Insects and Pests

How to Prevent…Identify…Control

Quick Tips on Prevention

  • Never plant the same plants in the same area two years in a row.

  • Crowded plants foster disease and hiding places for many insects.

  • Remove diseased plants from your garden.

  • Healthy soil fosters healthy plants that can better fight off an insect attack.

  • Learn about companion planting. Chives inter-planted with lettuce and nasturtiums inter-planted with broccoli can ward off some bugs.

  • Inspect your vegetable plants for pests every three or four days. Look on the underside of the leaves too!

  • Use the least invasive method possible to control pests (first pick off by hand, then spray with water, then use the least toxic organic insecticide as a last resort).

  • Many organic insecticides will kill the beneficial insects (like bees and ladybugs) too. Read the labels and choose wisely.

Learning to Identify and Control Some Common Insect Pests

Cutworm and Grub

Cutworm and Grub.png

The cutworms are actually the plump, earth-colored larvae of several species of medium sized moths. They are about 1-2 inches long. The larvae live in the soil and are active at night. They emerge from the soil and cut off plants at the surface. Tomato, pepper, broccoli and squash plants are the most vulnerable. The best control is to insert a cardboard collar about an inch below the soil and sticking about 2 inches above the soil. After the plants are about a month old the collar is no longer needed.

The grub is the larval form of several species of May or June bugs. These inch long grubs live in the soil and feed on the roots of many plants. Most people don’t know that they have an infestation of grubs until their plants are wilting and dying. Scoop up 8 inches of soil and see if you can spot any grubs before taking any action. Deep cultivation in the fall can destroy many of the over-wintering grubs. Garlic or chives inter-planted with your veggies seems to help. There are some strong chemicals that will do the trick but again you have to wait several weeks before harvesting. We don’t recommend using any of the off shelf chemicals.



Aphids are about the size of a radish seed and vary in color from light green to black. They weaken the plants by sucking the juice out of them. They can cause the leaves to curl, stunt its growth or even greatly reduce the production of flowers or fruit. Their life cycle is quite interesting but will not be discussed here. Members of the cabbage family (broccoli, Brussels sprouts, cabbage, mustard and kale) seem to attract them more than other plants. Inspect your plants often. One female aphid can produce up to 100 offspring in one month. Each offspring can reach maturity in just a week. You do the math and you will see that this is one insect that you will need to get under control quick.
Thank goodness that this one is easy to control. Larry first uses a mild solution of soapy water to spray on his infected crops. If this is not effective he uses a pyrethrum (made from chrysanthemums) spray. This is a high powered organic that could harm some of your beneficial insects. Spray only if needed. It is harmless to humans however.

Try using ladybugs in your garden. They love to eat aphids. If you buy ladybugs, here is a trick to keep them around. In the early summer evening, hand spray your infected plants and surrounding plants with a sugar-water solution. Let your ladybugs out of their package and they will drink and stay around to munch on your bugs!

The Harlequin and Stink Bug

Harlequin Adults

Harlequin Adults

These bugs also suck juice out of your plants. They seem to love squash and pumpkins the most but can be found on bean and cabbage as well. Notice the eggs in the picture of the Harlequin bug. They are shaped like little kegs! If you see the eggs just rub them off.

Harlequin Nymphs

Harlequin Nymphs

These bugs are easy to spot. Again be sure to look under and between the leaves. Picking them off and disposing of them is one method that many of us use.

The Tomato Hornworm

Tomato Hornworm

Tomato Hornworm

This caterpillar grows to about 4 inches long and can eat up your tomato plants. After seeing chewed leaves look for this green caterpillar. Just pick them off and dispose of them. They will grow into the sphinx moth.

Sphinx Moth

Sphinx Moth

Colorado Bean Beetle

Colorado Bean Beetle

Colorado Bean Beetle

These beetles are both about the size of a pea. The Mexican Bean beetle, in its larval form, can absolutely ruin an entire bean crop if left unchecked. It is important to inspect your beans often. Look for the larval form. They are usually an orange-yellow and found on the undersides of the bean leaves. The leaves will look skeletonized.

Thu Tran