Aphids are common garden pests. They are small, pear-shaped insects recognized by their “cornicles” which resemble dual tailpipes. These tiny creatures are represented by hundreds of species and almost as many colors. Although aphid damage is most noticeable on fruit and shade trees, and ornamentals, they also infest flower and vegetable gardens. You will find aphid colonies on the undersides of leaves and the tips of branches or new growth.
Do you see a clear, shiny sap on the top of the lower leaves on your plants? Many aphid species produce large amounts of honeydew, a sweet and sticky sap. The honeydew will accumulate on anything found under infested trees or plants (such as your car!). Because of its sweetness, the honeydew will attract other pests such as ants, flies and wasps. Eliminating the aphids can often help aid the management of problem ants.
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Aphids damage plants by sucking the sap from the leaves, twigs, stems or roots. They sometimes transmit plant diseases in the process. Leaves attacked by aphids have spotty yellow discolorations, usually on the undersides; the leaves may later dry out and wilt or curl. Some species of aphids form galls – swellings of plant tissues that are globular or spindle-shaped. The galls, which often turn brown, contain many aphids in all stages of development.
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Egg clusters are usually deposited on the underside of leaves. Females normally deposit 200-500 eggs during their lifetime. Eggs hatch in 3-6 days during warm weather. Early instar larvae are gregarious, feeding as a group and skeletonizing leaves. Larvae are primarily, if not entirely, foliage feeders but can attack the fruit, feeding mainly on the surface. Normally, larvae develop through 6 instars in 14-20 days. Larvae reach a maximum size of about 35 mm. Pupation occurs in the soil and the pupal stage generally lasts 11-18 days. Total generation time is about one month.
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At first, feeding by small army worms is not very noticeable or damaging. After a couple of weeks of growth, the larger caterpillars feed voraciously as they march across turf areas, eating all above ground green leaf tissue and leaving behind large areas of thatch and brown turf. After feeding for 2 to 3 weeks, the caterpillars dig into the top inch of the soil to pupate. Within 2 weeks, a new population of moths emerges and usually flies several miles before laying eggs to start the cycle all over again. It is possible in some years to have as many as 4 generations of fall armyworm in Georgia.
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Bagworm caterpillars make distinctive 1.5 to 2 inch long spindle-shaped bags that can be seen hanging from twigs of a variety of trees and shrubs. Sometimes the bags are mistaken for pine cones or other plant structures.
Bagworms prefer juniper, arborvitae, spruce, pine, and cedar but also attack deciduous trees. Female moths cannot fly but the larvae can disperse. Very small caterpillars can spin strands of silk and be carried by wind, an activity called “ballooning”. Larger larvae may crawl to adjacent plants. |
Bagworms pass the winter as eggs (300 or more) inside bags that served as cocoons for last year’s females. The eggs hatch in mid- to late April or May in most moderate temperate zones and the tiny larvae crawl out to feed. Each uses silk and bits of plant material to make a small bag that protects and camouflages it as during feeding and growth.
If only a few small trees or shrubs are infested, handpicking and destroying attached bags may provide satisfactory control. This must be done effective during fall, winter or early spring before the eggs hatch. |
The adult chinch bug is about 3 to 5 mm (1/8 to 1/5 inch) in length and black with white markings on the wings.
Chinch Bugs have piercing-sucking mouthparts and they feed on the sap of grass plants. They reside in the thatch area of the turfgrass, and prefer to feed on the lower leaf sheath and crown area of the plant. The chinch bug can be a major insect pest on home lawns throughout the country. The chinch bug inserts its straw-like mouthparts into the plant tissue and sucks out the plant juices while injecting chemicals into the plant which clog the vascular system. The area around the feeding puncture usually turns yellow. Damaged areas first appear as small, irregular patches which enlarge as the insects spread. Chinch bugs are most damaging in open, sunny areas. |
Chinch bug damage also can be difficult to distinguish from that caused by drought. Detection of significant numbers of the insects themselves is the best proof that chinch bugs are the cause of the damage.
Examine the grass in the marginal areas of injured patches, not in the clearly dead grass. Spread the grass gently with your fingers and look in the thatch, near the soil surface. Chinch bugs are usually very active in the summer, so you will be able to see them scurrying around, especially on warm summer days. Chinch bugs are found most readily in the weakened, yellowing grass around a dead spot in the lawn. |
Emerald ash borer (EAB), Agrilus planipennis Fairmaire, is an exotic beetle that was discovered in southeastern Michigan near Detroit in the summer of 2002. The adult beetles nibble on ash foliage but cause little damage. The larvae (the immature stage) feed on the inner bark of ash trees, disrupting the tree’s ability to transport water and nutrients.
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Prevention is the key in ensuring your trees will not succumb to the emerald ash borer. Insecticides that can effectively control with systemic insecticides that are applied as soil injections or drenches.
