The researchers determine the nematode's temperature and moisture requirements, the insect hosts it colonizes and other characteristics. Lists of EPN evolutionary associations, called phylogenies, are assembled to show how the nematodes have evolved in relation to each other and how they are related in a geographic region to affect similar hosts.
"We always look at the insect and nematode interactions in the laboratory first, then go out and look at the crops and environment," Stock says. Some of her work involves comparing commercially available formulations of nematodes with custom- made applications of local nematodes.
In Arizona, Stock's team is collecting native species of EPN for pest control trials in citrus and iceberg lettuce, with funding from the Arizona Citrus Research Council and the Arizona Iceberg Lettuce Research Council. Ninety percent of the citrus orchards in the state have the parasitic citrus nematode.
"We're looking for options in pest control," Stock says. "We're using the entomopathogenic nematodes to antagonize the citrus nematode and other plant-parasitic nematodes and disrupt their life cycle and their infection into the citrus roots." This study is using commercially available nematode products along with isolates of nematodes collected from Arizona's sky island (mountain) regions. For the lettuce trials, native nematodes gathered from the soil in Yuma will be used.
"It's better to use native rather than exotic nematodes to preserve biodiversity," Stock says. It's possible that similar species of nematod
Source:University of Arizona