Using cultivar mixtures to improve pest control and grain crop production

• 2012 annual report
• 2013 annual report
• 2014 annual report
• 2015 annual report

Conventional field-crop growers rely heavily on pesticides, which can have deleterious effects on human and environmental health. In contrast, organic field-crop growers have few tools that they can use economically to combat pest invasions, particularly insect herbivores and pathogens, in their fields. Therefore, designing cropping strategies that are amenable to both conventional and organic production and generate crop fields that are better able to resist pest invasion, and more resilient, will improve crop productivity for a wide range of farmers. Recent ecological research and our preliminary data indicate that intraspecific genetic diversity can be quite valuable for suppressing pest populations and improving primary productivity. Unfortunately, most fields planted with modern crop varieties harbor very little genetic diversity. Our integrated research and education project will demonstrate the pest-management potential of genotypically diverse cultivar mixtures to better resist populations of plant pathogens, insect herbivores, and even weeds to improve crop productivity. Moreover, because cultivar mixtures tend to improve yield over monocultures even in absence of pests, our work will also demonstrate general improvements in crop productivity by increasing genotypic diversity. Using field experiments at two research centers and farms of three cooperating growers, we will demonstrate and quantify production benefits of planting fields containing several different varieties of wheat. At all these sites, we will compare insect, pathogen, and weed populations and yield among cultivar mixtures and the constituent monocultures. Field days and other extension programming will expose growers to this farming strategy and generate interest for farmers to try this approach for themselves. We will seek at least 30 cooperators to trial 300 acres of cultivar mixtures on their own farms to experience improved crop productivity and decreased incidence of pest problems. Conventional growers are expected to save approximately $20/acre in pesticide costs, and both conventional and organic growers will experience 5% yield increases above their typical monoculture wheat yields, improving crop productivity. Our project will introduce a cropping strategy that promises to generate more productive and pest-resistant crop fields. Increasing crop genotypic diversity in agroecosystems is a simple approach that can be adapted to conventional or organic production with cascading ecological effects that will reduce reliance on pesticides and stabilize, or even improve, yields. Importantly, our research goals squarely align with the mission of the SARE program, which is “to advance innovations that improve profitability, stewardship and quality of life by investing in ground breaking research and education.”