HomeCommon Insects
Aphid Aphids are less than 1/10" long. They have soft pear-shaped bodies and depending on the species may be green, brown, black, yellow or pink. Aphids suck the juice from leaves, fruit and stems. The foliage will curl, pucker and yellow and the plants vigor will decline. Light infestations are easy to control. Simply spray infested plants vigorously with water three times, once every other day, in the early morning. If this doesn't take care of them, use insecticidal soap every two to three days for two weeks. As a last resort spray with pyrethrum.
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Asparagus Beetle Beetles make up 40% of all insects. They come in a variety of colors, shapes and sizes, but in general, all have hard, opaque wing covers that meet straight in line down the middle of their backs. Beetles will eat leaves, stalks and flowers. You may find damage ranging from small holes in leaves of infested plants to large chunks ripped off the edges of leaves to defoliation of the entire plant. Handpicking will immediately eliminate a lot if not all the insects from an infested plant. You can try spraying plants with a mixture of pyrethrum and isopropyl alcohol, which should be applied every three to five days for two weeks. Make this solution by combining two parts alcohol with one part water and adding pyrethrum in the concentration recommended on the bottle.
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Bagworm Bagworms are the larvae of moths. They spin silken bags around themselves, to which they attach pieces of the the leaves they are eating. Full-grown, they measure 1- 1 1/4" inches. Their bodies are brown with that portion inside the bag lighter than the rest. The best way to remove these pests is to simply handpick the bags with the insects and destroy them. Spray with Bt (Bacillus thuringiensis) from May 1 to June 1. Spray once, and repeat seven to ten days later if live bagworms are still present.
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Beetle Beetles make up 40% of all insects. They come in a variety of colors, shapes and sizes, but in general, all have hard, opaque wing covers that meet straight in line down the middle of their backs. Beetles will eat leaves, stalks and flowers. You may find damage ranging from small holes in leaves of infested plants to large chunks ripped off the edges of leaves to defoliation of the entire plant. Handpicking will immediately eliminate a lot if not all the insects from an infested plant. You can try spraying plants with a mixture of pyrethrum and isopropyl alcohol, which should be applied every three to five days for two weeks. Make this solution by combining two parts alcohol with one part water and adding pyrethrum in the concentration recommended on the bottle.
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Black Vine Weevil Weevils, also called snout beetles, have long slender snouts at the end of which are their mouth parts. Their tear shaped black or brown bodies are covered with a hard shell, and they measure 1/10 to 1/4 inch in length. The adults feed at night and curl up under plant debris during the day. Most species will play dead when disturbed, folding their legs and dropping to the ground. The larvae also feeds on plants. They are legless about 1/2 inches long and white to pink in color with brown heads. Adult weevils eat holes or notches in leaves; some species roll or curl them. When abundant they can defoliate plants. The larvae carve a zigzag path into roots, fruit, or stems. Infested plants wilt and will pull out of the ground easily. Two or three hours after dark, when the weevils have moved up into the plant, place a strip of cardboard coated with a sticky material, such as tanglefoot, around the trunk, the tanglefoot will tangle their feet. Make sure the trap fits snugly around the plant or the weevils will crawl underneath it. Or a band of a sticky substance such as tanglefoot applied around the trunk or stems of the plant will prevent weevils from climbing up for their nightly feed. |
Boxelder Bug Boxelder bugs look like squash bugs. They are brownish black with red markings and measure about 1/2" in length. The nymphs are bright red and in fall you will often find them swarming around the bases of trees, fence posts or walls. Holes in leaves, flowers or fruit of your trees might mean boxelder bugs. These pests will infest maples and ashes and sometimes invade houses in large numbers. Control boxelder bugs by handpicking them if there are a few or by spraying infested plants with insecticidal soap or pyrethrum. |
Bronze Birch Borer Borers are the larvae of many different kinds of beetles and moths. They range in length from 1/2" to more than 2". Usually they are white or pink with brown heads. When borers tunnel their way into the soft stem of an herbaceous plant, they weaken the stem and often break it. If you notice certain plants are bent over or that they have wilted suddenly, check the stems for small holes, which might have been drilled by borers. Around the edge of holes you will often see frass (excrement) or sap that has been pushed out by the insect. To control borers in most situations, make a thorough examination of the shrub or tree before the spring season arrives and cut and burn any dying or unhealthy-looking stems or branches that may contain borers. During the summer check for borer holes and cut into them with a sharp knife. If the tunnels are fairly straight you can kill borers by probing the hole with a flexible wire. By using a hooked wire you can catch the worms and pull them out. If you find that the tunnels wind all over inside the trunk and you simply won't be able to track them down inject beneficial nematodes into each borer hole and plug the hole with chewing gum or putty. |
