Do you have insects in your garden that are bugging you and you’re not sure what they are or how to deal with them? Take comfort, you’re not alone.
This is the time of year that we start seeing quite a few insect problems as populations grow. So the questions we usually have are “what is this bug, and should I be concerned, and what should I do about it?”
It’s important to know what insect you have before deciding whether to kill, ignore, or enjoy the presence of the little creature. It really is a bug eat bug world out there so don’t get too anxious to kill every critter that crawls or flies.
For example, there’s a good chance that you will encounter robber flies in your garden from time to time. These one to two inch long fly-like creatures can be quite intimidating if you don’t realize they’re one of the good guys. They’re fast fliers, which enables them to grab insects like miller moths from the sky. Their large, almost spooky, eyes help them to see their prey.
I’ve been seeing quite a few thrips (always pronounced plural). Your plants may have them and you may not even know it because the insect is so small. If the flower blooms fail to open, or look black and mushy, it could be because of thrips. Onion tops and gladiolus leaves may have long strips of stippled, dying tissue. Thrips can often be found hiding deep in the flower so gently pull the flower petals apart to check for the insects. What you may find is an insect that looks like a very small tan line moving about.
If you cut a flower and bring it in the house for an arrangement you may find “tan lines” scurrying across the counter. These are actually the little thrips. They feed by piercing the plant and sucking the sap from it. It’s kind of like the action of a kid drinking from a juice box. Because thrips are capable of transmitting some bad diseases to your tomatoes and can damage your flowers, you’ll want to control them. Yellow or blue sticky traps will give some results. Spinosad or pyriproxifen (growth regulator) will also give satisfactory results.
People have been calling me about geranium or tobacco budworms on the buds and petals of their geraniums and petunias, as well as a few other flowers.
To check for the caterpillars look for small holes in the buds or on the leaves. If the worms are present they can be pulled off of the plant and dropped into soapy water. You’ll be most likely to spot them at dusk when they’re most active. During daylight hours, they usually hide around the base of the plant. They’re resistant to most garden insecticides, however Bt (Bacillus thuringiensis) insecticides can provide good control. Synthetic pyrethrins, also known as pyrethroid insecticides, can also provide control. They’re developing varieties of bedding plants that are resistant to the budworms, which is good news if you’ve been battling them.
Earwigs are considered both beneficial and yet a bit of a problem. You may not notice them because they’re more active at night and will hide under the bark of a tree or under debris in the garden. They feed on a wide variety of plants and occasionally cause injury to leafy plants such as lettuce and some flower blossoms. You may also find them hiding in the tip of an ear of corn. They will feed on pests such as aphids, mites and insect eggs, which is a good thing. But, if you choose to control earwigs, a trap baited with wheat bran or wheat germ placed inside a rolled up dampened newspaper works well. Just be sure to toss the trap into a sealed bag every 2-3 days and throw it in the trash. Another trap would be to place vegetable oil in a small cup or shallow can like a tuna fish can. Sink it into the ground keeping the level of the oil at least an inch below the surface. The idea is, the earwigs will crawl into the can and not be able to crawl out. Check and dispose of the traps regularly.
Spider mites love drought stressed plants, especially if they’re growing in a sunny, hot location. If your plant is looking a little crispy or needles on your evergreen look more gray than green, you might have spider mites. Look closer for webbing or black dots that are smaller than a pinhead. You might want to hold a piece of white paper under the leaf or needles and tap the plant. If a small black dot drops off and begins crawling, you probably have spider mites. Often times, simply spraying the underside of the leaves or needles of a tree with a strong stream of water every few days for a couple of weeks, and increasing the irrigation a bit, will take care of the problem. A miticide insecticide can be very effective for control. Just be sure the product that you spray with is labeled for spider mites. Using the wrong product can actually increase the mite populations.
Aphids have caused some curled, distorted leaves on trees. If you can unroll the leaf and see small insects living there, they’re probably aphids. If there are no insects in the leaf it could be herbicide drift damage. If you find the damage was caused by aphids rather than herbicide, consider spraying the tree with dormant oil next spring. This will kill the eggs of these difficult to control aphids or any adults that may have over-wintered on the tree.
Remember, a few insects on your plants is normal. However, if they’re doing damage it’s time to identify them and perhaps do something about it. And, make sure you’re going after the true pests, not the good guys! If you’re not sure what your insect is, put it in a sealed container or baggie and bring it to the CSU Extension office for some help.
Linda Corwine McIntosh is a commercial pesticide applicator, ISA certified arborist, and an advanced master gardener.