Date of Award

2014

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Environmental Sciences

First Advisor

Richard A. Casagrande

Abstract

Following three years of discovery and evaluation, three larval parasitoids were imported from Europe and introduced into North America to control Lilioceris lilii (Coleoptera: Chrysomelidae), an introduced herbivore of native and cultivated lilies. The first species, Tetrastichus setifer Thomson (Hymenoptera: Eulophidae), introduced in Massachusetts in 1999, was found to be established in 2002. We made additional releases of T. setifer, introduced the parasitic wasps, Lemophagus errabundus Szepligeti (Hymenoptea: Ichneumonidae) and Diaparsis jucunda (Holmgren) (Hymenoptera: Ichneumonidae), and evaluated the establishment and distribution of the three parasitoids through 2013. Tetrastichus setifer is now established in Massachusetts, Rhode Island, New Hampshire, Maine, Connecticut, and Ontario, Canada. Lemophagus errabundus is established in Massachusetts and Rhode Island, and D. jucunda is established in Massachusetts, Rhode Island, and Maine. All three parasitoids have spread a considerable distance from release sites. The establishment of these parasitoids is associated with substantial reductions of L. lilii populations in some locations. In time it is likely that the parasitoids will spread throughout the North American range of L.lilii, but it may be useful to redistribute the parasitoids to accelerate this process. Key Words: Lilioceris lilii, Tetrastichus setifer, Lemophagus errabundus, Diaparsis jucunda, lily leaf beetle, parasitoid, biological control, establishment

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