Garden Insect 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

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.

     


Wingless and Winged Aphids

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 lifecycle is quite interesting but will not be discussed here. Members of the cabbage family (broccoli, brussel sprouts, cabbage, mustards 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. Then let your ladybugs out of their package and they will drink and stay around to munch on your bugs!

    


The Harlequin and Stink Bug

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.
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 organic substance rotenone can be very effective. Lately we have not been recommending the use of Rotenone due to the harm it can cause bees and other beneficial insects.

              



Tomato or Tobacco Hornworm, Cabbage Butterfly and Larva and Black Swallowtail Butterfly and Larva

The Tomato Hornworm 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.
The Cabbage butterfly's larva, the cabbage worm is harder to spot. They can be found eating on any of the cabbage family. If you see a white butterfly flitting around your garden then you probably have cabbage worms somewhere. They can really hide in your broccoli or cabbage. Larry uses BT (Bacillus thuringiensis) to control these critters. This is a bacteria that is harmful to the larval stages of most butterflies and moths. It is harmless to humans and other animals. Be careful and thoughtful with your use of this product. It is sold under the trade name, "Dipel Dust", or "Thuricide".

The Black Swallowtail butterfly lays its eggs on members of the Parsley family. This includes parsley, cilantro, dill and carrots. The caterpillars are easy to spot and pick off plants. Since they become such magnificent butterflies Larry just picks them off his cilantro and puts the caterpillars on one of his numerous dill plants.

      


Mexican Bean Beetle and Spotted Cucumber 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.
The Spotted Cucumber beetle is less a problem for us. Their larval form feeds on the roots of many plants (usually the cucumber, melon and maybe corn).
For both of these beetles we choose to just pick them off the plants.