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February 2, 2001
IPM cuts vegetable
production costs
By Lana Robinson
Field Editor
Integrated Pest Management (IPM), or the system of integrating pesticide use and cultural practices into a pest control system, has its limitations when it comes to vegetables. Still, there are environmentally friendly measures that can help reduce costs and increase the effectiveness of the dwindling arsenal of pest control chemicals.
Dr. Frank Dainello, professor and Extension horticulturist, urged vegetable farmers at Comanche County's annual vegetable shortcourse last month, "Learn to use the few chemicals we have left for maximum control. Don't spray if it isn't needed. You can increase your profit that way, and the bottom line is profitability."
Dainello noted the challenges growers of high risk crops face: markets, perishability, pest, and weather.
"When you are selling vegetables, you are selling appearance. Blemishes and quality matter. One challenge with IPM, is when you have several pests at once, it is hard to treat them at the same time," he said. "Also, weather influences disease, and you can't control the weather."
Planting resistant varieties is at the top of Dainello's list of IPM practices for small farms, followed by crop rotation, scheduled planting, cultivation, sanitation, and intercropping. He also advocated the planting of trap crops, the use of protective barriers, and sticky traps to assist in the control of pests.
"Crop rotation is a major factor for reducing organism buildup in the soil. Crop rotation enhances the productivity of a field and reduces the incidence of soil borne disease. It is also an aid to weed control and to increasing soil organic matter and nutrients," he said.
Dainello also cited the advantages of cover crops—the addition of organic matter, erosion control, addition of nutrients (particularly legumes), aeration, and improved waterholding capacity.
Short-term rotation, as defined by Dainello, is for a duration of 2-3 years in a given field or plot whereas long-term rotation, he said, is 5-7 years and takes into consideration the whole farm system.
The Extension vegetable specialist said the idea is to rotate crops in a pattern according to their level of resistance to a particular soil borne disease.
"For example, onion, garlic, leek, shallot, and sweet corn have root knot nematode resistance. So you would follow onion with corn and then fumigate before planting watermelons," said Dainello.
According to Dainello, the most desirable varieties should be high yielding, disease resistant, high quality, and early maturing, to reduce inputs and sprays.
"By selecting the right variety, you reduce the need for fungicide. The thing you want to accomplish is to use the resistance and time your fungicide," he said.
Dainello said getting the crop off to a good start goes a long way towards combating other problems. He said proper seedbed preparation is critical to successful establishment.
"You want your soil to be well pulverized and free of clods and debris, and you need good soil-to-seed contact," he advised. "Avoid excessive disking. It causes compaction and restricts root growth and yield. Roto-tillers are ideal. Also, use transplants to get away from seedling disease."
Various forms of weed control discussed by Dainello included: mechanical, chemical, crop rotation, and crop competition—based on the premise that a healthy crop crowds out weeds.
Dainello said the first 35-40 days after emergence is the critical time for weed control via cultivation.
"Some temporary sterilants are methyl bromide—now until 2004—Vapam and Eptam. Again, rotation, may help where you lose chemicals," he added.
Other weed management recommendations by the Extension horticulturist were: (1) spot treating, hand hoeing or cultivating during fallow season; (2) cover crops in the off season; (3) keeping fence rows, roadways, etc., clean; (4) cleaning equipment before moving from field to field (to remove disease spores and weeds); and (5) preplant irrigation and cultivation.
