Adaptation of the microsporidian Thelohania pristiphorae to the tent caterpillars Malacosoma disstria and Malacosoma americanum

Abstract

Thelohania pristiphorae, a microsporidian pathogen of the larch sawfly, Pristiphora crichsonii, has been successfully adapted to the tent caterpillars Malacosoma disstria and Malacosoma americanum. The development of the pathogen in M. americanum was accompanied by the development of a nuclear polyhedrosis. The microsporidian remained virulent for the original host after six passages on both Malacosoma species. A method to obtain large quantities of spores for use against either the host of origin or the two new hosts is described.