Historically, the tarnished plant bug has a reputation as a significant pest of commercial tree fruit production. They have also become pests of ornamental and forest tree nurseries as well. At least 385 host plants of the tarnished plant bug have been recorded, including weeds, vegetables, and flowers (Young, 1986). This insect is mainly an early season pest on tree and shrub hosts. The adult tarnished plant bug overwinters; overwintered adults tend to be darker in color than the summertime adults. In the early spring, when temperatures allow, the insects begin their feeding on swelling and opening buds. This feeding may kill the buds or force new budding which leads to an eventual bushy appearance to the tree or shrub. These insects may be preferentially attracted to hosts with multiple flushes of growth. Most of the feeding injury from the tarnished plant bug occurs from mid April to late June. Adult female tarnished plant bugs primarily lay their eggs in the stems and flowers of herbaceous plants; if on conifers, eggs are laid in flowers or blossoms. Eggs are tiny, approximately 1 mm long, and curved and typically deposited singly. Following egg hatch, the immature nymphs can disperse to new plants, but typically remain on the host plant on which the egg hatched to feed. Newly hatched nymphs are yellowish green and 1 mm long. As the nymphs mature, they develop yellow, green, and black spots. Fourth and fifth instar nymphs have 4 black spots on the thorax and 1 black spot on the abdomen. There are 5 nymphal instars. The youngest instars are wingless, and by the 5th instar the nymph is approximately 0.15-0.17 inches long with developing wing pads. Adults have fully developed wings, are ready flyers and disperse. Adult females may be slightly larger than adult males, ranging from 0.19-0.23 inches in length. Adults are yellowish to reddish brown in color with darker brown or black markings. Summertime adults can vary in color, from pale with few black markings to almost completely black with few pale yellow markings. Legs and antennae are relatively long. By mid summer, the life cycle (from egg to adult) can be completed in approximately 25 days (Johnson and Lyon, 1991). 2-5 generations may occur per year. By late summer, tarnished plant bug populations are often very abundant. Plant bug populations tend to be aggregated or in groups. The tarnished plant bug is native to the United States and Canada.
If tarnished plant bug feeding happens after shoot elongation begins, it is possible for host plant shoots to die and turn black. Sometimes shoot stunting or distortion occurs from feeding. On poplar seedlings, a specific type of damage from the tarnished plant bug occurs. This is from irritation to the plant by the stylet (mouthpart), cell content removal through feeding, as well as toxic components to the insect saliva. Feeding damage can occur on developing host plant buds and leaves; damaged buds may yield leaves that are ragged or discolored.
Traps may be available to aid with early spring monitoring of the tarnished plant bug. These may be particularly helpful in plant nurseries or other locations where hosts are susceptible to plant bug damage. Look for signs of early season damage to buds, leading to raggy leaves, brown or discolored leaf tissue, leaf crinkling, premature drop of buds, flowers, fruit, increased branching, or multiple crowns.
Removal of favored alternate host plants or weed species, particularly around ornamental plant nurseries, can help reduce the potential for pressure from the tarnished plant bug. Goldenrod, vetch, mullein, and dock are examples of weed species utilized by the tarnished plant bug.
Clancy and Pierce (1966) list known natural enemies of plant bugs in the genus Lygus, including the tarnished plant bug. They list: Anaphes ovijentatus (from specimens from New York), Polynema pratensiphagum (Ontario, Canada), Euphoriana uniformis (New York and New Jersey), Leiophron pallipes (New Jersey), Alophorella opaca (Canada), Phasia (Alophorella) aeneoventris (Wisconsin), Alophorella fumosa (New Jersey), Alophorella pulverea (Wisconsin), and an unidentified species in the Ichneumonidae (Canada). Canadian specimens also indicate that a species of nematode (Hexamermis spp.) may also feed on the tarnished plant bug. A biological control organism (an introduced Braconid wasp species, Peristenus digoneutis) is reported to have reduced New Jersey tarnished plant bug populations by 75% (Capinera, 2001).
Acephate (NL)
Acetamiprid (L)
Beauveria bassiana (NL)
Bifenthrin (NL)
Carbaryl (L)
Chlorpyrifos (N)
Chromobacterium subtsugae (NL)
Clothianidin (NL)
Cyantraniliprole (NL)
Cyfluthrin (NL)
Deltamethrin (L)
Dinotefuran (NL)
Flonicamid+cyclaniliprole (N)
Tau-fluvalinate (NL)
Gamma-cyhalothrin (L)
Horticultural oil (L)
Imidacloprid (L)
Insecticidal soap (NL)
Isaria (paecilomyces) fumosoroseus (NL)
Lambda-cyhalothrin (L)
Malathion (L)
Neem oil (NL)
Permethrin (L)
Spinetoram+sulfoxaflor (N)
Active ingredients that may be applied systemically include: acephate (injection), acetamiprid (injection), clothianidin (soil drench), cyantraniliprole (soil drench, soil injection), dinotefuran (soil drench), imidacloprid (soil drench), and neem oil (soil drench).
When used in a nursery setting, chlorpyrifos is for quarantine use only.
Make insecticide applications after bloom to protect pollinators. Applications at times of the day and temperatures when pollinators are less likely to be active can also reduce the risk of impacting their populations.
Note: Beginning July 1, 2022, neonicotinoid insecticides are classified as state restricted use for use on tree and shrub insect pests in Massachusetts. For more information, visit the MA Department of Agricultural Resources Pesticide Program.
