Ways Produce Growers Can Replace Multisite Chemical Fungicides With Biologicals
July 25, 2024 Multisite fungicides are valued for their ability to target many different genes inside a fungus that can attack small fruit crops. But regulators, retailers, and most important, consumers, frown on them. Growers have told Kerik Cox, Cornell University Professor of Plant Pathology, that they are especially interested in reducing their use of Captan due to injury concerns.
In 2023, he conducted a trial involving day-neutral ‘Albion’ strawberries planted 12 inches apart in double rows. As in the two previous trials he found that biopesticides also have multisite mode of action. Using this approach could help growers from getting resistance to the single-site fungicides. In addition, the residuals of multisite fungicides, unlike biologicals, can remain in the environment for a long time.
Cox says biopesticides can still harm non-targets as well, but their environmental impact is greatly reduced. Historically, that’s also made them poor performers in the eyes of many. But if you can use disease forecasting, you know exactly when they need to go on, they do their job, and then they’re gone.
Synthetic multisite fungicides are popular because they are effective, and because they work in most conditions. Growers can cut corners, they don’t need a well-designed, neatly maintained planting.
“If you have a trashy planting, you’re going to get disease, and you would need to rely on heavier fungicides. If you have a wet planting, same thing,” he says. “But if you can make it dry, biopesticides will excel, and we’re seeing that this season right now in New York. We have an incredibly wet season and you can see different plantings struggling, depending on how big and bushy they are. If you put it on in a monsoon, it’s going to get disease.”
Cox realized this first hand when he inherited apple orchards, which were farmed in the old style, meaning the trees were really big and bushy. They suffered from a common malady in the Eastern U.S., apple scab. As he began planting newer open high-density orchards, a lightbulb went off as he found they were much less likely to get apple scab.
“The trees were so small, so open, and so reduced in canopy that the air is going through and stopping them from getting apple scab without any sprays at all,” he says. “And then I was like, ‘Wait a minute.’” …
For more, continue reading the full article as part of our special report on Biological Crop Protection.
In addition, check out the previous reports in Meister’s Global Insight Series covering a range of topics from Irrigation Innovations to Agricultural Technology.
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