As a rule insects don’t injure soybeans seriously, but damage has increased as the acreage has expended. Insects of soybean, i.e. velvetbean caterpillar, bean leaf beetle, and Mexican bean beetle. Velvetbean caterpillar is the larval form of the night-flying moth which attracts various legumes in Shoutheastern state. Velvetbean caterpillar attacks velvetbean, cowpeas, peanuts, kudzu, and other legumes, but this insect seems to prefer soybeans. The insect does not occur in the central and northern states. Velvetbean caterpillar can’t survive during the winter in the northern part of the United States, but this insect migrates northward from the warmer, southern areas each summer.
|source image: ento.okstate.edu|
The larvae or caterpillars are slender and black or occasionally greenish in color. Caterpillars are about 1 ½ inches long when mature, and caterpillars have a number of narrow, light stripes on their backs and sides. The worms or caterpillars eat the leaves, buds, and tender stems of plant, beginning at the top and working downward. The caterpillars work rapidly, and unless they are controlled they are capable of stripping the plant in a relatively short time.
How to control the velvetbean caterpillar?
Methoxychlor applied as a five per cent dust at the rate of twenty pounds per acre, can be used to effectively control this velveatbean caterpillar insect of soybean. A period of seven days should be allowed to elapse before forage treated with this chemical is harvested or fed to livestock.
The bean leaf beetle<$2Fdiv>
|source image: insects.about.com|
The bean leaf beetle attacks soybeans, garden peas, and cowpeas and occasionally it causes heavy damage in some areas. The beetle is similar in appearance to the spotted cucumber beetle, excepting that it is somewhat smaller, more yellow in color, and has slightly different markings. The mature beetle is reddish-yellow in color, about ¼ inch long, and its wings are edged in black with four black spots in the middle. During the larva or worm stage, the insect feeds on the roots, and later the beetles feed on the leaves.
How to control bean leaf beetle?
Parathion applied as a one per cent dust at the rate of 25 to 35 pounds per acre, is effective in the control of this insect. A period of fifteen days should be allowed to elapse before forage treated with this chemical is harvested or fed to livestock.
Mexican bean beetle
|source image: entnemdept.ufl.edu|
The Mexican bean beetle is yellow or copper colored. The Mexican bean beetle is about ¼ inc long and has 16 black spots on its back. The larvae are yellow colored, spiny, and about 1/3 of an inch long. Both the larvae and the adults feed on the leaves, but most damage is caused by the larvae. Various insecticides are effective per cent dust at the rate of 35 pounds per acre, or 25 per cent wettable powder at the rate of flour pounds per acre, (b) methoxychlor applied as five per cent dust at the rate of 35 pounds per acre or 50 per cent wettable powder at ther rate of three pounds per acre or (c) parathion applied as two per cent dust at the rate of 35 pounds per acre or 25 per cent wettable powder at the rate of two pounds per acre, are probably most satisfactory. A period of seven to ten days should be allowed to elapse before forage treated with malathion and methoxychlor are harvested or fed to livestock. The period for forage treated with parathion should be extended to fifteen days.