US Pesticide/Herbicide Policies for Conventionally Grown Fruit

By: Cathy Sherman, B.A. Sociology

A casual stroll through the average supermarket produce section in 2010 will present a colorful picture of a wide array of fruits. Such availability doesn’t come without a price. Farmers work diligently with their crops to yield the best each year in quantity and quality, battling both weeds and pests.

To increase yields, since the 1960’s it has become necessary to use herbicides and pesticides on US crops. (Imported crops are not included in this discussion.) To deal with the challenge of responsible herbicide/pesticide use, the U.S., on the state and federal levels, has developed regulations and policies, including the need for licensing and permits.

Registering Pesticides
To become registered, the Environmental Protection Agency (EPA) must first ensure that the pesticide/herbicide, when used according to label directions, assures a reasonable certainty of no harm to human health and no unreasonable risks to the environment. More than 100 different scientific studies and tests are required from the applicant. If these chemical compounds may be used on food or feed crops, the EPA also sets maximum residue levels for the amount that can remain in or on foods.While states have authority under Section 24(c) of FIFRA (the Federal Insecticide, Fungicide, and Rodenticide Act) to add uses to pesticides based on special local needs, it doesn't allow them to register new active ingredients.  Additionally, primary enforcement responsibility for pesticide use violations may be delegated to the states.

Weed Control
Hand weeding had been the weed control method used before chemical herbicides, but its labor-intensive quality made it expensive. Narrow rows made it impossible in some species, and tractor cultivation caused such problems as tree damage and soil erosion and compaction.

Annual crops and perennial crops present different needs necessitating differing approaches to weed control. In regard to perennials such as grapes, blueberries and strawberries, weed control must be accomplished around the plants, creating a greater challenge. Weeds need to be managed all year, not just during the growing season. With annuals, the fields can be cultivated mechanically without having to consider working around the plants and roots. Fallowing is also used every so often to give the soil a chance to rejuvenate.

Key Herbicides and Controversies
Though several hundred chemical herbicides are now used directly on weeds in U.S. crop production, most fruit, vegetable and specialty crops are weed-protected by a few key herbicides that kill the primary weed species without harming the crop. Of the most-used herbicides, glyphosate-based and glufosinate-based varieties (ex: Roundup) are considered, in general, low use-rate, low toxicity, and rapid-turnover herbicides. They are claimed to have minimal toxicity to mammals and create little, if any, leaching into groundwater. These herbicides are widely used with many crops, including orchards and vineyards. Though the toxicity may be minimal to mammals, lower life forms – from microorganisms to amphibians - have been harmed by these chemicals and such herbicides must be used with extreme caution.

Paraquat, another of the most widely used herbicides in the world, is applied to the fields of many crops, including fruit orchards. It’s a quick acting, contact herbicide that is rain-fast within minutes. Upon soil contact it becomes biologically inactive. However, its use has not been allowed in Europe since 2007.

The debate over Paraquat centers on its harmful effects to the worker using it. What isn’t clear is whether or not the persons affected were following specified precautions. This exemplifies the controversy surrounding many chemicals and their use. Proponents say they are safe if applied according to directions, and critics say they are just harmful regardless of application techniques. Remember that EPA licenses are partially based on these essential words: “when used according to label directions.” Since it has been documented that many farm workers fail to follow the precautions, the controversy is intensified.

BASF Treevix Kixor herbicide is the only herbicide technology in the 'pyrimidinedione' class of chemistry that will be available in the North American market. Designed for directed, post-emergence applications in bearing and non-bearing tree crops (citrus fruit, pome fruit, and nuts), it is advertised as tree-safe and non-volatile. It quickly controls broadleaf weeds by inhibiting a key step in chlorophyll biosynthesis.

Sulfur-based herbicides are at the top of the list in terms of amount used. MANA Crop Protection recently introduced Pruvin rimsulfuron herbicide for control of some of the toughest broadleaf and grass challenges to established permanent crops such as grapes, stone fruit, apples and citrus and nut trees.

GreenMatch burndown herbicide is now available in California for use in organic crops. A post-emergence, non-selective organic herbicide, it contains citrus-extract as well as other plant extracts and surfactants. It works by stripping the wax off the weeds’ leaves, causing rapid shriveling and death.

Pesticide Usage
Pesticide usage, which may vary through the years, can be affected by such factors as weather, pest problem level, economics and crop types. These variations don’t necessarily indicate new trends, however.

As with herbicides, pesticide usage includes controversy. One such continually developing controversy involves aerial spraying. Using crop-dusters enables broader areas to be covered more efficiently, but it also opens up a much greater health danger to residents of the area. It’s an issue across the world, dealt with in the UN and in individual nations. California is only one area that has banned much aerial spraying.