Carpenter Ant Ants themselves don't do a lot of damage to plants, but they are indirectly responsible for certain problems in your landscape. Ants love sweets and are particularly fond of the honeydew produced by aphids. |
Caterpillar
Caterpillars will eat the foliage and stems of just about any plant in your landscape. Holes in leaves and chunks taken from along their edges are typical signs of caterpillar attack. In a very short period of time, caterpillars can defoliate a plant. Handpicking most caterpillars can keep them from getting out of hand if you catch the infestation right away. Bt kills most leaf-eating caterpillars. Dust all parts of the leaves, especially the undersides, reapplying the dust after rains. |
Chinch Bug Chinch bugs are so small and inconspicuous that they can destroy a lawn right under your eyes without being noticed. Suspect chinch bugs when you see large distinct circular patches primarily in the sunny areas of your lawn, that turn yellow, then brown and then die. These patches often appear first near sidewalks and streets where heat is reflected onto the lawn, but soon they spread outward into the rest of the lawn. Monitor to catch cinch bug infestation as soon as possible. Control heavy infestations with insecticidal soap. Spray the affected area of your lawn every two to three days for three weeks. |
Cicada Cicada's are large insects that appear in late spring/early summer and make a lot of noise. They can fly and will infest residential neighborhoods for a few months every summer. Though they don't sting, most people are afraid of them. Their large size seems to scare people and when one is seen, it usually gets a lot a attention. Cicadas are not attractive. They have an almost alien look with bulging eyes and a hard, shell like skin. Large and long clear wings don't hide their short, stubby body. These insects are only active for a short time each year but when present, you know they are here!!! Cicada's are 2 1/2" to 3" long and easy to see. When active, they will fly from tree to tree in search of a mate and food. Adult cicada's eat mostly sap. Once females have mated and want to lay eggs, they seek out small branches of trees and shrubs for egg laying. The plants targeted will become food for their young. They will fly from tree to tree, living their complete adulthood in just a few months. When they are spent and die off as summer progresses, adult cicadas will be seen on the ground being preyed upon by birds and other insects. Female cicadas will lay 500 or more eggs once able. These eggs are deposited through a needle like injector, called an ovipositor, and 10 to 20 eggs are sent into likely host trees when she makes her injections. Females will choose small branches and twigs for making these deposits. Though large hardwoods and other mature, healthy trees probably won't be hurt by this activity, young plants can suffer. Since the females will inject through several locations once they find a suitable limb or branch, these same branches will probably die in a few months due to the excessive punctures. Eggs will hatch in 1-2 months and larva will emerge falling to the soil. There they will burrow and feed on the fine shallow root system of the host tree or shrub. As they grow, the larva will move deeper and deeper into the ground where they will stay till fully mature. |
Corn Root Aphid These aphids live in the soil and attack roots, bulbs and corms. Ants often bring these soil-dwelling aphids to your plants. Plants infested with these show the same symptoms as those attacked by above-ground aphids- curled, yellow foliage. Light infestations are easy to control. Simply spray infested plants vigorously with water three times, once every other day, in the early morning. If this doesn't take care of them, use insecticidal soap every two to three days for two weeks. As a last resort spray with pyrethrum.
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Elm Leaf Beetle Beetles make up 40% of all insects. They come in a variety of colors, shapes and sizes, but in general, all have hard, opaque wing covers that meet straight in line down the middle of their backs. Beetles will eat leaves, stalks and flowers. You may find damage ranging from small holes in leaves of infested plants to large chunks ripped off the edges of leaves to defoliation of the entire plant. Handpicking will immediately eliminate a lot if not all the insects from an infested plant. You can try spraying plants with a mixture of pyrethrum and isopropyl alcohol, which should be applied every three to five days for two weeks. Make this solution by combining two parts alcohol with one part water and adding pyrethrum in the concentration recommended on the bottle.
