Cucurbit crop growers in the North Central Region struggle to control cucumber beetles and the bacterial wilt pathogen they spread. The bacterium kills plants, depresses yield, and drains profits. Insecticide sprays are widely used against the cucumber beetles but damage pollinators and other beneficial insects, so their sustainability is in question. Muskmelon is highly susceptible to bacterial wilt, and organic growers often avoid planting this crop because yield losses can exceed 80%. Alternative management tactics such as biochemical lures, perimeter trap cropping, delayed planting, and crop rotation have not been reliably effective. Low tunnels covered by spunbond polypropylene fabric work well until they are removed to allow pollinator access, but then muskmelon can collapse and die from mid- to late-season wilt outbreaks. We have been testing an innovative variation on the protective tunnel theme that we call mesotunnels. Mesotunnels are more than twice as tall as low tunnels and are covered by a breathable nylon-mesh fabric that remains in place all season, with bumble bee colonies inserted underneath for pollination. In small-plot trials in Iowa in 2016 and 2017, mesotunnels increased marketable yield of organic muskmelon by an average of 450% compared to low tunnels or insecticide-only treatments – without using any insecticides. This approach therefore has promise to deliver consistently high marketable yields without the risks associated with insecticide use – a change that could open up new growing and marketing opportunities for organic cucurbit growers. Our proposed project will take the essential next steps to make mesotunnels into a workable alternative for North Central Region growers. Two years of field experiments under organic management will assess living mulches for weed control and soil quality improvement, and optimize the efficiency of purchased bumble-bee colonies for pollination under commercial-size mesotunnels (Objective 2). We will compare profitability of the mesotunnel system to current management strategies and work closely with growers to understand the factors that impact their views of the new system (Objective 2). Our intensive outreach program, mixing on-farm demonstration trials and field days in Iowa and Missouri with electronic features such as webinars and an online manual for growers, will ensure that the project’s messages reach cucurbit growers throughout the NC Region (Objective 3). Our results will have application to additional cucurbit crops that are susceptible to bacterial wilt, and for conventional producers seeking to minimize reliance on insecticides.
Project objectives from proposal:
• 250 NC Region muskmelon growers become aware of the potential value of mesotunnels to suppress pest insects and bacterial wilt.
• 80 growers learn how to use mesotunnels on their cucurbit crops
• noo growers understand the economic tradeoffs of using mesotunnels for cucurbit production.
• 60 growers (including 30 organic growers) plan to try mesotunnel systems on their own farms within 2 years.
• 30 growers try mesotunnels in their muskmelon fields during the project period.