In 2008, sulfur was again the most highly used pesticide, both in pounds applied and acres treated. A natural fungicide favored by both conventional and organic farmers, its primary use is to control powdery mildew on grapes and processing tomatoes.

Methyl bromide is a toxic pesticide that is added to soil before planting strawberries, grapes, almonds and other crops. It’s still used even though it is classified by the EPA as a Toxicity Category 1 compound, the most deadly category, as it can cause neural damage and reproductive harm.

An integrative approach was begun in the 1950’s, using biological and chemical agents. In 1990, in response to demands for more realistic and comprehensive pesticide use data, California became the first state to require full reporting of agricultural pesticide use. Now California’s pesticide use reporting program is recognized as the most comprehensive in the world.

On January 25, 2008, California Department of Pesticide Regulation rules were implemented to limit the use of methyl bromide, until then the sixth most highly used pesticide; metam-sodium; and other fumigants injected into the pre-planted soil to kill insects, weeds and pathogens. DPR received a court order to reduce pesticide emissions by 20 percent from 1991 levels in areas exceeding national health standards for smog.

The California DPR also conducted an EPA-funded study of alternate means of pest management with stone fruits. The project’s goal was to reduce the use of five Food Quality Protection Act-targeted pesticides - phosmet, chlorpyrifos, carbaryl, methidathian and diazinon - by 20% in the Parlier area of California. These five pesticides are typically used on stone fruit to control the Oriental fruit moth and other pests. The project demonstrated how beneficial it is to transition to less harmful pesticides in lesser amounts. Economic benefits on an average of 30% were achieved with no negative effect on insect pest control. This was due to three pest management changes: the use of target-sensing sprayers, pheromone-mating disruption, and oil use in dormant seasons. The oil alone controlled low to moderate San Jose scale levels and mite eggs while protecting beneficial insects, thus lowering grower costs.

Pheromone-mating disruption introduces synthetic pheromones into crops, which prevents undesirable insects from mating with minimal environmental damage.By 1994, the USDA found that Integrative Pest Management (IPM) adoption exceeded 50% in many California crops including grapes, oranges and pears.

Washing Off Residue/Peeling Your Produce
While waiting for more organic procedures such as these to be implemented, consumers might have to be satisfied with doing what they can to wash residues off of produce.

Several studies compared the use of tap water alone against the use of commercial vegetable washes. The findings showed that there is no advantage to using the washes. Tap water combined with brushing with a vegetable brush or hands for at least 30 seconds got rid of most of the surface residues. If more cleansing is desired, a homemade wash can be made with vinegar, lemon Juice, and salt. Additionally, a small amount of chlorine bleach may be added. Another suggestion is to use a 1% solution of dish soap.

For fruits with peels, washing isn’t necessary except to remove the residue from the fruit so it doesn’t get on hands. But peelings have been found to protect the fruit inside, so bananas, papayas, mangoes, citrus fruits and pineapple, for example, are pretty much residue-free.

It is important to note that some of the pesticides used in the studies did not come off, either with the water or with the washes. In those cases, only peeling off the skin will lessen the pesticide exposure. Since the consumer is usually not aware of which pesticides are used with store-bought produce, and since only a fraction of all the possible chemicals were studied, the consumer will have to decide whether to peel or rely on washing the fruit.

Of the fruits without protective peels, the ones that are most heavily treated with pesticides include: strawberries, raspberries, pears, peaches, nectarines, imported grapes, cherries, and apples.

 

To buy organic or not, to wash or not, to peel or not to peel, are all issues to be decided by the consumer. Add to these the matter of Genetically Modified (GM) seeds, a whole discussion topic of its own, and the subject of maintaining the nutritional value of our produce becomes more complicated.

Resources:

Bratsch, Anthony, Extension Specialist Small Fruit and Vegetable Crops,
Department of Horticulture, Virginia Tech: “Weed Management in Small Fruit
Crops”, ID, 2906-1327

Gianessi, Leonard & Sankula, Sujatha: “The Value of Herbicides in Growing
Fruit, Vegetable and Specialty Crops”, National Center for Food and
Agricultural Policy, www.ncfap.org

http://www.growingproduce.com/production/cropprotection/?storyid=3163& style=1
http://www.epa.gov/pesticides/regulating/index.htm
http://www.epa.gov/region9/ag/features/stone-fruit/index.html
http://www.cdpr.ca.gov/docs/pur/purmain.htm
http://www.ct.gov/caes/cwp/view.asp?a=2815&q=376676
http://www.lhwmp.org/home/ChemToxPesticides/shopperscard.aspx