Create Multiple Stresses for Pests

A key tenet of ecologically based pest management is to create a healthy environment for the crop and one that stresses and deters pests. Knowledge of problem pests, their behaviors and life cycles is critical when determining the tactics to use. Consider the pest’s resource and habitat needs, when and how they colonize crop fields, and the beneficial organisms that attack them. Then, apply ecological strategies that will work against their preferences.

For example, disrupt a pest’s habitat by rotating to a new non-host crop. Insects and diseases that specialize in a particular crop will have a hard time without their host. Reduce weeds’ access to sunlight by using narrower crop row spacing or with cover crop residues. Experiment with wider row spacing to minimize the humid conditions that fungal and bacterial crop diseases thrive in. Disrupt the ability of insect pests to disperse across your farm by bordering crop fields with non-host plants. This strategy works by jumbling the visual and chemical cues that pest insects use to locate host crops. Mating-disruption pheromone traps can confuse mate-seeking insects and lower the pest’s ability to reproduce. Sanitizing your harvest and weeding equipment between uses can also reduce the spread of weed seeds or pathogens across your farm.

The SARE fact sheet Ecological Management of Key Arthropod Pests in Northeast Apple Orchards (sare.org/apple-pests) provides examples of these strategies in action for common orchard pests in the Northeast. Cornell University’s Resource Guide for Organic Insect and Disease Management offers examples of ecological strategies that can be used to manage common pests in the production of vegetable crops.

Project Highlight: Deterring a Pest with Cover Crops

The flatheaded appletree borer, a longtime orchard pest, has a hard time finding host trees to lay eggs in when cover crops are involved. A farmer and a team of researchers from Tennessee State University (OS14-084) overseeded winter cover crops into their maple nurseries to manage appletree borers and weeds. They found that growing a mix of crimson clover and annual rye between transplanted trees reduced borer damage by up to 95%. The cover crop created unfavorable habitat for the pest by acting as a barrier that hid host tree trunks from foraging appletree borers. Further, the cool, shaded environment provided by the cover crop reduced weeds and deterred appletree borers, which prefer to lay their eggs on warm, sunny, low-lying areas of host trees. The cover crop was as effective as the conventional approach, which used insecticides and herbicides.

Project Highlight: Physical Pest Exclusion

Plagued with the invasive spotted wing drosophila (SWD) on her farm in New York, berry producer Dale Ila Riggs recalled losing 40% of her blueberry crop and 25% of her raspberry crop to an infestation in 2012. With the help of a SARE grant (FNE14-813), she tested exclusion netting as a tactic to keep the flies off her berry crops and to keep the number of sprays down. Riggs found that exclusion netting worked very well on her operation, reducing infestation levels of SWD in covered berries to less than 1%. The next year, exclusion netting was even more effective at reducing SWD compared to uncovered, sprayed berries that received as many as five insecticide applications during harvest season. Read more about SWD management in these related publications:

• Management Recommendations for Spotted Wing Drosophila in Organic Berry Crops
• Integrated Strategies for Management of Spotted Wing Drosophila in Organic Small Fruit Production
• Spotted Wing Drosophila Pest Management Recommendations for Southeastern Blueberries

For further reading about high tunnel production, visit SARE’s High Tunnels and Other Season Extension Techniques.