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White grubs are the larvae of many species of beetles, mainly belonging to one family- the scarabs. This may include the May/June Beetle, the European Chafer, the Masked Chafer, the Japanese Beetle, or the Oriental Beetle.
Larvae or grubs are all similar in appearance. Fully grown they are about ½” to ¾” long, white to grayish, with brown heads and six distinct legs. They usually assume a C-shaped position in the soil. |
Early stages of grub damage appear mainly in the late summer or early fall when the grass begins to wilt. Watering does not make the stress go away, and because the grubs have decimated the roots, damaged turf can be picked or even rolled up with little effort. The turf will also feel spongy underneath. In addition to doing their own damage, grubs are an excellent food source for several animals, and these predators will harm the lawn as well while they are feeding. Since grub damage often goes undetected until the turf is rolled up by hungry predators, it is often too late to save the lawn from severe destruction.
Grubs feeds on the turfgrass roots. They chew the roots off close to the surface, preventing the grass from obtaining water and food. When the conditions are hot and dry, the damage from grubs is more apparent as the plant cannot recover. Damage during wet periods or from small infestations on healthy lawns can sometimes go unnoticed. |
The name “leaf miners” is a catchall term for certain moth, beetle and fly larvae that tunnel between the upper and lower surfaces of leaves. They usually feed inside the leaf. Developing mines will show up as tiny translucent spots of lighter green color than the rest of the leaf. The larvae tunnel through the leaf forming blotches and discoloration. As the miners move to the outer edge of the leaf, the leaf turns brown. The larvae finish feeding in late June or early July and then fall to the ground where they pupate. There are at least two generations per year.
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Timely spraying for the first generation of leaf miners and larvae will help prevent greater numbers in any later generations.
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There are thousands of species of mites. Some of the most common mites include Chiggers, bird mites, clover mites, dust mites, or spider mites.
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Serious infestations can kill plants. You can spot a bad infestation when you see webbing on the underside of the leaves, especially on the lower branches. Mites tend to pick on certain single bushes - one plant can be infested but the bush next to it can show no signs at all.
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Adults are small, yellowish and have hair-fringed wings that are usually held across the back. Immature thrips are similar to adults but are wingless. Adult female thrips insert eggs into plant tissues. Just before hatching, the egg “squeezes” out of the tissue and hatches. Development progresses through two larval stages (instars), a pre-pupal non-feeding stage that crawls down into the soil, and a pupal resting stage from which adults emerge. Development from egg to adult takes 8 to 20 days depending on temperature.
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A great number of thrips are plant feeders. Both larvae and adults feed on flowers, leaves, twigs, or buds, using their piercing-sucking mouthparts, causing structural abnormalities of foliage in the form of leaf malformation (distorted, dwarfed, and matted), leaf fold, leaf roll, leaf blisters, and sometimes defoliation; causing discoloration of petals, deformation, or scarring of flowers.
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White grubs are the larvae of many species of beetles, mainly belonging to one family- the scarabs. This may include the May/June Beetle, the European Chafer, the Masked Chafer, the Japanese Beetle, or the Oriental Beetle.
Larvae or grubs are all similar in appearance. Fully grown they are about ½” to ¾” long, white to grayish, with brown heads and six distinct legs. They usually assume a C-shaped position in the soil. |
Early stages of grub damage appear mainly in the late summer or early fall when the grass begins to wilt. Watering does not make the stress go away, and because the grubs have decimated the roots, damaged turf can be picked or even rolled up with little effort. The turf will also feel spongy underneath. In addition to doing their own damage, grubs are an excellent food source for several animals, and these predators will harm the lawn as well while they are feeding. Since grub damage often goes undetected until the turf is rolled up by hungry predators, it is often too late to save the lawn from severe destruction.
Grubs feeds on the turfgrass roots. They chew the roots off close to the surface, preventing the grass from obtaining water and food. When the conditions are hot and dry, the damage from grubs is more apparent as the plant cannot recover. Damage during wet periods or from small infestations on healthy lawns can sometimes go unnoticed. |
Adult whiteflies look like tiny white moths, but are more closely related to scale insects. Most are about 1/16 inch long and have four wings. The wings and body are covered with a fine white powdery wax. Reliable identifications are based on the adults.
Spiraling whiteflies produce a waxy, hair-like, flocculent material on the undersides of leaves, lending them a white, fuzzy appearance.
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Whiteflies are tiny, sap-sucking insects that are frequently abundant in vegetable and ornamental plantings. They excrete sticky honeydew and cause yellowing or death of leaves. Whiteflies suck phloem sap. Large populations can cause leaves to turn yellow, appear dry, or fall off plants. Like aphids, whiteflies excrete honeydew, so leaves may be sticky or covered with black sooty mold.
When leaves are heavily infested with the spiraling whitefly , leaves may be yellow and wrinkled and and have conspicuous deposits of black sooty mold on leaf surfaces.
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