Category Archives: Insecticides

Heavy Thrips Infestations in Virginia and North Carolina Cotton

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Thrips have many hosts, including grasses, grains and alfalfa. Large populations often develop on these hosts and fly into cotton fields when the cotton seedlings are developing. Thrips feeding causes severe deformation and stunting of the developing cotton leaves. The Upper Southeast cotton region (Virginia and North Carolina) could be designated “Thrips Central” for the Cotton Belt. Jack Bacheler, a North Carolina Extension Entomologist, explains…

“With the exceptionally warm winter and good moisture levels, at this point it looks like thrips flights into cotton should be both large and early this year. … Our region has earned the distinction of having the highest levels of thrips and greatest potential damage to seedling cotton of anywhere in the U.S. In some tests, with the help of a microscope, we sometimes count as many as 200 to 500 thrips per 5 seedlings! That’s a “ton” of thrips, especially if seedlings are unprotected. So it’s probably not a surprise that Virginia and North Carolina have the highest ratio of surrounding host vegetation to small average cotton field size.”

“Over the past eight years, more than 85 percent of our cotton acreage has been over-sprayed [i.e. sprayed over] following a seed treatment. With the potential for thrips damage lasting up to 5 or 6 weeks after planting and seed treatments varying from about 2 to 3 weeks in their activity, a high percentage of foliar follow-up treatments for thrips is not surprising.”

Author: Jack Bacheler
Affiliation: North Carolina Extension Entomologist
Title: Heavy thrips populations anticipated.
Publication: Southeast Farm Press, April 18, 2012. Available: http://connection.ebscohost.com/c/articles/76291692/thrips-pressure-heavy-mississippi-cotton

Grape Mealybug Control in California Depends on Insecticides

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Four species of mealybug feed on grapes in California. They suck out plant content and excrete unused plant material. The result is a layer of sticky, wet honeydew on which thick, black, sooty mold grows. The strict quality standards set by the grape industry and demanded by consumers have led to a dependence on insecticides for controlling mealybug populations.

“Although more vineyards are becoming infested, populations within infested areas are declining because the judicious use of insecticides has successfully lowered mealybug populations in areas that are infested.”

“Season-long control programs for vine mealybug are typically comprised of a combination of insecticide treatments assisted by biological control. … Promoting parasites is very important because they are active late in the growing season and can reduce vine mealybug populations before the pest begins to move to the lower part of the trunk after harvest [where they are protected from insecticides].”

Authors: Chuck Ingels, David Haviland and Steve Quashnick*
Affiliation: UC Cooperative Extension and *Wilbur Ellis
Title: Vine mealybug management in wine grapes in the northern San Joaquin Valley.
Publication: CAPCA Adviser (2012) April:34-37.

Consumer Expectations for High Quality Lettuce Require Insecticide Use

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Fresh market lettuce production in the desert growing areas of Southern California and Arizona is a billion dollar industry and the region annually produces >95% of the leafy vegetables consumed in the U.S. in the fall and winter months. Consumers desire lettuce without any blemishes or insect damage. Consumer standards result in the annual use of insecticides on the lettuce crop as described by Arizona entomologists John Palumbo and Steve Castle…

“In desert vegetable production systems, growers have been delivering high-quality safe produce to the fresh market for decades, and this has been accomplished almost exclusively through the use of insecticides.”

“…western lettuce growers and consultants have reported that chemical control is the only effective IPM tactic available for the control of most major insect pests. Naturally occurring biotic control agents are simply not capable of providing the level of crop protection necessary for meeting the marketing demands for fresh produce. … Because of the short time these crops are in the field, minor feeding activity may render the product unmarketable because of high consumer standards.”

“More recently, the fresh produce industry has experienced significant growth in the value-added market, where lettuce and other leafy greens are prepared and sold as fresh-cut lettuce packs and ready-to-eat, bagged salad mixes. The growth of this industry has also resulted in higher cosmetic standards for leafy vegetable crops, often to the point where virtually no insect contaminants or feeding blemishes are tolerated.”

