Know Your Garden Bugs


Insects and mites can destroy or greatly reduce the yield potential of a number of our garden vegetables. These pests may damage the plants by eating the foliage, boring in stems or roots, sucking plant juices, or attacking the fruit. Control measures are often required to maintain good quality vegetables. These measures include good cultural practices and the safe and effective use of chemicals. 

Note: Follow label directions on the product you are using. Use only if crop, pest, or specific use is stated on the label.

Control of these pests can begin by using good quality seed or healthy seedlings. The quality of the plants should be maintained throughout the growing season. To do this, you should follow a sound fertilization program for your garden site. To help prevent pest buildup, you should destroy crop residue once the harvest is completed. This is especially true at the end of the growing season, because old plants can provide food for late feeding by pests and afford good overwintering sites. 


Chewing Insects

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Ants

Ants may be found in gardens for many reasons. They may feed on "honeydew" produced by aphids, feed on decaying fruit, or forage for other insects. They do very little, if any, damage to the plants and are largely a nuisance pest. The fire ant can be more than a nuisance because of its painful sting. Control aphids by spraying with one of the materials listed on the pesticide chart. Harvest vegetables on time and remove over-ripe vegetables from the garden area. Treat all fire ant mounds within 30 to 40 feet of the garden site with diazinon. 

Bean Leaf Beetle

Description. Coloration will vary, but adults are typically red to yellow with a black band around the margin of the wing covers. Black spots may or may not be present. 

Injury. Adult beetles often feed on the underside of the leaf, creating holes. If disturbed the beetles will drop to the ground and remain motionless for several minutes. 

Plants Attacked. All kinds of beans and peas. 

Blister Beetle

Description. These insects are long (3/4 inch) slender beetles. Their color patterns may vary from black, gray, or yellow and black striped. The yellow and black striped beetle is probably more common in our area. 

Injury. Blister beetles rarely do extensive damage in gardens. However, some years you will find many beetles feeding in large groups. During these periods, they may defoliate a number of garden plants. 

Plants Attacked. The insect will attack most garden crops, especially tomatoes. 

Cabbage Worm

Description. The larva of the cabbage looper is a slender green caterpillar with a thin white line located on each side. Its body tapers slightly toward the head. Adults are dull-colored moths. The female lays eggs in the night. The imported cabbage worm is leaf-green with a velvety appearance. Adults are white butterflies with three or four black spots located on the wings. They may be seen flitting around gardens during daylight hours. 

Injury. These two insects are often found on the same plant, and they damage the plant in the same manner. The outer leaves will be covered with large irregular shaped holes, along with damaged heads. Scheduled pesticide applications and good coverage, especially with the biological pesticides, are important in controlling these insects. 

Plants Attacked. Cabbage, collards, and related plants. 

Colorado Potato Beetle

Description. Adults are small, oval shaped insects with black and yellow stripes on the wing covers. The immature beetles are red with black spots. 

Injury. Both adults and immatures damage the plant by feeding on leaves and new growth. 

Plants Attacked. This insect prefers potatoes but will feed on eggplants, tomatoes, and peppers. 

Corn Earworm or Tomato Fruitworm

Description. The adult, a gray-brown moth, is most active during late evening and night hours and deposits eggs at this time. At the immature stage, the insect has a variety of color patterns that range from green or brown to a pink color with light colored stripes along the sides. This is the stage where the insect does the most damage. 

Injury and Control. In early season, this insect will feed in the whorl of young corn plants, giving the leaves a ragged appearance. They rarely cause significant damage during this period. Later, adult moths will deposit eggs on emerging silks and the larvae will burrow into the ear. The larvae feed on developing kernels near the tip of the ear. To prevent ear damage, you should begin spraying or dusting when young silks first appear. Apply the insecticide every three to four days until silks begin to dry. To protect bees, make applications in early morning or late afternoon. When eggs are deposited on tomato plants, the young worms will burrow into the tomatoes. Inspect tomatoes regularly and apply an insecticide when young worms first appear. 

Cowpea Curculio

Description. This insect is a small black beetle. The immatures are white legless grubs. 

Injury. Adults feed on young pods, and females deposit eggs in small holes eaten through the pods. The young grubs feed within the developing pods. 

Plant Attacked. Southern peas. 

Cucumber Beetle

Description. Two cucumber beetles may be a problem in Mississippi: the striped cucumber beetle (SCB) and the twelve-spotted cucumber (TSCB). The SCB is yellow and black striped, while the TSCB is yellow-green with 12 black spots on its back. 

Injury. Adults feed on leaves, stems, and fruit. The larvae bore into roots and stems below ground. The larva of the TSCB has proved so destructive to corn in some areas that it is known as the Southern Corn Rootworm. 

Plants Attacked. The SCB feeds on cantaloupe, cucumbers, squash, and watermelons. The TSCB feeds on beans, peas, and corn silks as well as the above mentioned plants. 

Cutworm

Description. The adults are dull-colored moths that are most active during the night. The immatures are dull gray, brown, or black and may be striped or spotted. They generally feed at night and remain hidden during the day. 

Injury. The immature or worm is the damaging stage of this insect. It will generally cut young plants in two right at the soil line, while other types will climb plants and feed on leaves and buds. Most damage occurs in early spring shortly after plants have emerged from the soil. Cutworms may be controlled by using a preplant application of an insecticide. Diazinon as a spray or granules can be used. For the spray, mix 6 ounces of diazinon (25 ) in 3 gallons of water and spray this mixture over 1,000 square feet before planting. Immediately work the soil to a depth of 2 to 3 inches. Diazinon granules (5 ) should be applied broadcast at the rate of 10-12 ounces per 500 square feet and mixed into the soil to a depth of 2 to 3 inches. 

