Patogenicidad de paecilomyces lilacinus y metarhizium anisopliae sobre termitas microcerotermes sp. (isoptera: Termitidae)

Abstract

Laboratory bioassays were performed to determine the susceptibility of the termite Microcerotermes sp. to the entomopathogenic fungus Paecilomyces lilacinus and Metarhizium anisopliae. The termites were collected from Eucalyptus plantations at the locality San Sebastian of Buenavista, Magdalena (Colombia). Termites were maintained in darkness at mean temperature, 25°C, and relative humidity, 59,5%. The bioassays consisted in putting worker termites in direct contact with 100% cotton canvas, impregnated with concentrations of the fungus at concentrations of 1×10 1, lxlO 3, 3×10 5, l×lO 7, 3×l0 8 conidia/ml. The agar-sand method was used to evaluate the effect of the fungus. Statistical analysis showed that there were no significant differences (X 2=3,32, P=0,51) between the effects caused by P. lilacinus and the control. But, there was a significant difference in the mortality of the termites with the different concentrations, 3x10s conidia/ml being the dose that caused the highest percentages of mortality (X 2=81,3, P=0,001). With M. anisopliae significant differences were observed in the mortality at the different concentrations and the control (X 2 = 320,7, P=0,001), except for l×lO3 and 3×l05 conidia/ml (Z = -0,97, P = 0,33). The conidiation of both fungi in the dead termites was higher at the concentration of 3×10B conidia/ml (P=0,001). The DL50 was 1,78×10 sconidia/ml for P. lilacinus at two days and 0,69×l0 2 conidia/ml for M. anisopliae at seven days.