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Fall Webworm The fall webworm, Hyphantria cunea (Drury), is most often discovered when the unsightly, light gray, silken webs on the trees in late summer and early fall are observed. Webworms enclose leaves and small branches in their nests, unlike the tent caterpillars which make a smaller nest in the crotch of branches This pest usually eats leaves late in the season and the nests are generally concentrated to limited areas. Because of this, little real damage is done to most trees. However, the nests can look very unsightly and multiple generations in long summers can lead to significant defoliation. Removal of Nests - Small nests can be pruned out of small to medium trees. Monitor trees early to detect the nests when only several leaves are involved. These small nests can be easily crushed. Do not burn or torch the nests in trees as this may do additional damage to the tree. Over 80 species of parasites and predators have been identified in North America. Social wasps (yellow jackets and paper nest wasps), birds, predatory stink bugs and parasitic flies and wasps are the most important. Delay destruction of wasp nests until August when social wasps change from carnivores to sugar feeders. Try to withhold contact insecticide sprays until it is certain that predators and parasites are not present in sufficient numbers to control the webworms. The bacterial insecticide, Bt, is quite effective against fall webworms if it is applied when the larvae are small. Use formulations with UV protectants and thoroughly cover leaves next to nests. As these leaves are incorporated into the nest and eaten, the Bt will be ingested.
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Lace Bug Lace bugs are quite appropriately named. Their delicate wings resemble pieces of lace. These insects have square-shaped bodies, only about 3/16" long. Lace bugs suck sap from the undersides of leaves causing foliage to turn pale or mottled. A reddish orange discoloration on the undersides of leaves is a good sign that your plants are indeed infested with lace bugs. The top surfaces take on a mottled appearance, much as if they had been sprinkled with white pepper. You may also find shiny spots of brown excrement on the bottom surfaces of leaves. You can simply crush lace bugs as you find them, or spray infested plants with insecticidal soap, making two applications one to two weeks apart. If the infestation is so serious that the soap can't control it, spray plants with pyrethrum every seven to ten days until symptoms disappear. |
Lady Bug Ladybugs are beneficial to organic gardeners because most species are insectivores consuming aphids, fruitflys and thrips and other tiny plant-sucking insects that damage crops. In fact, their name is derived from "Beetle of Our Lady", recognising their role in saving crops from destruction. Today, they are commercially available from a variety of suppliers. In agriculture, coccinellids, like other beetles, can find protection in beetle banks. As the family name suggests, they are usually quite round in shape. Because they are useful, colourful, and harmless to humans, coccinellids are typically considered cute even by people who hate most insects. Some people consider them to be a sign of good luck.
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Leaf Miner (Adult) Leafminers are the larvae of various insects: small black flies, moths, sawflies or beetles. Adults will usually lay eggs on the undersides of leaves. The larvae that hatch are green or black and about 1/8" long. Upon emerging they tunnel into the leaves between the upper and lower surfaces and feed on the inside of leaves. White or brown tunnels or blotches can be seen through the surface of the leaves that have been mined by leafminers. Eventually the leaves will blister or curl, turn brown and dies. To remove leafminers, remove the infested leaves. Spray with insecticidal soap to kill any adults that might lay eggs on your plants.
