Allozyme and restriction fragment length polymorphism analyses confirm Entomophaga maimaiga responsible for 1989 epizootics in North American gypsy moth populations.

Abstract

In 1989, populations of North American gypsy moth, Lymantria dispar, in seven contiguous northeastern states were severely reduced by a fungal pathogen. Based on morphology, development, and pathology, this organism appeared to be Entomophaga maimaiga. We have now used allozyme and restriction fragment length polymorphism analyses to confirm this identification. Previously, this mycopathogen had been reported only from gypsy moth populations in Japan. During 1989, E. maimaiga occurred only in areas that had been initially defoliated by gypsy moth >10 years ago. E. maimaiga caused 60-88% mortality in late instar larvae on research sites in central Massachusetts.

Effects of phenological synchronization on caterpillar early-instar survival under a changing climate

“…Phenology can drive these relationships in similar ways as with multicellular natural enemies, as insect immunity can vary with host plant synchrony (Martemyanov et al 2015). The study of mycorrhizae (e.g., Tao et al 2016), phylloplane flora (e.g., Leong et al 1997), midgut biota (e.g., Mason and Raffa 2014;Martemyanov et al 2016), and pathogens (e.g., Hajek et al 1990;Leong et al 1997;van Frankenhuyzen et al 2007;Gowler et al 2015) in plant-herbivore systems is suggesting potentially important roles for multitrophic interactions with these poorly understood organisms. These relationships are only beginning to be identified and their phenologies or responses to climate have yet to be examined.…”

“…In 1989, a population upsurge was checked by an accidentally introduced Asian fungal pathogen, aided by high rainfall in May and June of that year (Hajek et al 1990). Outbreaks essentially ceased until 2015 when drought conditions in May and June prevented the fungus from controlling an upsurge that expanded into high defoliation rates in 2016 (University of Massachusetts Center for Agriculture, Food and the Environment).…”

Microsporidia Biological Control Agents and Pathogens of Beneficial Insects

“…Insect pathogens are essential components of this program, including microbial insecticides derived from the bacterium Bacillus thuringiensis kurstaki (Btk) and the baculovirus Lymantria dispar nucleopolyhedrovirus (LdMNPV) which are applied by ground and aerial sprays (McManus & Cóska 2007;Solter & Hajek 2009). A fungal pathogen from Japan, Entomophaga maimaiga, has become well established since 1989, causing widespread epizootics that can control gypsy moth populations (Hajek et al 1990;Elkinton et al 1991). Microsporidia from gypsy moth populations in Europe are considered to be important natural enemies, and they have been released into the United States as classical biological control agents (Weiser & Novotny 1987;Jeffords et al 1988;Solter & Becnel 2007).…”

Emergent fungal entomopathogen does not alter density dependence in a viral competitor

“…The L. dispar nucleopolyhedrovirus (LdNPV), present in virtually every gypsy moth population in the world, was apparently introduced to North America early with gypsy moth parasitoids introduced for biological control and historically has been known to play a key role in outbreak collapse (Dwyer and Elkinton 1993) prior to the arrival of a fungal pathogen also capable of causing epizootics. In contrast, the fungal pathogen, Entomophaga maimaiga, does not have a global distribution; this host-specific pathogenic fungus is native to Japan, northeastern China, and the Russian Far East (Nielsen et al 2005), but was discovered in the northeastern USA in 1989 (Hajek et al 1990). There, Entomophaga maimaiga increased and spread, and has now been recovered throughout the range of the gypsy moth in North America, often causing extensive mortality in gypsy moth populations (Hajek 1999).…”