the termites. To the end of two periods, 12 and 18 months, the samples were removed for visual interpretation of the structural damages. The performance of the analyzed products was certain through the use of efficiency classes, to represent the intensity of the damages, corresponding to qualitative values of preservation of the wood. The results were interpreted by statistical comparison.. The permetrina, was the product of better acting in the preservation of the samples after the two periods studied, with medium index of preservation around 100%, differing estatisticaly of the other tested products.