Pesticides

What is a pest?

• Pests are living organisms that occur where they are not wanted or that cause damage to crops or humans or other animals. Examples include:– insects, – mice and other animals, – unwanted plants (weeds), – fungi, and – microorganisms such as bacteria and viruses.

What is a pesticide?

• A pesticide is any substance or mixture of substances intended for:– preventing, destroying, repelling, or mitigating any

pest.

• Though often misunderstood to refer only to insecticides, the term pesticide also applies to herbicides, fungicides, and various other substances used to control pests.

• Under United States law, a pesticide is also any substance or mixture of substances intended for use as a plant regulator, defoliant, or desiccant.

Common Types of Pesticides

• Insecticides – kills insects

• Herbicides – kills weeds

• Fungicides – kills fungus

• Nematocides – kills round-worms

• Rodenticides – kills rodents (rats)

The groups of pesticides

• Chemical Pesticides• Biopesticides

Chemical Pesticides

• Pesticides that are created from non organic or biological means

• Examples are Organophosphate Pesticides, Carbamate Pesticides, Organochlorine Insecticide, and Pyrethroid Pesticides.

Biopesticides• Biopesticides are certain types of pesticides

derived from such natural materials as animals, plants, bacteria, and certain minerals. For example, canola oil and baking soda have pesticidal applications and are considered biopesticides. At the end of 2001, there were approximately 195 registered biopesticide active ingredients and 780 products. Biopesticides fall into three major classes: – Microbial pesticides – Plant-Incorporated-Protectants (PIPs) – Biochemical pesticides

Pesticide Generations

• The first generation of pesticides were basically natural pesticides that were extracted from plants that were fighting against pests from the beginning

• The second generation of pesticides that were created chemically. A prime example is DDT, which is a potent insecticides that was known about since 1874

The risks of Pesticides

• By their nature, most pesticides create some risk of harm - Pesticides can cause harm to humans, animals, or the environment because they are designed to kill or otherwise adversely affect living organisms.

The benefits of Pesticides

• However, pesticides are useful to society - Pesticides can kill potential disease-causing organisms and control insects, weeds, and other pests. It also helps to prevent from a deterioration of vegetation

How are we exposed to pesticides?• Pesticides can be found, often in small amounts, almost

anywhere worldwide. Where you live and your lifestyle largely determines the potential for exposure to pesticides.

• People are not intentionally exposed to pesticides, except for public health reasons. Instructions on the pesticide label are designed to minimize exposure, both to workers and the general public.

• Most non-occupational exposure comes from food or home pesticide use. In addition to use in agriculture and forestry, pesticides are used in many public places, including office buildings, restaurants, schools, parks, golf courses, and along roads, railroads and power lines.

Pesticides are found everywhere

• You may think that pesticides are only used in the field however it is also commonly used within the household. For instance, when you go camping and you bring bug repellent, that is a type of pesticide. Another example is Raid, which can kill unwanted household pests.

The fight for pesticideson human health

• Many people argue that pesticides have more benefits that risks.

• They believe that pesticides can help save lives by preventing almost “7 million people from pre-mature deaths”

• They help to prevent illness from insect-transmitted diseases such as malaria, bubonic plague, typhus, and more.

The fight for pesticides on an agricultural basis

• Pesticides lower food costs and increase food supplies– This is because pests destroy about 55% of the

world’s potential food supply.

• Without the usage of pesticides, the damage from pests would rise significantly and food costs would rise significantly because of the damage that we would receive from pests.

The fight for pesticideson a business basis

• Pesticides increase profits for farmers.

• Pesticide companies estimate that for every one dollar that is spent on pesticides, there is a four dollar profit from the crops that farmers grow. This not only would increase crop yield but would also help pesticide companies profit and farmers to grow their crops in peace.

Health risks

• Over 19% of commercial lettuce from major grocery store chains contained the pesticide DDT or DDE - Approximately 75% of all produce tested positive for various pesticide residues.  Although research suggests these levels can affect humans, the EPA does not currently require chemical companies to test their chemicals for immune system damage or subtle neurological harm.

The benefits of pesticides out-weigh the health risks

• Right now companies, although are not obligated to be tested for their chemical damages to the human immune system, believe that “the reality is that pesticides, when used in the approved regulatory manner, pose no risk to either farm workers or consumers”.

• Another reason they believe that pesticides are more beneficial then detrimental is because companies are developing “safer and more effective pesticides”.

The fight against pesticides due to genetic resistance

• The opponents of pesticides believe that the biggest problem of pesticides, is that they cause genetic resistance among the pests that they control. They believe that since insects breed rapidly, they come back even stronger each time because of genetics and evolution. A prime example is the cockroach and their incredible ability to create resistance against most of the bug sprays that it is faced against, and how they have survived for so many eons.

