By Clint Thompson
A cold January that has already featured multiple days with sub-freezing temperatures should help vegetable growers combat the ongoing whitefly infestation. At least that’s the hope shared by Ty Torrance, University of Georgia Cooperative Extension vegetable agent for Colquitt, Tift and Worth counties.
“We’re still seeing a fair amount of whiteflies, even for the cooler temperatures. They’re mostly on winter greens like kale and collards. (The cold is) definitely killing weed species which is going to help lower the amount of alternate hosts that we have,” Torrance said. “That’s one question that has come up: Is the winter taking out all of our whiteflies? So far, the answer is no. We’re not at zero.”
Pest’s Significance
Whitefly infestations are significant because of their potential impact throughout the year. They will migrate from winter vegetables to spring vegetables to agronomic crops, like cotton, to fall vegetables and back to winter vegetables. The buildup of whiteflies is concerning since they can cause feeding injury issues in vegetables and transmit multiple viruses. These include cucurbit leaf crumple virus, cucurbit yellow stunting disorder virus, cucurbit chlorotic yellow virus, squash vein yellowing virus and tomato yellow leaf curl virus.
However, colder temperatures during the winter will help kill off the alternate hosts that whiteflies feed on this time of year.
Freezing temperatures can impact the vegetables as well.
“We can get some tip burn or leaf burn depending on the crop, just from a heavy frost-freeze event but likely not devastating. It depends on the crop. If it was broccoli versus collard, we don’t want the broccoli head itself to get any type of frost burn on. But with the foliage, if it gets burnt, it’s not going to affect the harvestability,” Torrance said.
As cold as the first couple of weeks in January have been, the coldest air of the year may loom next week. According to weather.com, low temperatures in Tifton, Georgia, are forecast to drop into the high 20s, Sunday through Tuesday, with high temperatures at 38 degrees Fahrenheit on Tuesday and Wednesday.