Crop Diversity Decreases Pest Damage and Pesticide Use

Posted: May 16, 2012

A new Penn State research project will allow growers to improve their pest control and increase grain crop production while reducing pesticide use.

The project, being supported by a Northeast SARE grant, involves planting mixed wheat cultivars to boost genetic diversity in the field. According to John Tooker, assistant professor of entomology at Penn State and project leader, genetically diverse crops tend to be more productive and resilient, but most grain fields have very little of this diversity. “We will be experimenting with several cultivar mixtures to see what will resist pathogens, insect pests, and even weeds in a way that encourages farmers to move away from high-yielding but perhaps less resilient cultivars.”

 Conventional and organic growers can lose as much as 30 percent of their potential yields to pests such as insects, weeds, and plat diseases. Conventional growers rely heavily on pesticides, which have potential human and environmental risks, and can result in pesticide resistance. Organic growers have few tools they can use economically to combat pests and must rely integrated pest management tactics such as biological and cultural controls. Tooker says using mixed cultivars should result in fewer pesticide applications and improve yield and profitability for both conventional and organic growers.

 Tooker has already witnessed promising results growing wheat and soybeans in growth chambers, greenhouses and field test plots with insect pests such as aphids. “One greenhouse experiment showed aphid populations were significantly reduced in wheat cultivar mixtures compared to monocultures,” Tooker explains. The research team also found that the cultivar mix showed plant productivity increases even when the experiment was conducted without aphids. “Certain cultivars may typically have a higher yield, but so much of that depends on growth conditions. A mix of cultivars provides some stabilization, plus growers will be able to reduced pest management costs by up to 50 percent with very little agronomic changes.”

 Tooker is anticipating approximately 30 growers will participate in the project starting this fall; several growers he has worked with in the past have already signed on. Growers may commit to as many as 10 acres to the mixed cultivar planting, while the project provides seed and support. The project will be a research model, so results may translate to a wide range of grain crops in the northeast. Tooker adds, “People in other parts of the world are already utilizing this growing method on other types of crops with great results.”

 In addition to grower plots, Tooker will be planting winter wheat on 10 acres at the Russell E. Larson Agricultural Research Farm at Rock Springs, and a smaller plot at the Southeast Ag Research and Extension Center in Landisville. Tooker will have data collection at each participating site for the three-year project. For more information on the project, contact Tooker at 814-865-7082 or

 The Northeast Sustainable Agriculture Research and Education (SARE) program recently awarded just over $2.8 million in competitive grants to farmers, researchers, agricultural service providers, and agricultural nonprofits. These grants address sustainability from many different angles--pest management, soil quality, farm management, and the status of farms in the community. For more information on Northeast SARE, go to

 The Pennsylvania IPM program is a collaboration between the Pennsylvania State University and the Pennsylvania Department of Agriculture aimed at promoting integrated pest management in both agricultural and urban settings. For more information, contact the program at 814-865-2839, or go to