By Blake Jackson
Apple scab, caused by Venturia inaequalis, remains one of the most costly diseases for apple growers in the Northeast. Traditionally, management has relied on routine fungicide sprays, often applied weekly using broad-spectrum synthetic products such as captan and mancozeb. However, two recent peer-reviewed studies from Cornell AgriTech point to a more targeted and sustainable approach.
Published in Plant Disease by Līga Astra Kalniņa and Kerik Cox of Cornell AgriTech’s Section of Plant Pathology and Plant-Microbe Biology, the companion studies show that disease forecasting tools can reduce dependence on synthetic multi-site fungicides. They also indicate that biopesticides can effectively replace conventional products when applications are carefully timed.
“A lot of growers feel the need to spray every week,” said Cox. “But our research shows you can be more responsible with your fungicide use if you apply using disease forecasting. A forecasting model can help you save money and reduce the frequency of application.”
Regulatory pressure is increasing on captan and mancozeb due to health and environmental concerns, with restrictions already in place in Europe and Canada.
"Growers are trying to figure out how they’re going to manage diseases without these products. Captan and mancozeb have a long residual they last a while and they can weather rain, which we get a lot of in the Northeast," said Cox.
"So growers understandably rely on them. But by using disease forecasting along with well-designed biological materials and targeted single-site fungicides, we believe growers can move away from these broad-spectrum synthetics.”
Using forecasting platforms such as Cornell’s NEWA system, researchers found comparable disease control between biological and synthetic programs, particularly in modern high-density orchards.
“The bottom line is that disease levels were incredibly low when we used the forecasting-based program I’m proposing,” said Cox. “This is a big win for NEWA.”
Photo Credit: istock-rixipix
Categories: New York, Crops, Fruits and Vegetables, Education