Last year, an unknown pest threatened more than 25,000 acres of wheat along the Eastern Shore. Bill Shockley, agriculture and natural resources Extension agent in Northampton County, contacted the appropriate specialist, who identified the pest as winter grain mite, known for its rapid dispersion. Within 24 hours, 150 key producers and agricultural suppliers in the area had received relevant educational materials about this mite and within two days, more than 1,000 acres of wheat had been treated for the pest. Because of the early remedial action on the part of Virginia Cooperative Extension agents and specialists applying integrated pest management (IPM) principles, the Eastern Shore’s wheat crop was spared a potential economic hardship.
Since at least the 1970s, Extension has offered IPM-based recommendations to reduce pest populations and bring their damage down to acceptable levels. “With IPM, we combine all possible ways to fight pests, including preventative, sanitary, and cultural measures,” says Ames Herbert, pest management Extension specialist and Virginia IPM program coordinator. “IPM may be information-intensive, but people have learned that it is the best solution both environmentally and economically.”
The IPM approach covers invasive plant species and plant diseases of all kinds and does not limit itself to row-crop agriculture. “We also have IPM programs in schools, nurseries, greenhouses, forests, homes, golf courses, and even in aquatic systems,” says Herbert, who is also a professor of entomology at the Tidewater Agricultural Research and Extension Center.
Protecting soil and water resources from excess applications of pesticides is one of two motivations for IPM.
“The early crop production method was to protect against everything,” says Jim Riddell, Extension’s state program leader for agriculture and natural resources. “Integrated pest management is about using all the tools available and considering the costs, including environmental costs.”
Extension agents often encounter situations where the answer is to avoid pesticides altogether, a clear sign that IPM principles are also environmentally friendly.
“We often have years where the best solution for soybeans and wheat is not to apply insecticides,” says Keith Balderson, an agriculture and natural resources agent in Essex County who has organized conferences and field days and distributed newsletters on IPM of soybean, wheat, corn, and other crops. “For example, we found cereal leaf beetle in wheat fields in 2007, but the infestation was below the threshold level in many of those fields.”
Last year, more than 1.7 million pounds of pesticide wastes and containers were destroyed as a result of coordinated efforts between VDACS and local county Extension agents, reducing the threat of contamination into soils and groundwater. This does not mean, however, that appropriate application of pesticides is deleterious or that a pesticide-free approach is always the best option. “I work with industry as a vital partner in IPM,” Herbert adds. “We tell farmers that when an infestation exceeds the economic threshold, pesticides are the only practical control option and a valuable tool.”
These economic thresholds indicate the importance of maintaining a profitable agricultural industry, the second motivation behind IPM.
“IPM practices must always be economically feasible,” Herbert says. “The bottom line for these farmers is that they are in business.”
Virginia farmers continue to seek IPM solutions for their crop pest problems because it makes financial sense. In 2007, Virginia soybean growers saved $650,000 from IPM-based pest protection on their farms. That same year, turfgrass owners saved about $400 per acre because of improved management of troublesome grass weeds, and peanut growers saved $1.1 million because of an updated weather-based peanut disease advisory.
The development of economic thresholds has allowed for these kinds of results and has been one of the hallmarks of IPM. “After several years of research, I developed an economic threshold for corn earworm, a worm pest that feeds on soybeans throughout the state. The Corn Earworm Calculator takes into account today’s market value and today’s estimated cost,” Herbert says.
Sam Johnson, agriculture and natural resources Extension agent in Westmoreland County, has applied IPM principles for wheat, barley, corn, and other crops such as vegetables. But because of the popularity of soybeans in his county, Johnson spent much of his time working with Herbert’s calculator for corn earworm.
“Some of the economic thresholds are dependant on a certain level of crop value,” Johnson says. “For example, a threshold might have been developed when soybean value was $6 per bushel, but now that the price of soybeans is in the $11 to $12 per bushel range, we have to consider a different threshold.”
Extension agents employ a multifaceted approach regardless of the pest. “As a part of the IPM approach, we recommend farmers use disease-resistant varieties of crops, when they are available,” Balderson says. “We also suggest changes in agricultural practices, such as when to plant a crop and how narrow the rows should be. For example, we have found that if you plant wheat too early, you encounter more aphids in your crop and have to take additional measures to protect it.”
Riddell suggests that the development of these models is the real power behind land-grant institutions. “We can use our research to develop safe, effective tools and recommendations that not only increase profits but also safeguard the environment.”