Pest Control vs. Integrated Pest Management

Praying MantisThe old thinking of pest control, “see a pest, kill the pest,” has got to change to the new thinking of integrated pest management.

So what is integrated pest management? Simply put it is using all available methods to keep pests below damaging levels. Methods include such things as choosing plants resistant to some of their natural enemies and suited for the environment. Cultural control, such as cleaning needles from under pines in the fall. Predator introduction and maintenance (keeping some plants in the garden in flower for the whole season is a great way to keep predators around as many of our best predators have juvenile stages that feed on nectar). Monitoring and determining the damaging threshold of a pest. The correct use of fertilizer and water (yes these can both affect pest populations), and the use of pesticides.

Why would you want to manage pests and not just kill them?

Good question.

Well the first thing is that the old pest control strategy was wrought with problems: Just killing the pest does not always work in the long run. Pests become resistant to chemicals and you can wipe out the predators with “just kill it” strategies. Then you end up with super bugs and no predators.

Even the great DDT that many farmers and mosquito control people whined about when it was removed from the market was, at that point, becoming fairly useless in controlling mosquitoes. Already there was a great deal of resistance in mosquito and other insect populations and this was destined to get worse.

Killing one pest outright can lead to the multiplication of another pest that was present but not a problem. For example lets take the case of the Hemlock Eriophyid Mite and the Two Spotted Mite. So you want to kill the Eriophyid and you choose Sevin as it really does a great job killing this mite. Sevin however does not effect Two Spotted Mites in the least, but is horrible on this mite’s predators. Now you have no Eriophid Mites but a population explosion of Two Spotted Mite. So you just traded one problem for another and spent money for the privilege.

Not to mention that Eriophyid Mites will rarely build to populations that severely damage a plant. Note that I am not badmouthing Sevin, used properly for the right pest at the right time this product can be the suitable choice.

Does this mean that in integrated pest management we do not ever try to kill every pest?

The answer to that is no, sometimes it is the right way to go, but we choose our battles and the results we want from them more carefully.

For example, invasive species are one reason where it might be good to use a wipe out strategy, as these pests usually have few or no natural enemies. If there were a product that would kill every Asian Longhorn Beetle but decimate natural predators in the area it would be the obvious choice to use the chemical even with the loss of predators. Asian longhorn beetle will destroy all favorable trees in its path, like a B science fiction movie. So even though native pests would, for a time, get worse due to the predator loss these natural predators would recover and nature would resume its balance.

Levels of acceptable damage are different and depend apon the pest, crop, use, personal preference and other factors. One dandelion on a golf green is one too many, but would not even be noticed on a highway median. One Asian Longhorned Beetle is one too many, but ten European corn borer in a patch of Zinnia may be acceptable.

The correct application of Integrated Management may leave a residual population of pests in an area. The good technician will evaluate the pest, the population, the available natural predators and the potential for the pest to reach damaging levels for the situation before deciding if and how to treat the problem.

So if in integrated pest management we don’t try to kill all the pests, why not just go totally organic and let nature take care of everything? Under some circumstances we can and do, but we have changed our environments and, in turn, how nature can deal with problems. Even in a balanced system there are ebbs and flows in pest populations, and sometimes great losses. We often expect and need more than nature can give. If you look at an untreated apple tree, there will be apples on it but most people would not eat them even though they are quite edible; worms, apple scab and all.

Though there is still a lot of research to be done in the integrated pest management field, this approach has proven itself to be better then conventional pest control in many instances. The proof to this is that most farmers have adopted the strategy and have found that they have increased crop yields and reduced expenses.

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