Apr 7, 2016
Pesticides under more scrutiny

When “Silent Spring” was published in 1962, it triggered “fundamental changes” in the way pests were managed, said Jerry Baron, executive director of the IR-4 Project.

Rachel Carson’s book was critical of the way pesticides – specifically DDT – were used, and the impact they had on birds. The book’s popularity stoked public fears about chemical contamination of the environment and food supply, Baron said.

During the same period, the growing number and expanding usage of pesticides started to overwhelm the regulating body of the time, USDA’s Pesticide Regulation Division. In response to these pressures, President Richard Nixon ordered the creation of EPA in 1970. By 1972, the last remaining DDT registrations were cancelled – and an orderly transition to substitute pesticides was being made, Baron said.

According to Bernie Zandstra, a professor and weed control specialist with Michigan State University, growers used to use organochlorine and organophosphate insecticides (like parathion, phosdrin, TEPP, aldrin, dieldrin, chlordane and DDT), but most have been removed from the market because some were found to be hazardous to applicators. He said applicator poisoning is no longer a common occurrence.

Baron said new laws and regulations and the way they’re interpreted have had the biggest effect on the availability of pest management products over the last 50 years. Multiple chemical classes of insecticides, fungicides and herbicides have been in “vogue” at one point or another, each with positive characteristics as well as specific problems.

The most influential laws have been the 1988 and 1996 amendments to the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), known respectively as FIFRA Lite and the Food Quality Protection Act (FQPA). FIFRA Lite passed because many believed that EPA was not proceeding with pesticide data reevaluation quickly enough. The new law required EPA to complete reevaluation of pesticides according to a specific timeline. More importantly, EPA was finally given the resources to complete the reevaluations. During the implementation of FIFRA Lite, many active  ingredients were removed from the market because the manufacturers were not willing to invest in developing new data, Baron said.

For a long time, registering pest management products on vegetables was considered a minor use, because the return on investment from such small-acreage crops could not justify development expenses. To help vegetables and other specialty crops maintain adequate access to effective pesticides, USDA established the Interregional Research Project Number 4 (IR-4). Since 1963, IR-4 has “saved” more than 600 minor uses on vegetable and fruit crops by developing new residue data, Baron said.

According to Doug Doohan, a professor and herbicide specialist with Ohio State University, IR-4 and cooperating land-grant universities and companies have become extremely effective at registering new uses for weed control. But at the same time, the development of new modes of action and new active ingredients has probably never been slower.

From the February 1975 issue of Vegetable Growers News: F.E. Myers & Bro. introduced a new air boom sprayer designed for bed crops, called the A32TM Downdraft.
From the February 1975 issue of Vegetable Growers News: F.E. Myers & Bro. introduced a new air boom sprayer designed for bed crops, called the A32TM Downdraft.

“We have two trends moving in opposite directions,” Doohan said. “Probably not a good thing for herbicidal weed control.”

FQPA placed more emphasis on the use of science in risk assessments. The practical outcome was to significantly increase the cost of the data required for new registrations. It costs more than $250 million for a company to register a new pesticide today. There are more studies required for registering a pesticide than for getting a pharmaceutical approved, Baron said.

Certain older chemicals have been removed from the market since FQPA was enacted, because the risk from their use was unacceptable under the new standards. Some non-governmental organizations (NGOs), however, were not satisfied with the outcomes of new risk assessments and sued EPA. For the first time, courts became deeply involved in pesticide registration, according to Baron.

Another law affecting pesticides is the Endangered Species Act (ESA), enacted in 1973. ESA requires EPA to consult with U.S. Fish and Wildlife Service/ National Marine Fisheries Service when a potential pesticide registration might impact an endangered species. Environmental advocacy groups and NGOs have challenged EPA’s compliance to ESA by filing lawsuits. Many of the lawsuits are ongoing, and are expected to have a profound impact on the future registration of many important pesticides, Baron said.

“It seems that there is a lawsuit filed with almost every new product, claiming EPA did not follow its own provisions,” Baron said.

Public acceptance of pesticides, biopesticides and other plant protection technology is playing a larger role in which products are used to manage pests on vegetable crops. The demand for organic vegetables continues to grow, though much of the public is unaware that pesticide use is allowed in organic production, Baron said.

Consumers today are asking questions about what is in their food, and are avoiding certain products. For example, a few food processors are not allowing imidacloprid to be used on crops, even though it is legal and data has not shown it to be an excessive risk to human health. It is anticipated that these secondary standards will be used to market products in the future, Baron said.

“Retailers will state that their vegetables are better than their competition because of the products used in production,” Baron said. “This is playing on fear and implying that there is something too risky with legal pesticide use.”

Biopesticides are rapidly progressing to be part of mainstream conventional vegetable production. IR-4 advocates the use of biopesticides, along with conventional reduced-risk pesticides, in a coordinated approach, Baron said.

Zandstra mentioned other changes. He said pesticide resistance was unheard of 50 years ago (although there probably was some out there that was not recognized), but today it’s much more common. Most new fungicides are used at very low rates and are very specific to disease organisms. Application equipment has become larger and more sophisticated, but the basic principle of boom and nozzle is still widely used. And there is more organic production but weeds are still a major problem. Hand weeding works well but is costly.

Doohan said computer and camera-controlled weeding machines have lots of potential, but it seems unlikely that new technologies with the “selectivity” of herbicides are anywhere in sight. He also said the spread of glyphosate-resistant weeds is changing the environment, and will change the way vegetable and fruit producers use that important herbicide.

Matt Milkovich, managing editor


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