Pesticide TreadmillsThe threat to farmer’s business

• One of the risks of using pesticides is the constant and rising costs of pesticides.

• Since pests can grow resistance to pesticides, farmers may undergo a program where they must purchase more pesticides to apply a larger dose, however they dosage, no matter how large, becomes more and more ineffective.

Pesticides hurt the environment

• One of the major problems is that “pesticides don’t stay put”

• According to the U.S. Department of Agriculture, no more than 2% of the insecticides applied to crops by aerial spraying or by ground actually reaches the target pests.

• Pesticides that miss their target pests end up in the air, surface water, groundwater, bottom sediments, food, and nontarget organisms, including humans and wildlife

Health Problems Pesticides may Pose

• Laboratory studies show that pesticides can cause health problems, such as birth defects, nerve damage, cancer, and other effects that might occur over a long period of time.  However, these effects depend on how toxic the pesticide is and how much of it is consumed

• For these reasons, the Federal Government, in cooperation with the States, carefully regulates pesticides to ensure that their use does not pose unreasonable risks to human health or the environment. In particular, the Federal pesticide program is designed to ensure that these products can be used with a reasonable certainty that they will pose no harm to infants, children, and adults.

How does the environment break down pesticides?

• In the atmosphere, most pesticides breakdown rapidly by reaction with oxygen or free radicals, catalyzed by sunlight (indirect photolysis). Some pesticides break down by directly absorbing sunlight (photolysis). Those that persist can travel long distances in the atmosphere. In water, breakdown is usually by hydrolysis, often mediated by pH. In aquatic systems, pesticide break down by microorganisms in sediments may also be important. The predominant pathway in soil is microbial degradation, although for some pesticides chemical degradation is important.

Other Solutions to pest control

• Crop rotation • Trap Crops• Intercropping • Cross breeding plants• Introduce natural enemies • Insect birth control• Hot water can “zap” pests

Crop Rotation and protection

• Crop rotation is when the type of crop planted in a field each year can be changed.

• Another method is to plant rows of hedges or trees can be planted around fields to hinder insect invasions and provide habitats for their natural enemies.

Trap Crops

• Trap crops are basically planted to lure pests away from the main crop, that is usually human food supply. For example, in Nicaraguan cotton fields several rows of cotton are planted several months ahead of the regular crop to attract boll weevils, which can then be destroyed by hand or with small doses of pesticides.

Intercropping

• Growers cal switch from vulnerable monocultures to intercropping, agroforestry, and polyculture, which use plant diversity to reduce losses to pests. The diseased or infected plants and stalks and other crop residues that harbor pests can then be removed from the crop field.

Crossbreeding• Benefits

– Plants and animals that are genetically resistant to certain pests, insects, fungi, and diseases can be developed. This would then lower the costs of pesticides and remove many fears of health risks

• Risks– However, resistant varieties usually take a long time

and lots of money to develop by conventional crossbreeding methods. More over, if the crossbreeding fails, then more research has to be done in order for success, which in the end would take more money to accomplish

Natural Predators

• Biological control using predators, parasites, and pathogens can be encouraged or imported to regulate pest populations. More than 300 biological pest control projects worldwide have been successful, especially in China and Cuba.

• Biological control has several advantages because each predator focuses on select target species and also this method is nontoxic to other species and also to humans.

Insect Birth Control

• Males of some insects pest species can be raised in the laboratory, sterilized by radiation or chemicals. And then released into an infest area to mate unsuccessfully with fertile wild females. This technique works best if the females mate only once because once they fail, they fail and the females will not search for another mate that may be fertile.

Are Some Pesticides Safer Than Others?

• Biologically-based pesticides, such as pheromones and microbial pesticides, are becoming increasingly popular and often are safer than traditional chemical pesticides. In addition, EPA is registering reduced-risk conventional pesticides in increasing numbers.

What is "Integrated Pest Management“?

• Age-old, common-sense practices are what many people associate with IPM. Today many growers no longer apply pesticides to food on a regular basis regardless of whether or not there are insects, weeds, or other pest problems. In some parts of the country, food is being marketed as IPM food.

• Some practices for preventing pest damage may include:• inspecting crops and monitoring crops for damage, and • In technical terms, Integrated Pest Management (IPM) is

the coordinated use of pest and environmental information with available pest control methods to prevent unacceptable levels of pest damage by the most economical means and with the least possible hazard to people, property, and the environment.

How can IPM help control pests

• First keep in mind that IPM is a plan that is evaluated as if the crop and its environment is an ecological system.

• Basically the overall purpose of IPM is not the eradication of pests but the reduction of crop damage to an economically tolerable level.