Safe Pesticides?

Natural vs. Synthetic Pesticides
Crop Duster
90% of pesticides used today are synthetic

Editor’s Note: Over the past twenty years remarkable advancements have been made in the science of “safe” pesticides. Organic, or natural pesticides have received the most acclaim and certainly have the endorsement of environmentalists. But a great deal of progress has been made towards developing safer synthetic pesticides. At the same time, it has become increasingly likely that some synthetic pesticides, such as DDT, were not poor choices, but misused and overused. Many reputable environmental groups have urged that the use of DDT be reconsidered, because its effectiveness is unrivaled and causes minimal collateral damage when properly applied.

At the same time, organic pesticides are becoming increasingly effective and affordable. They now command over 10% of the pesticide market in the United States. But would an environmentalist endorse an “organic” pesticide that is the product of genetic engineering? That is what a “plant incorporated protectant” is; this class of pesticide relies on genetic pesticidal material being added to the plant. Similarly, what environmentalist would feel comfortable knowing their natural pesticide was what is known as a “microbial pesticide,” meaning that the pesticidal material was a fungus, or a virus, or a bacteria?

As revealed in this in-depth report by EcoWorld correspondant Daniela Muhawi, in this world of ubiquitous toxins there will never be a totally safe pesticide, and both natural and synthetic pesticides have their dangers. A synthetic pesticide takes longer to degrade. When overused, misapplied, or misconceived, it can wreak havoc. But a natural pesticide is alive. It mutates, it manipulates, it may be poorly understood. There are risks and benefits in both types of pest control, natural and synthetic; both continue to evolve, and both have a future.

It is amazing what many of us eat every day.

Thiamine mononitrate, disodium phosphate, tetrasodium purophosphate, dyes and countless other synthetic ingredients are hard to avoid when grocery shopping. We usually think that salvation from these artificial ingredients lies with the fruits and vegetables that line the produce isles, however even these natural products aren’t completely untainted by man-made concoctions.

A rivalry between farmers and insects, weeds or fungi has existed since the first agriculturalists endured the frustrations associated with these ravenous and destructive pests. Farmers have been plagued by insects that make an easy meal of their crops since the beginning. Aphids, locusts, beetles and caterpillars are just a few species that can devastate crops in just a matter of weeks. Fungi are also a great nuisance and can cause just as much, if not more, damage. Pesticides are now used by practically all farmers to control a variety of pest organisms. These pesticides end up on the produce that we purchase and many people are concerned about the risks associated with their ingestion.

The use of synthetic pesticides in the US began in the 1930s. Pesticides made it possible for farms to control pests in larger fields, and as the crops grew larger, farmers became more dependant on these synthetic pesticides. A few decades ago, DDT dominated the pesticide market. This synthetic pesticide was finally banned in the U.S in 1972 because it was found to cause extensive damage to the environment. In the U.S and other developed nations, pesticides have come a long way since the days of DDT and are no longer as hazardous.

Bar Chart of Neurotoxic Pesticide Use in California
Source: California Department of Pesticide Regulation

Thanks to the development of new pesticides, the use of neurotoxic pesticides has decreased dramatically over the years. There are also alternatives to chemical pesticides, such as biological pesticides which are preferred by many environmentalists and consumers, or even no pesticide use at all.

Agra Quest Logo

Chemical pesticides currently dominate the world market and are used at a much larger scale than the alternative-organic pesticides. Pamela G. Marrone, Ph.D, chairman and founder of AgraQuest, a biotechnology company specializing in the development of safe and environmentally friendly pest management products, estimates that 26 billion dollars are spent on synthetic pesticides worldwide per year while only 300 million is spent on biological pesticides.

Obviously, chemicals that kill millions of insects in one sweep aren’t going to be good for people either. Synthetic pesticides such as organophosphate pesticides and organochlorine insecticides have been associated with everything from cancer to neurological disorders and lung irritations in humans. However, these symptoms are highly unlikely, if not impossible, to get from a healthy dose of fruits and vegetables. You are far more likely to get sick if you don’t eat the recommended 5-9 servings of fruits and vegetables per day. Pesticides have changed drastically over the years and have become much safer for both people and the environment but many consumers are still skeptical about the existence of a “safe pesticide”.

