COTTON FLEAHOPPER

Cotton fleahopper damage:. a, blasted square; b, whiplike plant and lack of fruit resulting from blasted' squares; c, injured leaf. (a and c, natural size; b, about one-fourth natural size; adult and nymph, 15 times natural size.)

COTTON FLEAHOPPER

The cotton fleahopper infests cotton throughout the Cotton Belt. It causes the greatest damage in Texas, Oklahoma, and Louisiana, but in some years losses are also serious in other States. This pest often becomes sufficiently numerous on cotton to cause almost complete loss of the crop.

The cotton fleahopper lays eggs in the fall in the stems of croton (goatweed), other weeds, and to some extent in cotton. The eggs hatch early in the spring, and the population builds up rapidly on certain tender weeds, such as horsemint, croton, and evening primrose. The movement to cotton increases as the weed hosts become tough. Rainfall is favorable to the breeding on cotton, which continues as long as the plants are succulent. When the squaring season is over, the leafhoppers return to weeds to feed and to lay their eggs. A generation of fleahoppers spans 2 to 3 weeks.

The winged adults and the wingless young fleahoppers alike are very active and are hard to see. Both stages feed on the juices of the tender parts of the cotton plants, especially the terminal buds and small squares. The leaves become deformed and somewhat ragged in appearance, but the greatest damage is caused to the small squares. Many of the squares are killed when they are no larger than a pinhead; they turn brown or black and fall from the plants. Because they are so small they are frequently overlooked; the failure of the plants to bloom is sometimes attributed to weather or other unfavorable conditions. The infested plants grow taller and more whiplike; they have fewer large branches than normal plants and usually produce only a few bolls near the tops.

Control: If cotton is not squaring properly, or if young cotton fails to set small squares, the terminal buds should be examined for fleahoppers. Dusting should be started when 15 to 25 fleahoppers are found per 100 terminal buds.

The cotton fleahopper can be controlled by any one of the following dusts: DDT 5 percent; toxaphene 10 percent; dieldrin 1.5 percent; aldrin 2.5 percent; benzene hexachloride (gamma isomer 1 percent); chlordane 2 percent. When spider mites are likely to be a problem, 40 percent or more of sulfur or a suitable miticide should be added to organic insecticide formulations. Less effective control of the cotton fleahopper may be obtained with sulfur alone or with a 1 : 1 or 2: 1 mixture of calcium arsenate and sulfur.

Any of the following materials applied as low-gallonage sprays at the rates indicated per acre will give good control of the cotton fleahopper: 0.5 pound of DDT; 1 pound of toxaphene; 0.5 pound of toxaphene plus 0.25 pound of DDT; 0.1 pound of dieldrin; 0.2 pound of aldrin; 0.5 pint of 40 percent tetraethyl pyrophosphate.

Sometimes cotton aphids develop after the use of DDT dust or spray.