Heat and humidity in the Southeast means hemp producers face challenges this season with regards to pests and diseases.
Matthew Brecht, cannabis grower, hemp expert and plant pathologist with Marrone Bio Innovations, said scouting is essential for growers especially since not much research has been done with this relatively new crop.
“Right now (hemp) should be transitioning to flowers. You should be having some pre-flowers maybe or about to be there. This is a time when you could have anything come in the Southeast. The east coast, Southeast, specifically is hot and humid with lots of rain events or tropical depressions that come through. You have all kinds of bugs and diseases that show up because of the humidity and pressures you have,” Brecht said.
Be on the Lookout for Worms
He noted that the worst pests for hemp are worms, especially corn earworms.
“The insects will get into the newly formed colas (cluster of buds) and basically start chewing on them. They kill the flower or parts of the flower. Once they start doing that, you could lose a good percentage of your crop. Farmers want to think about scouting for these little caterpillars and looking for either the moths or the eggs and try to time some of these applications, products that are for caterpillars during that time,” Brecht said. “Because of high humidity, you also get leaf spot. You could have hemp stem rot. You could have powdery mildew and (bud rot) towards the end.”
Brect emphasized that there wasn’t great research done in hemp prior to 2019. Hemp farming is still in its early stages, especially in Alabama, Florida and Georgia. It’s still very new with not a lot of understanding of the different pests and diseases that can be of impact.
Products are also sporadic from state to state in what growers can utilize, which could mean a challenging growing season for some farmers.
“If you don’t have proper tools to control these pests and diseases, you could potentially lose a good portion of your crop,” Brecht said. “I would say growing hemp on the east coast or the Great Lakes, anywhere that has a more humid or rainy environment during the summer time is much more difficult than it is on the west coast, much more difficult.”