Western IPM Center Logo

Mr. Rick Melnicoe, Director of the Western Integrated Pest Management Center and the UC Statewide Pesticide Coordinator, says that he really isn’t worried about pesticides on produce. He explains that “it is important to remember that it is the dose that makes the poison and that there is virtually no illness associated with modern pesticide residue on foods. Illnesses that DO occur are caused by misuse, exposure to concentrated levels by workers, and basic stupidity such as accidentally drinking the mixture.”

It is often argued that natural pesticides are less toxic than chemical pesticides but the truth is that both natural and synthetic pesticides can be poisonous and potentially harmful in large doses. Whether or not a substance poses a health risk depends on the amount ingested. For example, aspirin is poisonous in large doses, but a great remedy for a variety of ailments if taken responsibly. Logo

Many of us don’t realize it, but we are exposed to pesticides everyday. They don’t just occur in farms., a great website describing various toxins and pest management techniques gives a startling list of common household items and foods containing pesticides that we absorb on a daily basis: “Paint, rubbing alcohol, drinking alcohol, salt, pepper, glue, chocolate, caffeine, medications, diet pills, toothpaste, sodas, disinfectants, cleansers, and soaps-ALL have toxic properties to them…”

Even items that we consider healthy, organic and completely natural, have toxic properties: “…plants and their parts-apples, almonds, oranges, celery and carrots-have toxic properties in them, if extracted, concentrated and ingested in large enough doses; these NATURAL materials would easily kill people.” Food items you would never imagine as dangerous can have some pretty frightening results when mishandled: “If you take carrot leaves, rub them on your skin and expose the area to sunlight, blisters will form,” says Marrone.

Wheat Field
A variety of pesticides such as mineral oil,
malathiaon, sulphur dimethylamine and many
others are used to control fungi and insects
on wheat, one of America’s largest crops.
(Photo: Daniela Muhawi)

It is naive to think that we can avoid the ingestion of pesticides. In fact, we absorb so many pesticides on a daily basis that they have become a part of us. Melnicoe explains that “Chlorinated Hydrocarbons [which are synthetic pesticides such as methoxychlor, endosulfan and captan] accumulate in fatty tissue because it isn’t completely filtered out of our systems. All of us have small amounts of it in our tissue, but I’m not too worried about any negative effects. Healthy humans can detoxify the body over time and the levels are rarely high enough to do any real harm.”

It is a little disconcerting that the ingestion of toxic compounds is unavoidable. Toxicants are found in our walls, foods, drinks, gardens and apparently in our bodies. There is simply no escape. However modern synthetic pesticides have come a long way since the days they were first developed. They are now less toxic, more efficient and no longer kill all the organisms that they come into contact with but rather focus on a target species. Yet even with these advancements in synthetic pesticide development, biological (or natural) pesticides are still promoted by many environmentalists and consumers. “From a human health standpoint,” says Melnicoe, “biological pesticides are far less potent over the long term.” Most biopesticides are less toxic to people than synthetic pesticides and this is a great incentive for consumers to buy organic products. Marrone explains that “it has been shown that children who eat organic food have a significantly lower level of chemical pesticides in their blood.”

Organic foods have become extraordinarily popular amongst health and environmentally conscious individuals. Many shoppers buy organic fruits and vegetables thinking that they have grown under completely natural conditions. Danielle Slaughter is a regular customer at the Davis Food Co-op, which specializes in organic products. When asked why she preferred the slightly more expensive produce sold here over the fruits and vegetables at other grocery stores she said “When I can afford to buy organic I’ll buy that over the other produce sold at other stores. Organic produce is just healthier. I like the fact that it’s grown without pesticides and by local farmers. I like this store since it gives you the option between conventionally farmed and organic products.”


Contrary to popular belief, organic foods are NOT necessarily pesticide free. According to the USDA, “Organic food is produced without using most conventional pesticides; fertilizers made with synthetic ingredients or sewage sludge; bioengineering; or ionizing radiation.” ( But pesticides are in fact used on organic foods. Pesticides are essential for farming quality products that consumers will buy! The pesticides used by organic farmers are considered natural biopesticides. Surprisingly enough, however, the USDA “makes no claims that organically produced food is safer or more nutritious than conventionally produced food.” Some biopesticides, such as the fungicide sulphur, may even be more toxic or harmful than their synthetic counterparts.

