Preliminary investigations to possible introduction of Entomophaga maimaiga in Sardinia

Abstract: The fungus Entomophaga maimaiga Humber, Shimazu and Soper (Entomophtorales: Entomophtoraceae) is a virulent and very host specific pathogen of the gypsy moth Lymantria dispar L., capable of causing epizootics also when the defoliator is at low population density. This fungus, originally described from the Asian gypsy moth, was introduced in the last decades of the 1900’s in the USA and Bulgaria where now it is well established causing high levels of mortality of gypsy moth larvae. The possible presence of E. maimaiga was recently investigated in Sardinia, Italy. The fungus is not present in the island so we decided (after obtaining the permit from the Ministero delle Politiche Agricole Alimentari e Forestali) to start bioassays to confirm its effectiveness against Sardinian larvae of L. dispar. Two methodologies were followed: 1) gypsy moth larvae were exposed to contaminated soil containing E. maimaiga azygospores; 2) larvae were sunk for three seconds in a water suspension containing E. maimaiga azygospores. The mortality caused by the fungus during our bioassays was 4.16% in 2012 and 3% in 2013 for the first method and 4.7% for the second method used only in 2013. We are currently verifying the action of the fungus against other lepidopteran larvae in order to avoid negative effects for the environment and lay foundations for the introduction of E. maimaiga in Sardinia.