Introduction to Integrated Pest Management Part 5: Chemical methods of pest control


By JAMES TABABA

In the previous article, the biological management practices for pest control were discussed. Here, the potential risk of chemical pesticide misuse will be explained. Other chemical methods of pest control besides pesticides will be also introduced.

READ: Introduction to Integrated Pest Management Part 4: Biological methods of pest control

Chemical methods of pest control involve using synthetic chemicals to control, suppress, and kill pests. The chemicals used to control pests are collectively called pesticides. Pesticides can be further categorized depending on their target pest. Insecticides are pesticides used to control insect pests, herbicides for weeds, fungicides for fungal diseases, nematicides for nematodes, rodenticides for rodents, and molluscicides for snails.

Spraying insecticide using a knapsack sprayer (Photo by Terkph Alive/Canva)

In IPM (Integrated Pest Management), chemical pesticides will always be the last option for controlling pests because of their numerous adverse effects on the environment and health. Pesticides are used in IPM when all alternative pest control methods are already exhausted. Traditionally, farmers rely on pesticide because it is always readily available. Also, it is highly effective for wide area applications when the pest population has not yet developed a resistance to pesticides.

Reasons to minimize the use of chemical pesticides

Pesticide resistance is the ability of pests to tolerate the effect of pesticides as the result of prolonged exposure to the pesticide. When insect pests develop pesticide resistance, they will most likely survive pesticide exposure. Chemical control will now be ineffective.  As a result,  pesticides should be applied more frequently at higher doses, costing more money, polluting the environment, and posing a greater health risk. This is why it is not recommended to rely solely on pesticide use.

Proper attire when applying pesticide (Photo by Millian Markovic/Getty Images Signature)

When pesticides are applied on the farm, not only the pest is killed but also the other non-target organisms. The non-target organisms may include beneficial insects such as pollinators such as bees and other organisms that naturally help suppress pest populations such as predators, parasitoids, and competitors. Killing the non-target organisms will disrupt the ecological balance of nature, further encouraging the growth of the pest population.

The use of pesticides also poses a threat to public health and the environment. Pesticides are toxic to humans and animals. There is a possibility that pesticides may contaminate and pollute surface and groundwater. Furthermore, pesticide residues left in fruits and vegetables are becoming a concern for most consumers.

Not only the fertilizers increase in cost, but chemical pesticides are also now affected by global inflation. The increased costs of pesticides may steer farmers away from indiscriminately using pesticides to control pests. Farmers should now begin looking for alternative pest control methods.

Aside from pesticides, other chemical pest control options have a less negative impact on the environment.

 Other chemical methods of pest control

Chemical attractants. Insects can be attracted to a variety of chemicals. An example of these chemicals is pheromones. Pheromones are chemicals emitted by female insects to attract males for mating. In pest control, the pheromones are synthetically imitated and used to lure insect pests. Pheromones are usually placed in traps to capture male insects. This process disrupts the mating cycle of the insect pests, thus controlling their population. 

Oriental fruit fly causing fruit damage (Photo from Getty Images)

The most common chemical attractants are the cue lure and methyl eugenol. These chemical attractants are used to control oriental fruit flies. Fruit fly stings cause blemishes and rot in papaya, mango, citrus, eggplant, and many other fruits and vegetables.

Most chemical attractants are non-toxic. It is also very specific for the pests of interest. Making it eco-friendly chemical pest control.

Insect growth inhibitors (IGR) are insecticides that disrupt the growth and reproduction of insects. IGRs usually do not kill adult insects. However, IGRs affect the reproductive system of insects. Some insects become sterile, and the eggs never hatch. Juvenile insects will have abnormal growth and will not become adults. Using IGR will control the insect population by preventing them from reproducing. Unlike the usual toxic pesticides, the hormone used in IGR will only affect insects, not humans. 

A pheromone trap set on the tree to catch male insects (Photo by prospective56/Getty Images)

If the pest population can be only controlled using chemical pesticides, apply responsibly. Extreme caution should be observed when handling. Pesticides are toxic. Read and follow the label. Use the appropriate amount and the right timing of application. Discard the containers properly. This reminder also applies to chemical attractants and insect growth inhibitors.

Part 6 of this article will explain the use of biotechnology and regulatory policies as an essential tactic in the implementation of IPM

READ: Introduction to Integrated Pest Management, Part 6: Biotechnology and regulatory practices of pest control

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