Under the best circumstances, a grower can stand in his field on a nice warm day, just after a generous morning rain, and practically hear the sound of his crops growing. Under the worst circumstances, a grower can stand in that same field and practically hear the sound of insects chewing away at his pride and his profits.
The development of pesticide-resistant insect populations act as nature’s adaptive response to synthetic pesticides. And, more and more top growers are turning to biopesticides, in conjunction with their ongoing use of traditional pesticides.
Gaining The Upper Hand
When synthetic pesticides were introduced in the 1940s, an array of highly effective chemicals cleared fields, greenhouses, and nurseries of destructive pests, and crop yields soared. However, resistant pest populations began to emerge and render once-dependable pesticides ineffective. As new pesticide products enter the market today — many with very specific pest activity — resistance management strategies are becoming an even more important part of an operation’s long-term profitability.
Between 1950 and 2000, the incidence of new cases of arthropod pesticide resistance in the U.S. fluctuated between 50 and 150 new cases per year. According to the Food and Agriculture Organization of the United Nations (FAO), at least 520 insects and mites, 150 plant diseases, and 113 weeds have now become resistant to pesticides meant to control them.
The Biopesticide Solution
Luckily, sound science is up to the challenge. Today, most growers are rotating different combinations of traditional chemicals, from different chemical classes, and saving their favorites for key times in the growing season when they are needed. Many growers also set aside refuge areas — small, untreated plots planted next to larger, treated areas — with the hope that pests susceptible to pesticides will migrate to the refuge. This ensures that the majority of the crop is unharmed by pests and that future generations of that pest will still be susceptible to traditional pesticides.
Usage statistics indicate that more of today’s top growers have adopted what is arguably the most effective solution: incorporating biopesticides — naturally occurring or similar substances, microorganisms, and biochemicals produced in nature — into their resistance management programs.
“I think that the word is getting out that biopesticides are a highly effective way to fight resistance,” says Randy Martin, Ph.D., director of product development at BioWorks Inc. of Fairport, NY.
Biopesticides, also called “biologicals” or “biorationals,” can be used effectively either alone, in rotation, or in tank-mix combination with traditional pesticides for added resistance prevention. Biopesticides typically attack pests using multiple modes of action that differ from traditional chemicals, which makes them inherently less susceptible to the occurance of resistance.
“For us, it’s all about modes of action,” Martin explains. “Synthetic pesticides typically concentrate on one site — one protein, one gene. Biopesticides typically affect several sites and include several modes of action. Even if one action were to fail, there’s another to back it up.”
While awareness about biopesticides continues to grow, they are already mainstays in areas where insect pressure is extremely high. In some regions, nearly 100% of crops, such as tomatoes, peppers, lettuce, grapes, or rice, receive at least one application of a biopesticide per season as a standard treatment.
Mike Donaldson, president of Valent Biosciences Corporation, says more growers are beginning to understand the value that biopesticides provide in a total pest control program. Biopesticides work to extend the useful life of all products used to control damaging pests and are not intended to replace traditional chemicals.
“Growers are finding that by using combinations of biorational and traditional products to control pests, they are not only increasing the productivity of their crops, but doing it at an overall reduced cost in the long run,” he says.