Comparision of different application methods to biological control Hypothenemus hampei

Abstract

There are several studies that deal with the problem of infestation by Hypothenemus hampei in Coffeea arabica. However, the ways of applying products based on entomopathogenic fungi are the same as those used for chemicals. The objective of the research was to comparison different methods of application of Beauveria bassiana against H. hampei. The experiments were developed in laboratory, with blastospores and B. bassiana airborne conidia powders were carried out. Application methods based on immersion, Potter Spray Tower and walking on treated surface. Were three experiments were carried out for each method. Bioassays’design comprised seven treatments (including the control), with five repetitions (each) and 25 beetles per repetition. Suspensions were standardized at 2.4×109, 1×109, 5×108, 1×108, 5×107 and 1×107conidia.mL-1. Conidia powder presented initial concentration of 1.14×1010and it was standardized at 1.14×109; 5.7×109; 1.14×108; 5.7×107; 1.14×107 and 5.7×106 conidia.g-1. A simultaneous test was also carried out based to the three application methods; treatment comprised conidia powder concentration of 1x108 and the control. Data were subjected to analysis of variance, which was followed by Tukey test (P<0.05) and, CL50, in the SPSS 12.1 software. The mortality better rates of H. hampei exposed to B. bassiana IBCB66 were1×108(immersion), 1×109 (Potter Spray Tower) and 1×108(walking), where as mean LC50were 6.1×108, 4.1×108, 2.4×108conidia.mL-1for each method, respectively. The highest mortality rate was recorded in the walking tests on the conidian powder at a concentration of 1×108 conidia.g-1 for the three repetitions of the method and also in the simultaneous test.