By Alton Sparks
University of Georgia
Controlling insects in your vegetable garden can be a challenge.
From strictly nonchemical to “washday” applications of
insecticides, the approaches to insect control are as varied as
the people who garden.
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Many homeowners accept some insect damage, while others will
tolerate none. The level of damage you deem acceptable largely
determines the level of control required and can limit your
options.
You have five basic options for controlling insects. Besides
sanitation, there are cultural, mechanical (or physical),
biological and chemical control.
Sanitation
With the loss of Dursban and Diazinon, home gardeners have no
legal insecticides to control soil pests like white grubs and
wireworms. Good sanitation is the first approach for controlling
these pests and will help with others, too.
Remove all vegetation, including weeds, from your garden site
when it’s not in use. This makes the garden less hospitable for
these insects. If these pests move into the garden after the
plants are well established, damage is much less severe.
Cultural
These controls include selecting plants that resist or tolerate
certain insects. And planting transplants, rather than seeds,
avoids several pests that can attack germinating seeds and young
seedlings.
Early transplanting and finishing the crop earlier in the year
avoids pest buildup in late spring and summer. If you
direct-seed, it may be better to delay planting so that seeds
germinate and grow fast, shortening the time they’re susceptible
to seedling pests.
Mechanical
These are often the simplest and most overlooked controls.
Physical barriers can prevent pests from reaching the crop until
it’s large enough to resist significant damage.
In a small garden, or if pest populations are low, just pick
pests off plants and squash them. It’s a simple, excellent
approach for many home gardens.
Biological
Beneficial insects can provide efficient control. They feed on
the insects that cause plant damage. But manipulating the
beneficial insects can be tough. Both pests and beneficials
readily move.
The most common and best approach to biological control is simply
managing pests in a way that protects naturally occurring
beneficial insects. If you see pests in the garden, check to see
if anything is attacking them. Sometimes, all that’s needed is a
little time for nature to bring a pest population under control.
Chemical
Insecticidal control is still one of the quickest, easiest ways
to control insects. But use it only when necessary.
Sticking to a strict spray schedule is a waste of money in most
cases. It may actually create pest problems by killing
beneficials. And it’s generally not good for the environment.
Read and follow the label of each pesticide you use. Pay close
attention to the crops a pesticide can and can’t be used on and
the amount of time required between the last application and
harvest.
How all of these approaches can best be integrated into your
final insect management program depends on your needs for pest
control, crop quality and overall safety.
Gardeners willing to tolerate some insect damage can generally
grow their plants with minimal use of insecticides. Those who
require pest-free plants are often limited to a heavy reliance on
pesticides.
(Alton Sparks is a Cooperative Extension entomologist with the
University of Georgia College of Agricultural and Environmental
Sciences.)