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Scale Scale insects are related to mealybugs and aphids although they don't look very much like either of these insects. Actually they don't look like insects at all, but like little bumps. These insects have rounded waxy shells, which protect them while they feed. They usually gather in groups on the stems and leaves of plants. Under their shells, scale insects either lay eggs or bear live nymphs. These nymphs crawl to other parts of the plant and settle down to build their own shells. If you discover scale insects before too many of them have infested your plants, simply scrape them off with your fingernail or with a cotton swab dipped in rubbing alcohol. If the pests are numerous, spray infested plants with a mixture of alcohol and insecticidal soap every three days for two weeks. Insecticidal Soap and Alcohol: Mix 1 cup Isopropyl alcohol and 1/2 tsp insecticidal soap in 1 quart water and apply it to infested plants every three days for two weeks. |
Red Bud Leaf Roller Leaf rollers are caterpillars or moths. They may be light to dark green or cream, black to yellow in color and grow to a length of 3/8" to 1 3/4". The adult moths are small - 1/4 to 1/2" long, with brown or gray wings. These insects roll leaves around themselves for protection while they are in their pupal stage. You'll probably notice first an infestation when you see that the leaves on your trees are rolled up. Once they've built little homes for themselves, they'll go out and chew holes in flower buds and leaves. These pests have a fair appetite and can skeletonize leaves, which will turn brown and drop in late summer. Crush leaf rollers as you find them , and spray plants with Bt (bacillus thuringiensis). Neem Oil is quite effective as well. If leaf rollers are a common problem in your yard, spray vulnerable plants with Bt before you expect the caterpillars to begin feeding. Leaf rollers overwinter as pupae in garden debris and the moths appear in the spring. |
Spotted Cucumber Beetle Beetles make up 40% of all insects. They come in a variety of colors, shapes and sizes, but in general, all have hard, opaque wing covers that meet straight in line down the middle of their backs. Beetles will eat leaves, stalks and flowers. You may find damage ranging from small holes in leaves of infested plants to large chunks ripped off the edges of leaves to defoliation of the entire plant. Handpicking will immediately eliminate a lot if not all the insects from an infested plant. You can try spraying plants with a mixture of pyrethrum and isopropyl alcohol, which should be applied every three to five days for two weeks. Make this solution by combining two parts alcohol with one part water and adding pyrethrum in the concentration recommended on the bottle.
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Sunflower Beetle Beetles make up 40% of all insects. They come in a variety of colors, shapes and sizes, but in general, all have hard, opaque wing covers that meet straight in line down the middle of their backs. Beetles will eat leaves, stalks and flowers. You may find damage ranging from small holes in leaves of infested plants to large chunks ripped off the edges of leaves to defoliation of the entire plant. Handpicking will immediately eliminate a lot if not all the insects from an infested plant. You can try spraying plants with a mixture of pyrethrum and isopropyl alcohol, which should be applied every three to five days for two weeks. Make this solution by combining two parts alcohol with one part water and adding pyrethrum in the concentration recommended on the bottle.
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Sunflower Seed Weevil Weevils, also called snout beetles, have long slender snouts at the end of which are their mouth parts. Their tear shaped black or brown bodies are covered with a hard shell, and they measure 1/10 to 1/4 inch in length. The adults feed at night and curl up under plant debris during the day. Most species will play dead when disturbed, folding their legs and dropping to the ground. The larvae also feeds on plants. They are legless about 1/2 inches long and white to pink in color with brown heads. Adult weevils eat holes or notches in leaves; some species roll or curl them. When abundant they can defoliate plants. The larvae carve a zigzag path into roots, fruit, or stems. Infested plants wilt and will pull out of the ground easily. Two or three hours after dark, when the weevils have moved up into the plant, place a strip of cardboard coated with a sticky material, such as tanglefoot, around the trunk, the tanglefoot will tangle their feet. Make sure the trap fits snugly around the plant or the weevils will crawl underneath it. Or a band of a sticky substance such as tanglefoot applied around the trunk or stems of the plant will prevent weevils from climbing up for their nightly feed.
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Tobacco Hornworm Tomato/tobacco hornworms are the largest caterpillars found in this area and can measure up to 4 inches in length. The prominent "horn" on the rear of both gives them their name. The size of these garden pests allow them to quickly defoliate tomatoes, potatoes, eggplants, and peppers. Occasionally, they may also feed on green fruit. Gardeners are likely to spot the large areas of damage at the top of a plant before they see the culprit. Hornworms are often difficult to see because of their protective coloring. Not much for the heat of direct sunlight, they tend to feed on the interior of the plant during the day and are more easily spotted when they move to the outside of the plant at dawn and dusk
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Yellow Sugarcane Aphid These aphids live in the soil and attack roots, bulbs and corms. Ants often bring these soil-dwelling aphids to your plants. Plants infested with these show the same symptoms as those attacked by above-ground aphids- curled, yellow foliage. Light infestations are easy to control. Simply spray infested plants vigorously with water three times, once every other day, in the early morning. If this doesn't take care of them, use insecticidal soap every two to three days for two weeks. As a last resort spray with pyrethrum.
