Distribution. Redheaded flea beetle is distributed widely in the eastern United States and Canada. Although it has been collected in Montana, it is rarely found west of Manitoba, Kansas, and eastern Texas.
Smartweed flea beetle occupies a similar range. It is distributed widely in the eastern states and provinces, but is found only as far west as South Dakota, Colorado, and New Mexico.
Host Plants. The adults of both redheaded and smartweed flea beetle have been observed to feed on various vegetables, including bean, beet, cabbage, corn, eggplant, lettuce, okra, parsley, potato, and sweet potato. Other crops such as alfalfa, apple, clover, cranberry, currant, gooseberry, grape, horseradish, raspberry, soybean, sugarbeet, sunflower, strawberry, and numerous woody ornamental shrubs are also attacked. As might be expected of insects with such a wide host range, numerous weed hosts have been reported, including smartweed, Polygonum pensylvanicum; lamb-squarters, Chenopodium album; giant ragweed, Ambrosia trifida; plantain, Plantago major; beggartick, Bidens frondosa; redroot pigweed, Amaranthus retroflexus; Canada lettuce, Lactuca canadensis; Canada thistle,
Cirsium arvense; and giant foxtail, Setaria faberii. Of the aforementioned weeds, the first four are thought to be preferred by redheaded flea beetle. Redheaded flea beetle larvae have been observed developing on corn, and both species attack sugarbeet.
Life Cycle and Description. Apparently, there is only a single generation per year. Adults are present from mid-summer until winter. Eggs are present at all times except spring. The biology of smartweed flea beetle is almost unknown. Following is a description of redheaded flea beetle.
The adults of smartweed flea beetle are distinguished from redheaded flea beetle only by the lack of an orange-red head. In all other respects, they are virtually identical (Smith, 1970). Further study may demonstrate that smartweed flea beetle is merely a color variant of redheaded flea beetle.
The biology of redheaded flea beetle is not well studied. Hawley (1922), Smith (1970), and Jacques and Peters (1971) provided the most complete information on life history.
Adult redheaded flea beetle.
Adult redheaded flea beetle.
The adults feed on the epidermis of foliage, usually the upper surface. They create elongate holes, often leaving the lower epidermis intact as a transparent membrane. They may aggregate on certain plants, and often prefer weeds to crops. Jacques and Peters (1971) noted that the adults were abundant on corn only in the absence of preferred weeds. Corn silks were observed to be preferred over leaf tissue, and beetles were observed to leave corn ields after silks were mature. Hawley (1922) noted that bean plants usually recovered from defoliation; the exception was during dry weather, when permanent damage or death could occur.
The larvae feed on, and burrow within, plant roots. Jacques and Peters (1971) found redheaded flea beetle larvae interspersed with corn rootworm larvae among corn roots in Iowa, but flea beetle larvae were much less numerous, and less damaging than northern corn rootworm. Riley (1983) documented severe damage to germinating soybean seeds and seedlings by redheaded flea beetle in Mississippi. The larvae scored the seed surface, and burrowed through the seed, stem, and roots.
Weed management is a key to effective management of both redheaded flea beetle and smartweed flea beetle, as these insects consistently are reported as pests only where favored weeds are abundant. Chemical treatments applied for corn rootworm larvae are adequate for redheaded flea beetle larvae, though seldom needed. Adult damage is easily prevented with foliar applications of insecticide if the crop is carefully monitored.
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