This would help growers save on insecticides and costly, uncomfortable protective gear that must be worn to apply the chemicals indoors. Like the Se NPV virus, the wasp also depends on the armyworm to further its own reproduction and survival. After mating, a female Cotesia can lay eggs in 30 armyworms a day, and once parasitized, the caterpillars are as good as dead. Within days, they become a nutritious meal for hungry wasp larvae that hatch from the eggs. After emerging from their hosts, the larvae spin a cocoon, pupate, and become adult wasps.
Armyworms sometimes evade chemical sprays by hiding beneath plants' leaves.
But they may not be so lucky when a parasite like Cotesia is released. Click here to see this issue's table of contents.