Monitoring and Controlling Lymantria Dispar populations Using Two Fungi, Akanthomyces Muscarius and Purpureocillium Lilacinum

Abstract

The gypsy moth Lymantria dispar (Lepidoptera: Lymantriidae), is an economically important pest of Quercus suber causing spectacular damage throughout its range. The objective of this research was to establish an effective biological control plan against L. dispar using two entomopathogenic fungi: Akanthomyces muscarius and Purpureocillium lilacinum. We identified the emergence date of 50% of the L. dispar population in Algeria, undertook biometric characterization of the six larval stages, and evaluated virulence against L. dispar larvae using three concentrations of conidia (D1=10⁶, D2=10⁵, D3=10⁴ conidia ml⁻¹). For L₂, the cumulative mortality caused by P. lilacinum reaches 100% 10 days after inoculation with the D1 concentration. For A. muscarius, maximum mortalities of 77%, 65% and 55% were observed 12 days after inoculation at concentrations D1, D2 and D3, respectively. The median lethal concentration LC₅₀ value for P. lilacinum against L₂ instar larvae (3.71x10⁴ conidia ml^-1) was significantly lower than the LC₅₀ value against L₃ instar larvae (4.26x10⁵ conidia ml^-1).