Plants Attacked. Nearly all vegetables. 

Fall Armyworm

Description. The adult is a dull-colored, nightflying moth. It usually does not appear in our area until the first part of June. Larvae will vary in color from light tan or green to nearly black, with yellowish lines down their sides. 

Plants Attacked and Injury. The larvae feed primarily on corn but will, on occasion, feed on peas, tomatoes, and beans. They infest the whorls of corn and can be found 1 to 2 inches deep in the whorl. It is difficult to get insecticides to the target. Direct sprays into the whorls or use 4 to 7 ounces of diazinon (5 ) granules per 500 square feet. 

Flea Beetle

Description. These are very small beetles that jump vigorously when disturbed. The color patterns may vary from black to brown, and some may be striped. 

Injury. Damage by this insect is caused largely by the adult beetles when they eat small holes in the leaves. At times the damage is so extensive that leaves look like they have been peppered with fine shot. 

Plants Attacked. Flea beetles will feed on eggplant, tomatoes, peppers, cucumbers, potatoes, and sweet potatoes. 

Mexican Bean Beetle

Description. The adult varies from a yellow to copper color with 16 black spots on its back. The yellow, soft-bodied larvae have six rows of small black-tipped spines on their backs. 

Injury. Both the adults and larvae cause plant damage. They usually feed on the under surface of the leaf, rarely eating entirely through the leaf. As the damaged tissue dries, it breaks through, giving the leaf a lace-like, skeletonized appearance. 

Plants Attacked. All kinds of beans and southern peas. 

Pickleworm and Melonworm

Description. The adult in a moth that is somewhat wasp-like in appearance with a cluster of hairs located on the tip of the abdomen. The pickleworm larva is yellow green with numerous black spots. The melonworm is similar, but it lacks the black spots. 

Injury. The larvae do the most damage because they feed on foliage, leaf bud vines, and fruit, which causes the damaged fruit to sour and rot. The melonworm is more of a foliage feeder than the pickleworm. 

Plants Attacked. Cantaloupe, cucumber, and squash. 

Serpentine Leaf Miner

Description. The adult is a small fly, while the larva is a white maggot. 

Injury. The larvae feed between the upper and lower surfaces of the leaves. This feeding causes severe leaf damage that looks like slender, white, winding trails throughout the leaf. 

Plants Attacked. Beans, tomatoes, peas, and cucumbers. The most severe damage occurs with tomatoes. 

Squash Vine Borer

Description. The adult moth is very wasp-like in appearance and coloration. Eggs are glued one at a time on stems and leaf stalks, especially toward the base of the plant. The larvae are pale white and are about 1 inch long at maturity. 

Injury. The young larvae bore into leaf stalks and vines, causing them to wilt. If enough larvae are present, they will kill the plant. 

Plant Attacked. Squash. 

Tomato Hornworm

Description. The adults are very large moths with a 4- or 5-inch wingspan. The larvae are large green worms with white diagonal lines on each side and a prominent horn located toward the back. 

Injury. The larvae feed on leaves and may attack the fruit. 

Plants Attacked. Tomato, pepper, and eggplant. 

Vegetable Weevil

Description. Adult weevils are gray-brown with a light colored "V" on the wing covers. The larvae are cream-colored with a tinge of green and light yellow heads. 

Injury. The adults and larvae feed on leaves and roots of crops. 

Plants Attacked. Tomatoes, potatoes, spinach, cabbage, radishes, and turnips. 


Sucking Insects

Aphids

Description. These are small, soft-bodied insects with a wide color range varying from green to black. 

Injury. The aphids remove plant juices, causing the leaves to curl and turn yellow. They may cause a failure of bloom set in tomatoes. 

Plants Attacked. Aphids attack most vegetables, but they tend to cause more damage to peas, okra, mustard, cabbage, and turnips. 

Harlequin Cabbage Bug

Description. Adults are black, red, and yellow and shield-shaped. 

Injury. These insects (adults and nymphs) suck plant juices, causing the plant to wilt and die. 

Plants Attacked. Cabbage, collards, mustards, and turnips. May also feed on potatoes, tomatoes, and okra. 

Spider Mites

Description. These small, eight-legged creatures are light green to red and are barely visible to the naked eye. A fine web is often formed on the infested plants. 

Injury. Adults and immatures remove plant juices with small needle-like mouthparts. They feed primarily on the underside of the leaves and infest plants during hot, dry weather. We do not currently have a control for this pest. 

Plants Attacked. Beans, cucumbers, and tomatoes. 

Squash Bug

Description. This brownish-black insect is a large (5/8 inch) flat-backed bug. 

Injury. This insect can cause rather extensive damage due to its large size and large number of nymphs. It removes plant sap, causing the plants to blacken and die. 

Plants Attacked. All curcubits with a preference for squash and pumpkins. 

Stink Bug

Description. The adults are brown or green, shield-shaped bugs. They secrete a disagreeable odor when crushed. 

Injury. Adults and nymphs feed on developing fruit of peas, beans, tomatoes, and okra. They are usually mid- to late-season pests. 

Whitefly

Description. The adult has four wings with a yellowish body and looks like it has been dusted with a very fine white powder. 

Injury. Both immatures and adults damage the plant by withdrawing plant juices. 

Plants Attacked. Tomatoes, and okra.