Growth of the Sirex-parasitc nematode Deladenus siricidicola on strains of symbiotic fungi
Isis A. L. Caetano, Ann E. Hajek
Department of Entomology, Cornell University, Ithaca, New York, United States
Address for correspondence: ial26@cornell.edu
The nematode Deladenus siricidicola Kamona, which sterilizes Sirex noctilio females, has been extensively and successfully used as a biological control agent for this woodwasp in the Southern Hemisphere. Curiously, a non-sterilizing (NS) strain of D. siricidicola is commonly found in North America and it is thought that the NS strain was introduced with S. noctilio when this woodwasp was introduced to North America. Finding an appropriate biological control agent in North America has been challenging due to the existence of native species of Sirex woodwasps that are not considered pests but are part of the decomposer community in forests. Therefore, evaluation of biological control agents requires studies of host specificity of the nematodes. For this experiment, we evaluated the NS strain of D. siricidicola, which is poorly understood and is a potential competitor of D. siricidicola Kamona. D. siricidicola has two forms: a form that parasitizes S. noctilio and a mycophagous form that feeds on the Sirex fungal symbiont Amylostereum. The goal of this study was to compare associations between the NS and Kamona nematodes and different isolates of the symbiotic fungus, mainly to evaluate the ability of the nematodes to develop and reproduce when feeding on different isolates of Amylostereum associated with Sirex in North America.