Some farmers now use biopesticides rather than their chemical pesticides to grow the organic crops that have become so popular in recent years. The Environmental Protection Agency defines a biopesticide as “certain types of pesticides derived from such natural materials as animals, plants, bacteria, and certain minerals.” They fall into three major classes.


Microbial pesticides:

These consist of microorganisms such as a fungus, virus or bacteria.

Plant-Incorporated-Protectants (PIPs):

These are pesticidal substances that plants produce from genetic material that has been added to the plant. For example, scientists can take the gene for the Bt pesticidal protein, and introduce the gene into the plant’s own genetic material. Then the plant instead of the Bt bacterium, manufactures the substance that destroys the pest. [This increases crop yields and reduces the amount of money spent on pesticides]

Biochemical Pesticides:

These are naturally occurring substances that control pests by non-toxic mechanism…These include substances, such as insect sex pheromones, that interfere with mating, as well as various scented plant extracts that attract insect pests to traps.

United States Environmental Protection Agency Logo

There is obviously a huge selection of biological pesticides to choose from and there are no less than a thousand chemical pesticides on the market. An exhaustive list of all organic and chemical pesticides can be found on the EPA website:

It is hard to determine whether a biological or chemical pesticide is the better choice when so many different varieties are available.

Marrone explains that there are many great attributes associated with organic pesticide use but that farmers are skeptical about natural pesticides. Marrone has had trouble convincing farmers of the benefits associated with organic farming saying that “farmers often refer to organic pesticides as ‘snake oil’ and they assume the biopesticide not to work.” Even though, many farmers are still skeptical of biopesticides, plant incorporated protectants (PIP’s) are becoming increasingly popular. According to the USDA, there was a 12% increase in the use of PIP’s from 2001 to 2002. This increase has nothing to do with the rising popularity of organic produce, though. Marrone says that “plant incorporated protectants are proteins genetically engineered into the plant- they are NOT allowed in organic agriculture. While the EPA categorizes them in the biopesticide division, most do not consider genetically engineered crops biopesticides.”

Ladybug in Crops
Ladybugs are natural predators
of the pesky Aphid species
(Photo: Daniela Muhawi)

There are many advantages to using biopesticides, from both an environmental and business aspect. Marrone encourages the use of biopesticides for a variety of important reasons: “Chemical residues are minimal [in biopesticides] and often non-existent. Any toxins that are present are usually from the soil where synthetic pesticides were sprayed in the past [when they had some horrendous environmental effects]. It is also easier to export products when using biological pesticides. Europe is especially very strict when it comes to importing produce that has been sprayed with synthetics. Resistance is a major concern when it comes to pesticides. When insects become resistant to a chemical, then the pesticide is rendered useless and farmers have to look elsewhere for a solution. Chemical pesticides have a single-site effect on a pest, if a pest mutates just once it can become resistant. Natural pesticides are more complex and it is much harder to develop resistance to a biopesticide.

The biodegradability of natural pesticides is another attribute that makes them so attractive. “They are safe for the environment,” continues Marrone, “they don’t pollute the air or water, and are safe to bees, ladybeetles and other beneficial insects. There is also a shorter re-entry period for fields sprayed with biopesticides: Workers can return to the field in four hours after the use of a biopesticide. Chemical biopesticides have a much longer reentry period-one to three days-during which nothing can be done in the field. The better environmental effects of organic farming are well known — no chemical pesticides to run off into the surface water or seep into the ground water and [the use of organic pesticides rather than the conventional pesticides results in] healthier soils with more microbial diversity. The downside for the farmers, however, is that fields need to sprayed more often when using biopesticides.

