PINK BOLLWORM

A, Cotton-bollworm rosetted by feeding of the pink bollworm. Green cotton with the boll sectioned: a. Eggs laid inside the calyx of cotton boll; b, entrance hole made by newly hatched larva (invisible to naked eye); c, larvae in cotton seed: d, hole in partition made by a larva traveling from one lock to another; e, exit holes of larvae. C. Mature larva. D. Pupa. E. Adult. F, Damaged open boll. (A, B, F, twice natural size; D and E, three and one-half times natural size; C. five times natural size.)

PINK BOLLWORM

The pink bollworm is a serious pest of cotton in many parts of the world. It was first discovered in the United States in Texas in 1917. In 1951 it was present in 6 of the 20 cotton-growing States Arizona, New Mexico, Texas, Oklahoma, Louisiana, and Florida. Infestations in Georgia have been eradicated.

The small pinkish caterpillars eat out the seeds of the cotton plant and thus reduce the yield, weight, vitality, and oil content of the seeds. They also reduce the quantity and quality of the lint. Severe infestations cause squares and small bolls to shed. The female lays 100 to 200 tiny eggs. The young caterpillar bores into a square or boll, where it feeds 10 to 14 days. When full-grown, it cuts a round hole through the boll and either changes to a pupa within the boll or drops to the ground to pupate. Development from egg to adult takes 25 to 30 days in midsummer. There may be as many as four to six generations a year in sections with long growing seasons. Larvae that develop late in the season may pass the winter in seed, old bolls, trash in the fields or at the gins, and in cracks in the soil.

Control: Methods of controlling the pink bollworm include destruction of cotton stalks immediately after the harvest; heat treatment of cottonseed; burning of gin waste; compression of lint; and the application as a dust or spray of 1.5 to 2 pounds of technical DDT per acre. In southern Texas, pink bollworm infestations early in any season are in proportion to the number of insects that survive the period between crops. The longer this period the fewer insects will survive. Therefore the number of overwintering insects may be reduced by destroying cotton stalks at the earliest possible date. The best procedure is to cut the stalks with a stalk cutter, which crushes them to the ground. If this operation is carried out early enough, a high mortality of pink bollworms results from exposure to heat of the sun. The roots should be plowed out promptly and the crop debris plowed under. All seedlings or sprouted cotton plants developing after the plowing should be eliminated before fruiting so as to create a long host-free period between crops. For best results these cultural practices should be carried out on an area-wide basis with the cooperation of all cotton growers. Cultural practices used to control the pink bollworm will also control the boll weevil.

In regions where temperatures of 10 F. or lower are expected during the winter the stalks should be left standing.

If you find an insect resembling the pink bollworm in areas thought to be free of it, you will help in the ceaseless fight against it if you place it in a bottle of diluted alcohol and send it to the Bureau of Entomology and Plant Quarantine, Washington 25, D. C., with full information as to date and place of collection and your name.