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Armyworm Armyworms cause problems in lawns. They sometimes travel in large groups and usually feed at night. Their work on your lawn shows up as round, bare areas. In large numbers they will eat the grass right down to the soil. If you lift up the dead sod in these areas, you'll find armyworms in the soil. Spray the infested lawn or plants with Bt (bacillus thuringiensis) every 10-14 days until the worms are under control. Reapply Bt after rain. |
Cutworm Cutworms work quickly and invisibly. Cutworms generally attack seedlings, severing the stems at or below the level of the soil. They work at night, so you won't catch them in the act of hacking down your landscape plants. Options: Cornmeal or Bran Trap: After putting out transplants, sprinkle 1/2 tsp cornmeal or bran meal around plant. Apply it in a circle leading away from the stem of the plant. Cutworms will eat the meal, which will swell inside them and kill them. You can also handpick cutworms at night. Look for them near the base of the plants and just under the soil surface. Bt (bacillus thuringiensis) effectively controls some species. Dust seedlings and transplants at the soil level. |
 
Japanese Beetle The Japanese Beetle is about 1/2" long. It is a shiny metallic green and has copper-colored wings. The grub is grayish and has a dark brown head. Two rows of spines form a V on the underside of the grub's last abdominal segment. Handpick beetles from plants and drop them into a pail of soapy water. Treat the soil of lawns and gardens with milky spore disease or with beneficial nematodes. Apply Neem spray to infested plants twice, at weekly or longer intervals until pests are under control. |
MealyBug They have flattened oval bodies covered with white waxy powder. Short soft spines protrude from their edges. Mealybugs feed on stems, branches and leaves and can often be found in leaf axils and other protected sites. They tend to congregate, and a group of them looks like a mass of cotton. The most obvious sign of a mealybug attack is perhaps the mealybugs themselves, with their white cottony appearance. They gather in masses on the stems, branches and leaves of the plants they attack. As they suck sap from the leaves and stems, plants lose their vigor. They do not grow well and may die if the infestation is severe. You may also find ants or mold on your plants. They are attracted to the honeydew secretred by mealybugs. Control mealybugs by spraying infested plants with insecticidal soap or pyrethrum three times at seven to ten day intervals. |
Mites Mites are not true insects; they are relatives of spiders and belong to the arachnid family. Mites attack many kinds of plants, feeding at leaf undersides, flowers, bulbs and corms, and at the blossom ends of fruit. As they feed, they inject toxins into plant tissues, which cause discoloration and distortion. Mites love hot, dry conditions, especially in greenhouses. The hotter it is, the more rapidly they develop from egg to adult. If you see white or yellow stippling or red spots on the upper surfaces of leaves, your plant is probably infested with mites. Leaves, shoots and flowers may be swathed in fine webbing. Overall yellowing of the leaves begin along the veins and then spreads over the entire surface. Start control measures as soon as you notice the first stippling of leaves. Spray infested plants in the early morning with a forceful spray of water to knock mites from the leaves. Repeat this for three days. If mites are still around, spray with insecticidal soap. A spray of insecticidal soap mixed with light horticultural oil works as a dormant spray against eggs and newly hatched nymphs.
