Distribution. Rapid plant bug occurs in the United States and Canada principally east of the Great Plains. In western North America it is replaced by superb plant bug, but the two species overlap in the Rocky Mountain region and Great Plains. Both species are native, and there is some thought that they are variants of the same species (Slater and Baranowski, 1978).
Host Plants. These insects are known principally as pests of alfalfa and sweet clover, where they can attain high levels of abundance. Sometimes they move to vegetables, including bean, carrot, celery, and potato. They are also known from field crops such as cotton and sugarbeet, and such weeds as Canada thistle, Cirsium arvense; dock, Rumex sp.; and yarrow, Achillea sp.
Natural Enemies. The little is known about the natural enemies of these insects. In Ontario, the parasitoid Peristenus pallipes (Curtis) (Hymenoptera: Braconidae) was recovered from up to 60% of first generation rapid plant bug nymphs but none from the second generation (Loan, 1965). Some general predators such as the assassin bug Sinea diadema (Fabricius) and the ambush bug, Phymata fasciata (Grey) were thought to affect rapid plant bug in Alberta (Lilly and Hobbs, 1956).
Description and Life Cycle. There are two generations per year in northern areas of the United States. In Canada, there are two generations in southern regions, but only one further north. Overwintering occurs in the egg stage. In Minnesota, eggs of rapid plant bug hatch in May, and by mid-June first generation adults are numerous. Nymphs of the second generation are present in early July, and adults by early August. The second generation adults were observed to deposit eggs in August and September which overwintered. In Utah, superb plant bug exhibits a very similar phenology (Sorenson and Cutler, 1954). In contrast, in a single generation per year population in Alberta, first instars were most abundant in late May, instars 2-3 in mid-June, instars 4-5 in July, and adults from late July-September. Any surviving nymphs and adults die with the onset of winter. The time required for a complete generation is estimated about 55 days under warm conditions.
The biology of rapid plant bug was described by Hughes (1943), and nymphal morphology was provided by Webster and Stoner (1914). The biology of superb plant bug was given by Sorenson and Cutler (1954) and Lilly and Hobbs (1956).
These plant bugs are rarely considered to be significant pests, as they do not normally colonize vegetable crop plants. Damage usually occurs when the bugs disperse from a favored crop or weeds, often due to senescence or harvest. Adelphocoris plant bugs inflict damage on seeds and young tissue in much the same manner as Lygus spp. (see section on tarnished plant bugs and pale legume bug).
Because these plant bugs are not often a pest, insec-ticidal control is rarely warranted. Foliar sprays are effective, if necessary. Effective management of alfalfa can do much to alleviate problems with these plant bugs. As they overwinter in alfalfa stems, close cropping of alfalfa in the autumn and feeding the hay to livestock reduces the overwintering population. Burning of stubble in the spring is sometimes recommended, but this practice also destroys predator populations (Lilly and Hobbs, 1962).
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