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Natural Insect Control Book Cover
Natural Insect Control
by Warren Schultz

One of the most popular biopesticides is composed of Bacillus thuringiensis (Bt) proteins. Bt proteins have been used in organic farms for over 50 years. Bt proteins are completely legitimate pesticides for use in organic farming since Bt is a natural bacterium found in soils. There are many different strains of Bt, each specific to different insects. For example, Bt israelensis targets mosquitoes, blackflies and midges while Bt kurstaki effects moths ( This pesticide is very effective, but timing is key since it is the larvae that are affected and not the adults. Synthetics are a little easier to use since they generally kill the pests at any stage of their lives and can therefore be applied anytime. It is important to note though, that a biological pesticide is just as effective as the conventional version if properly used.

The use of pesticides-whether biological or synthetic- is a very controversial subject. One of the largest concerns is that of pest resistance. Once pests become resistant to a pesticide, they become an even greater threat. New synthetic pesticides are constantly being developed to overcome resistant insects or fungi. “Currently there are insects resistant to every synthetic chemical insecticide used.” (

Even though resistance to biological pesticides can occur, it is less common. “In the field, the diamondback moth is the only insect found to have developed resistance against Bt [However, about 14 other insect, such as the house mosquito, Tobacco Budworm and Colorado potato beetle, have shown resistance to Bt as well.] Farmers that use Bt are required by the EPA to take steps to prevent further resistance [such as crop rotations so pests don’t have the time to become resistant].”

Marrone is very enthusiastic about the potential market for biological pesticides but there are many misconceptions out there that damper the farmers’ and often the public’s view of natural pesticides. For example, many farmers assume biopesticides to be inefficient. However tests have shown many biopesticides to work just as well as conventional pesticides.

Even though biopesticides are quite effective, a large amount needs to be applied to the crop when compared to the conventional pesticides, which may reduce the appeal of the product to farmers. Marrone says “It takes about one lb of an undiluted biological agent (Bt) to cover an acre and only 1 gram of a synthetic agent which can give you the same results. This is not to say that one mixture is more toxic than another. Biological pesticides are often made up of living microbes and the one lb may be comprised of 1 gram of the actual beneficial microbe and the rest of the mixture is just waste and other by-products caused by fermentation so in actuality both are just as potent to the pest.” It is sometimes hard to differentiate between biopesticides and the more conventional synthetics since synthetic pesticides can also be made from natural toxins found in some plants and bacteria. Marrone explains that “natural chemicals found in plants, such as Pyrethrum in chrysanthemum flowers, are often extracted and concentrated to create the synthetic pyrethrum chemical that is found in the common household insecticide, ‘Raid’ [(Of coarse, the unmodified organic version-pyrethrum-is an organic pesticide)].”

The Lygus pest will decimate cotton
but can be diverted away by planting
smaller nearby crops it prefers

Yet another alternative to pesticide use is not to use any pesticides at all.
Dr. Pete Goodell, an advisor at the University of California Statewide Integrated Pest Management Program, believes in this holistic approach to managing pests in certain crops such as cotton. He claims that “some pests can be manipulated to stay out of crops by providing them with a patchwork of a more favorable crop such as alfalfa.” Goodell has had success using this technique with cotton crops. “Alfalfa holds key pests, such as lygus [sucking insects that take the fruiting buds of off cotton], that prefer alfalfa over the neighboring cotton crop. The insects have no reason to leave the alfalfa and therefore don’t infest the cotton. Even when the alfalfa is cut and the insects are forced to migrate to the cotton fields, they leave the crop in favor of the alfalfa when it grows back. Insects can be manipulated to stay out of certain crops by simply providing them with a few strips of a buffer crop that will contain them.” Unfortunately, this technique is not effective enough for use in high quality crops such as produce which must live up to extremely high standards.

Insects aren’t always a problem. Some insect species are even a big help to the farming community. Some gardeners release beneficial insects, such as ladybeetles and parasitic wasps, to control certain pest species-usually aphids. Marrone says that “it is remarkable how effective these natural predators are in greenhouses; up to 80% of pest species can be consumed by these natural predators.” Unfortunately, species such as ladybeetles don’t stay in place in large outdoor crops and even if they did, the farmer would have to find a way to eliminate these insects before selling his produce at the market. Food quality is reduced by any insect, whether beneficial or not.

