Script 28.3

Notes to broadcasters

Content:  Use a combination of three or four different practices to control pests effectively.  To choose the best methods it is important to learn about the pest, its natural enemies, its relation to the crop, and the crop itself.


These days many farmers use only one type of pest control. Many use only chemical pesticides. But using only pesticides can cause problems.

At first, you might find that chemical pesticides work well. But pesticides do not only kill bad pests: they also kill many of the good or friendly insects which eat the pests. So you end up spending more money to buy more pesticides to do the work that friendly insects were doing before.

Also, over time pests can become resistant to pesticides. Pesticides kill the weaker ones, leaving the strongest to breed a new generation of pests healthy enough to resist the pesticide. So the pesticides are no longer effective.

That is what can happen if you depend on just one method of pest control, such as chemical pesticides. But there is better way to deal with the problem of pests. It is called integrated pest management.

What is Integrated Pest Management?
The idea of integrated pest management is to use several methods of pest control at the same time. You might want to use three or four methods. Rotating your crops, fertilizing the soil, planting many different crops and crop varieties, picking pests off your plants by hand, and applying some chemical pesticides are all good ways to control pests. And a combination of three or four of these methods is best because if one method fails for some reason, the other methods will continue to protect your crop.

Learn about insect pests:
How do you decide which pest control methods will be most effective in your field? The most important thing to do is to learn about the pest. Learn about the pest’s life cycle, where it lives, and its habits. Also, it is important to learn about the pest’s natural enemies, the relation between the pest and the crop, and the crop itself.

You can learn about the pest by watching it carefully in the field and by talking to other farmers or agronomists. You may be surprised to learn that some insects have three different stages of development, while others have four stages. And that some insects have mouths that suck and others have mouths that bite. An extension worker might help you learn more about the pests in your region.

Why is it so important to learn about the pest? Because if you know what a pest looks like at each stage of its development, you can decide at which stage it is easiest to control. Some pests are easier to control as adults, some as eggs, and some as larvae.

For example, once you realize that the June Beetle and the white grub (Phyllophaga spp) that are eating the roots of your maize are actually the same pest at different stages of development, you can see that it is easier and more effective to trap the pest when it is an adult, at the beetle stage. June Beetles fly around in big groups in the spring. They are attracted to light, and you can catch them with simple traps. So it is easier to deal with this pest in the beetle stage than to dig around in the earth to catch it in the white grub stage.

You will also want to know when the insect feeds on the plant. Does it feed in the day or at night? In what season is it a problem? You want to make sure you are not wasting time or money controlling a pest when it is not even bothering the plant.

You can learn more about the life cycle of a pest by catching a few of one type. Keep them in a can or bottle with some earth and some leaves. Punch some holes in the top of the container. Watch how the insects change and how they look at different stages of their life.

The other thing to do when you are deciding what pest control methods to use is experiment with a few different methods. Find out what combination works best for you. Exchange ideas with yourneighbours. When you use Integrated Pest Management as your pest control strategy you need to be creative and consider the problems carefully.

Remember! Insects are not just enemies that will destroy your crops. They are part of the natural environment. Like you, they need to eat. In a balanced environment, both insects and peoplehave enough to eat. Using only chemical pesticides changes the balance in nature. But by using integrated pest management, you can find ways to work with, instead of against nature.


The information in this script is from ALTERTEC.  ALTERTEC is a non‑profit, non‑governmental organization which works with Guatemalan farmers to promote integrated, ecological agriculture.

Information Sources

Interview with Hermogenes Castillo, P.Agr., Coordinador Regional, ALTERTEC, Aptdo. Postal 304, Quetzaltenango, GUATEMALA.

Manejo integrado de plagas insectiles (1992, 95 pages), ALTERTEC, 2a Calle 10‑14, Zona 1, Ciudad de Guatemala, GUATEMALA