Authors: John C. Palumbo and Steve J. Castle
Affiliation: University of Arizona Department of Entomology
Title: IPM for fresh-market lettuce production in the desert southwest: the produce paradox
Publication: Pest Management Science (2009) 65:1311-1320.

Research Shows Importance of Insecticides for Sweet Potato

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North Carolina is the country’s largest sweet potato producing state, totaling nearly half the entire production in the U.S. Wireworms, which live in the soil and feed on sweet potato roots, are the #1 insect enemy of sweet potato growers. Mark Abney, North Carolina State University entomologist, explains what his research has determined about the value of insecticide treatments for wireworm control…

“Abney was part of the multi-state project that ran from 2004-2007 and was designed to document which insects were major pests of sweet potatoes and begin the process of developing comprehensive IPM programs to best manage these pests. … ‘So, growers who don’t treat with an insecticide for wireworm control on sweet potatoes should expect 40 percent or more of their crop to be damaged by wireworms and for 17-20 percent of the crop to be unmarketable,’ he adds.”

Author: Roy Roberson
Title: Wireworm management a must in North Carolina sweet potatoes.
Publication: Southeast Farm Press. 2012. January 11.

Inability to Control Pest Damage Limits U.S. Organic Hop Acreage

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Hops damaged by mites, aphids and mildew are of poor quality and are unacceptable for brewing beer. Only 2% of U.S. hop acres are organic because without the use of synthetic chemical insecticides and fungicides, organic hop growers are extremely vulnerable to having their crop rejected by brewers due to poor quality. This situation is described in the following recent article…

“Demand for organically grown hops from consumers via the brewing industry is on the rise; however, due to high [nitrogen] requirements and severe disease, weed, and arthropod pressures, hops are an extremely difficult crop to grow organically.”

“Disease, fungal infection, and arthropod pests that can damage hop cone quality are controlled by frequent and persistent application of pesticides in conventional hopyards, an option unavailable to organic hop growers. … Due to the direct correlation between quality and price of hops, a crop can be drastically affected by pests and diseases that alter not just the brewing quality but also the aesthetics of the crop as well. Any loss of quality can cause a crop to lose value or be damaged to the point at which it is completely unsalable.”

“The organically certified chemical controls against arthropod pests in organic crop production are limited and generally less stable and effective than their synthetic counterparts due to uncertain efficacy, potential harm to beneficial arthropods, and cost.”

Authors: Samuel F. Turner, et al.
Affiliation: Washington State University Department of Crop and Soil Sciences
Title: Challenges and opportunities for organic hop production in the United States.
Publication: Agronomy Journal. 2011. 3(6):1645-54.

Without Insecticide Sprays, California Olives are Rejected by Food Companies

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The olive fruit fly is the most significant pest of olives worldwide. The female lays her eggs within the olive and her offspring tunnel through the inside, eating as they go, to reach the surface. This ancient pest was first discovered in California in 1998; insecticide sprays have been necessary to prevent serious damage ever since. In 2011 some California olive growers cut back on their insecticide applications. Bill Krueger, a University of California Cooperative Extension farm adviser, and Cody McCoy, Northern California field manager for Bell-Carter Foods, offered their thoughts on the implications of this decision…

“In 2011 the olive fruit fly numbers were higher than they had been since 2004, Krueger said. … ‘You certainly have to think that the lack of spraying had something to do with it, too. I know one particular case where they just didn’t start spraying early enough, and what we saw there was old damage at harvest,’ he said.”

“McCoy agreed, saying he also saw high OLFF [olive fruit fly] damage in 2011. At one point, nearly three-fourths of the olives delivered to the Bell-Carter production facility showed OLFF damage, he said. The majority of the OLFF damage was concentrated in a few olive samples, McCoy said. But because of the extent of the damage, the fruit was rejected.”

Author: Kathy Coatney
Title: Table olive growers are hoping 2012 will be a better year.
Publication: Ag Alert. February 8, 2012. pp.8-9.