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Pesticides in Fruit and Vegetables

Pesticides In
Fruit & Vegetables
by Susan Kegley

With less than 3% of the population in the United States producing cash crops, it is not hard to imagine how much one farmer can produce. The amount of land they have dedicated to their crop often seems endless and these farmers (and the consumer) have a lot to lose if their crops become infected by a pest species. In Melincoe’s words: “being a farmer is definitely NOT an easy job. Farmers need to be aware of the condition of their crops and often have little breathing room when threatened by a pest species-especially if the farmer has opted to use biological pesticides. It is all a matter of economics. They have to find season long control and it has to be cost effective. Farmers want to use the minimal amount of a pesticide with the most beneficial effects.”

Modern pesticides are much safer than the poisons used in the past, such as DDT. They are less toxic to the human consumer, more effective against specific pests and have little environmental effects. Both synthetic and biological pesticides are toxic to the pest. “However an important difference is that most biological pesticides are NOT considered toxic to humans, mammals and beneficials insects, birds and fish,” says Marrone.

When used responsibly, pesticides allow only 3% of the population to feed the rest without any adverse effects. New biological and conventional pesticides are constantly being developed-each one more effective and less toxic than the last. As the market for biological pesticides increases, we will also see more and more farmers use these biopesticides which are ultimately better for the environment. Until then, it is likely that farmers will use a combination of approaches that include both biopesticides and synthetic chemicals.

Woman in American Food Cooperative
“nothing will keep me from this peach…”
A satisfied shopper at the Davis Food Coop
(Photo: Daniela Muhawi)

Consumers have grown to expect quality. We have become spoiled with pre-cleaned, precut and insect free produce that is readily available at any grocery store. Jarred fruits can be poured right into your pie crusts and gourmet Greek salads complete with cheese and tomatoes come in plastic cases ready to satisfy your appetite without even a second of preparation required by the hungry consumer. None of these products would exist without pesticides, preservatives or any of the other synthetic ingredients used to improve the quality of produce. We live a synthetic life.

It is impossible to revert to a pesticide free lifestyle but this isn’t necessarily bad news. The perfect pesticide still doesn’t exist, however new pesticides are continuously being created and eventually health and environmentally conscience individuals won’t have to feel guilty about eating produce farmed with the help of these mixtures. Right now there is a choice between synthetic and biological pesticides-usually combined for the best results. Each has its advantages, but both are toxic (they are used to kill pests after all) and can have negative environmental effects. Improving pesticides is a slow and cumbersome process but until the perfect pesticide exists, toxicologists and researchers in the field of agriculture advise consumers to simply eat a good balanced diet without letting the idea of pesticides ruin your appetite for fruits and vegetables. Slaughter has the right idea. When told that even organic fruits have been grown using pesticides-sometimes a mixture of both biopesticides and synthetic pesticides her response was a good one. “Really?,” she said while inspecting a peach, “there are pesticides on organics too? Oh well, nothing is going to keep me away from this peach.”

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4 Responses to “Safe Pesticides?”
  1. D Doodler says:

    Consider this:

    Many engineered plants are modified to include a Pesticide in the gene sequence, natural or artificial pesticide is not my point; my point is that a poison is in the gene sequence of the plant.

    The poison in the gene sequence of the plant acts as a poison in the gut of the insects it is designed to deter or kill. That is, it has the same net effect as a pesticide in the gut of the insect that eats the plant.

    Can one posit for debate that the gene sequence acts the same way in the gut of a human being? That is, it acts as a poison or a pesticide, probably with detrimental effects such as killing off the beneficial bacteria (thus the rise in popularity of activia and yogurt products), and may accumulate and cause gut cancers of one kind or another?

    Can one posit for debate that some humans will be more sensitive to such poisons and pesticides than others, giving rise to an entirely new and unique set of potential allergies, horrific reactions, and organ decay?

  2. jason says:

    Ok d doodler consider this. How many people will die if pesticide were banned. The next time you are in the supermarket and see a 70 year old buy some fruit think about this. That 70 year old ate fruit 40 years ago when pesticides were 100 times more toxic.

    Oh yea founder of terminix died at age 92. Dam those pesticides huh? they must have screwed him up he died at a young age.

  3. chelsea says:

    i think that they are safe coz the population is growing so we need pestisides!

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