Tropical pickleworms found in commonwealth

RINER, Va. — The tropical pickleworm has made it to Virginia, Dr. Tom Kuhar, a Virginia Tech entomologist, told members of the Virginia Pumpkin Growers Association here during a recent field day.
Kuhar and Sean Boyle, a PhD student working with him, said the pickleworm, also known as Diaphania nitidalis is a tropical crambid moth pest that attacks cucurbit crops including pumpkins, squash and cucumbers.
The entomologists passed around some yellow squash infected with this pest more often found in Florida.
Kuhar pointed out the tiny hole the worm makes in the squash close to the bloom.
He said several Virginia pumpkin growers suffered pickleworm damage in 2018.
He speculated that those worms and the ones discovered this year were blown northward by late summer storms and changing heat patterns.
The unusually hot season this year was a topic of discussion throughout the event.
Kuhar expressed concern that this new pest to Virginia may be damaging both commercial crops and produce in home gardens.
He is hoping to establish a program to look for the pickleworm and alert growers to its presence.
“The pickleworm loves the little yellow squash,” Kuhar said. “The community garden may be the place to check.”
The entomologists said the pest’s prolific presence in late summer.
They said the insect can complete development in 30 days.
They are able to have multiple generations each year but are not known to overwinter in Virginia
The female moth can law up to 400 eggs, they said.
These are very tiny, a trait that makes them hard to monitor.
Spotting the pickleworm moths is challenging as they are not attracted to light as are many moths, Kuhar said. There also is no commercially-available pheromone lure.
Kuhr and Boyle shared information they have compiled about insecticides in use to manage these pests.
“Cucurbit growers in the South often apply insecticides weekly during the fruiting stages until final harvest,” they said.
The cost and the side effects of this use have to be considered in management decisions.
The recommendations are available from Kuhar at tkuhar@vt.edu.