Projects Aim to Manage Weeds in Organic Fruit, Hemp Farming

Weed control is a problem as old as agriculture itself, but two projects from a Cornell AgriTech researcher aim to cultivate new methods for zapping the pesky plants, benefiting organic apple and grape growers and hemp producers in New York state and around the country.

Lynn Sosnoskie, assistant professor in the School of Integrative Plant Science, is collaborating on a $2 million project to study electric weed control in perennial fruit crops. She is also leading a $325,000 weed management study for hemp. Both studies are multi-institution, multistate undertakings that aim to provide growers with evidence-based, location-specific recommendations to suppress weeds and maximize yields.

Both projects began in September, will run for three years and are funded by the USDA’s National Institute for Food and Agriculture.

For the apple and grape study, Sosnoskie and collaborators at Oregon State University and the University of California-Davis, will test the performance, safety and economic and environmental sustainability of electric weed control in organic production. The organic product market topped $60 billion in 2020, and the largest market segment is fresh fruit.

Due to the nature of apple, grape and other perennial fruit plantings, crop rotation and intensive soil disturbance are not viable strategies for weed control. Organic herbicides and mulches can be expensive. Those factors led Sosnoskie and her colleagues to consider a novel weed control tool: electricity. The devices they will be testing essentially electrocute weeds by sending a jolt of electricity through the plant, damaging the plant’s cells and chlorophyll.

The researchers will study whether electric weed control can suppress weeds without damaging crops or soil health. They are also partnering with an agricultural economist to study the financial viability of electric weeders, and with an external stakeholder group of organic growers, distributors and scientific advisers to share knowledge.

For the hemp study, Sosnoskie and her colleagues will be doing more fundamental and wide-ranging work to understand best weed management practices for a crop that has been legal to grow for only five years in New York state and three years nationally.

Organic Growers Versus Weeds

Sosnoskie’s team will study and develop recommendations describing how variety choice, planting timing, cultivation, cover crops, mulching and other strategies can keep weeds at bay.

“The prohibitions on hemp production meant prohibitions on hemp research,” she said. “I get a lot of questions about weed control in hemp, and we don’t have a lot of answers other than generalities. What we’re hoping to do is fill in those details.”

Formal studies on different varieties, planting times and weather impacts on weed management would be helpful for organic farmers growing hemp, who are relying on a lot of trial and error, said Dan Doglin, co-founder of Eaton Hemp and co-owner of JD Farms, the first licensed hemp grower in New York state

“We’ve kind of been our own (research and development),” said Doglin, who is also on the board of the New York Cannabis Growers and Processors Association. “Our big challenge as an organic grower is how to prevent weeds. That’s where we need more experience with growing hemp.”

Along with Cornell, collaborating institutions for the hemp study are Virginia Tech, Southern Illinois University, North Dakota State University and Clemson University.