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Nematodes Actually nematodes aren't insects. They are microscopic wormlike organisms. They have whitish, translucent, unsegmented bodies covered by a touch cuticle. Most nematodes are innocuous, living out their lives in fresh water, or salt water, or in soil. Some are beneficial, parasitizing a long list of pest insects. A number of types are plant pests. One of the most common pest nematode is the root knot nematode. It lives in the soil and soon after hatching the worms enter the roots of nearby plants. Pest nematodes attack all plant parts, stems, leaves, buds, roots, bulbs and corms. A few cause galls to develop on roots or leaves. In general, plants infested with nematodes, look sickly, wilted or stunted. Their foliage turns yellow or bronze, and they decline slowly and die. If the root system has been attacked it will develop poorly and may even decay and if infested by the root knot nematode, it will show galls. Effects of nematode activity are most apparent in hot weather; plants will recover poorly from the heat. If you find that your plants are infested with nematodes, add compost to the soil, which will attract beneficial fungi that will then attack the nematodes. Or, you can drench the soil with fish emulsion, which repels or kills nematodes. |
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Slugs, Snails Slugs are ugly. They are snails without shells. Plants attacked by slugs and snails suffer large ragged holes in their leaves, fruit and stems. You may also see the slimy trails left by the creatures on the leaves or on the soil around your plants. Slugs begin feeding at the bottom of the plants and work their way up. They first attack plants that have been damaged in some way, but they will eat anything. The best control is to set up a barrier to keep them off of vulnerable plants or out of the garden. Handpicking will work if you begin early in the season, but a number of different traps also provide effective control, and by using them you won't have to handle these grotesque little creatures. Slug bar trap. These commercial traps are small rectangular boxes that you fill with beer or slug poison and place in the garden. They are covered so the rain does not dilute the beer. A Shallow dish, such as a pie plate fill it with beer and place it in the yard. Sink the pan into the soil so the slugs have easy access to the trap. Replace the beer every few days or after a rain. Some gardeners report that 1 tsp baking yeast in 3 ounces water is even more effective than beer. Slugs and snails are especially fond of hostas. |
Thrips The flower thrips, Frankliniella tritici (Fitch). These are the most abundant and widely distributed thrips in the U.S. Adults are yellow and orange and about 1/20 inch long. Their feeding produces necrotic spots or blotches on flower petals and rough callous tissue on leaves. They feed primarily on various grasses, wild flowers, clover and citrus blossoms, then migrate to flowering woody plants. To aid in detecting thrips, place a sheet of white typing paper beneath the leaves or flowers and shake the plant. The thrips will fall onto the paper and can be more easily observed and identified than when on the plant. Also look for the small spots of varnish-like excrement on the leaves. If plants are flowering, be sure to inspect the flower parts for thrips presence.Since thrips are so small, use a 10 to 15-power magnifying glass. Blue-colored sticky traps have been developed for monitoring thrips and are available commercially. They appear to be somewhat more effective than yellow traps. Since thrips may come in large flights over an extended period of time, insecticides which give good initial results but have a short residual effect are generally inadequate for control of thrips infestations. Systemics are highly effective and provide long-term control. Select insecticides that have the least effect upon other non-target organisms.. |
Whitefly These pests are tiny, mothlike, white, winged insects. When shaken from a plant, they look like flying dandruff. The yellowish nymphs are legless, flat and oval, and may resemble scale insects at certain stages. Whiteflies suck the juices from plant leaves, buds and stems causing serious weakening of the entire plant. The leaves turn yellow and die and the growth of the plant will be stunted. Spray infested plants with insecticidal soap as soon as you spot the problem. Apply it every two to three days for two weeks. For very serious infestations, you may have to resort to pyrethrum, but try the soap spray first. If they don't detract from your landscape design, consider planting chives or onions in and around plants vulnerable to whitefly attack. Gardeners often recommend nasturtiums and savory as companion plants, but no studies have shown these plants to be effective repellents. |
Fungus gnats Adults are small (1/8 inch long), fragile grayish to black flies with long, slender legs and thread-like antennae. Their wings are clear or smoky-colored with no pattern and few distinct veins. Larvae are clear to creamy-white and can grow to about 1/4 inch long. They have shiny black head capsules.Damage: Life cycle: Inspect plants carefully before purchase for signs of insect infestation. Always use sterile potting soil to prevent introduction of fungus gnats. Overwatering, water leaks and poor drainage may result in buildup of fungus gnats. Allowing the soil to dry as much as possible, without injury to the plants, is effective in killing many maggots. Houseplants taken outside during warm weather may become infested with insects before being brought back indoors. Inspect plants carefully and discard if heavily infested and unable to save. Remove all old plant material and debris in and around the home. Practice good sanitation. Electrocutor-light fly traps will attract and kill many adults at night. Use yellow sticky cards (traps) for adult fungus gnat detection. Place traps just above the plants at a frequency of one per 500 to 1,000 square feet. Replace when covered with insects. Check traps 2 to 3 times each week Adult fungus gnats are killed easily with pyrethrins spray or aerosols labelled for "gnats" or "flying insects." Repeat applications several times if necessary. Commercial mushroom growers may get control with diazinon, methoxychlor or naled (Dibrom), whereas commercial greenhouse growers can use Bacillus Thuringiensis Berliner var. israelensis (Gnatrol, Vectobac). Licensed pesticide applicators can apply a restricted use pesticide, namely oxamyl (Vydate). Always read the label and follow directions and safety precautions.
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