Plant bugs

Plant bugs comprise a number of species, all "true bugs" in that they belong to the Order Hemiptera. Most are easily distinguished by the unpleasant protective odor they emit when threatened. Although some of these bugs are of minor importance for the home gardener, other species can cause serious injury when present in large numbers. The following potentially problematic species will be treated below in the order given: chinch bugs, harlequin bugs, squash bugs, stink bugs, and tarnished plant bugs. Both the nymphs and adults of these species damage their plant host by sucking its juices.

Chinch bugs are 1/16" long, black with white or brown fore wings, brown legs and brown antennae. They are found primarily in eastern North America. Nymphs are red with a white stripe across the back or black with white spots. The curved eggs from which they emerge range in color from white to dark red and are laid in the soil or on the roots. Chinch bugs adversely affect corn plants by feeding on the leaves and stalks.

Brightly colored harlequin bugs are 1/4" long, red, black, shiny and shield-shaped. They are mostly found in southern states. Nymphs are oval, red and black, and emerge from distinctive white and black striped, barrel shaped eggs laid in double rows on the undersides of leaves. Harlequin bugs attack cabbage and other crucifers including cauliflower, broccoli, turnip and radish. In addition, they occasionally feed on squash, sweet corn and garden beans. Their feeding produces white and yellow blotches on leaves, or results in leaf wilt and drop. Handpicking is an effective control for these pests, especially if you manage to get rid of the very first adults and their eggs as they appear. If the infestation is serious, spray affected plants with insecticidal soap laced with isopropyl alcohol, or dust with sabadilla. For recurring problems, spray vulnerable crops with insecticidal soap in early spring.

Squash bugs are 1/2" long, brown to black, and flat backed. They lay brown eggs in clusters on the undersides of leaves. Upon emerging, the nymphs proceed to feed in colonies, particularly on squash, pumpkins, cantaloupes, cucumbers and watermelons. Unfortunately, squash bugs are ungrateful guests, and poison the leaves of their hosts with toxic salivary juices, causing large, discolored areas to develop. Affected leaves may also wilt, curl and turn brown. If squash bugs manage to kill the vines that feed them, they may then attack the fruit. They do their worst damage in mid and late summer when nymphs are abundant. Control squash bugs by collecting and destroying adults and egg clusters by hand. Late in the season, try trapping them under pieces of board or burlap, where they will likely seek overnight shelter, and then destroy them by stepping on them.

As stated above, most plant bug species emit an unpleasant odor when disturbed, but the stink bug is the most foul smelling. Stink bugs are 1/2" long and shield shaped. They are primarily brown in the eastern U.S. and green in the southeast and west. Their favored hosts also vary from region to region: in the east, they include blackberry, cabbage, corn, peach and tomato; in the west, asparagus, bean, pea, and potato; and in the southeast, bean, citrus, peach, pecan, potato and tomato. The best preventive measure for the eastern brown stink bug is weed control. Serious infestations of southeastern and western green stink bugs can be controlled with sabadilla dust.

If the stink bug is the smelliest species of plant bugs, the tarnished plant bug is the most problematic for the home gardener. It is 1/4" long, oval, flat and brownish, mottled with yellow and black. It is highly mobile. It inserts its long, curved eggs into stems, tips and leaves. The emerging nymphs are pale yellow. The tarnished plant bug damages plants by injecting poison into young shoots, flowering buds and fruit while it punctures cells to suck juices. It also carries fire blight disease, to which several trees are vulnerable. Symptoms of infestation and resultant damage are black spots; pitting on stem tips, buds, and fruit; deformed roots; blackened terminal shoots, and ruined flowers. Fruit tree damage can be particularly serious, since the pest's feeding on developing buds early in the season can virtually halt fruit development and eliminate fruit production. Fruit damage later in the season usually appears as a dimple or a scab (peaches, pears and strawberries are especially vulnerable to this kind of damage). Control infestations of this pest with 3 applications of pyrethrum, applied at three day intervals during the early morning when the bugs are least active. Dust heavy infestations with sabadilla. Prevent damage to vulnerable crops with barriers such as fine netting or agricultural fleece. Prevent future infestations by cleaning up crop residue in the fall and destroying all bugs ready to overwinter there.

Other images

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Not all plant bugs are pests; this wheel bug (Hemiptera ) eats other insects
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Stippling on pepper leaf Capsicum) probably from the feeding of true bugs or leafhoppers (Hemiptera)
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Hatched eggs, probably from a true bug (Hemiptera), many of which lay barrel-shaped eggs
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Close-up of fourth instar of spined soldier bug (Hemiptera )
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Adult stilt bug (Hemiptera )
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Underside of adult stilt bug (Hemiptera )
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Stilt bug nymph (Hemiptera ) on squash leaf (Cucurbita)
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Plant bug (Hemiptera ) eggs in various stages of hatching
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Barrel-shaped eggs of plant bugs (Hemiptera ) have hinged lids which are thrown back when nymphs are ready to emerge
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Barrel-shaped eggs of plant bugs (Hemiptera ) have hinged lids which are thrown back when nymphs are ready to emerge; some have already emerged
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Barrel-shaped eggs of plant bugs (Hemiptera ) have hinged lids which are thrown back when nymphs are ready to emerge
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Plant bug (Hemiptera ) emerging from its egg
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Plant bug (Hemiptera ) nymph
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Plant bug (Hemiptera ) nymph on its back showing its long, piercing-sucking stylet
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Stunted and deformed leaflets on thornless honey locust (Gleditsia triacanthos) are characteristic of the feeding of certain plant bugs (Hemiptera ) and leafhoppers (Hemiptera)
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Close-up of stunted and deformed leaflets on thornless honey locust (Gleditsia triacanthos) probably caused by the feeding of certain plant bugs (Hemiptera ) or leafhoppers (Hemiptera)
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The stippling on this silver maple leaf (Acer saccharinum) was caused by some type of piercing-sucking insect; such as, a true bug (Hemiptera ) or a leaf hopper
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Stippling on silver maple leaves due to feeding by true bugs (Hemiptera ) or leafhoppers; galls, possibly maple bladder galls caused by an eriophyid mite, are also present
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Close-up of immature plant bug (Hemiptera )
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Stylet (mouth part) of immature plant bug (Hemiptera )
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Not all bugs damage plants; this assassin bug (Hemiptera ) eats other insects
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Leaf-footed plant bug (Hemiptera) laying eggs on a window screen