COTTON-INSECTS. The most important of the insects injurious to the American cotton culture is the cotton-worm, the larva of a noc tuid moth (Alctia xylina), which sometimes de foliates whole districts. It is believed to be South American, and first became strikingly harmful in the Southern States in 1804. It is now known all over the Union, but its Northern food-plant is unknown. A Government commis sion reported in 1871) that the average loss to the cotton-growing States due to its ravages was then from $15,000,000 to $20,000,000 annually. The moth is inches in spread of wings, the fore wings and body reddish brown, with delicate zigzag markings, and the hinder wings pale gray brown. It Hies at night, and deposits eggs singly or sparsely on the under side of the leaves of the cotton-plant, where they hatch in midsum mer in about 50 to 60 hours. The caterpillars begin at once to devour the leaves, and so many are they. sometimes, that whole fields have been defoliated in three days, when the caterpillars swarm elsewhere in search of more food. In mid summer the caterpillars remain about thirteen days, then fold a leaf about themselves and spill a cocoon in which they inmate. In two to four days after issuing from the chrysalis the female moth begins to lay—her average product being 400 eggs in the season. The natural food is the juice exuding from the glands on the leaf's midrib and at the base of blooms and bolls; but it will feed on any kind of fruit as it ripens. Until the worms are numerous enough to riddle the leaves badly, the moths continue to lay near their birthplace; then they migrate to consider able distances—seldom, however, until after the third generation of W01111A, ear July I, in south ern Texas. Migrations are most common in the fall months, the moths flying at night and on cloudy days. In the Southern States only the moths hibernate ( the worms never, nor any where), hibernation being more frequent in the Southwestern than in the Atlantic States. The moths hibernate under bark, in logs and timbers, etc., and mild winters are more severe on them than cold ones, which keep them torpid.
hi some districts there are a. many as seven generations in a season. The average time from the egg of one generation to that of the next is a mouth.
sap from the bolls by its puncture, causing them to become diminutive or abortive: but the prin cipal injury it does is by voiding an exerementi tious liquid which stains the cotton fibre yellow The caterpillars visit earliest low alluvial lands where the plants are luxurious and thrifty.
Moisture is favorable to their development, hot, dry weather unfavorable. The damages to the crop may reach 23 per cent. in the southern dis tricts: but in the no•t-hern the worms may do more good than harm, by removing superabun dant leaves, thus facilitating the ripening of the For further and extensive information, and preventive measures, Comstock, "Re port on Cotton Insects," in U. S. Dept. of Agri culture (Washington, 1879), illustrated; Riley, U. S. B-ntomological Commission, 4th Report (Washington, 1SS5) ; Bulletin \'o. 1S, New Series (Washington, IS9S).
The bud-wo•m is scarcely second in its evil effects. (See BoLL-Woam.) It is hatched from eggs deposited singly on all parts of the plant, taking only three to five days to hatch in summer. The worm is much like the cotton caterpillar. but larger. Its principal food is the flowers and bolls. The chrysalis is found a few inches underground. The chrysalis state lasts seven to ten days in midsummer, double that in cooler weather. The moth is in appearance and habits much like the Aletia, but seldom appears before July or August. Hibernation is in the chrysalis state only, and underground. Breeding continues until cold weather; but the first three generations of each year generally feed in the cornfields, the first lot seen on cotton being the fourth brood.
Other injurious moths infesting cotton and eating the foliage include the yellow bear (Spilo soma Virginica), the in (Saturnia /o), the I:et-worm or bag-worm (q.v.) , and several others. Cotton-culture in Egypt is afflicted by two very similar insects, viz., Prodenia littoralis and Ea rias insulana.
The cotton-stainer, nr redbug (DyRdereng -rellus). is a small suetorial bug, "which drains the or reddish, and very much depreciates its value in the market, the stains being indelible." It is also troublesome to orange-grmvers in cotton growing districts. See Insect Life, vol. i. (Washington, ISSS), illustrated. Several plant bugs, such as the capsid (Psallu.s delicatus), known in Texas as the cotton-flea. and certain small beetles, are also injurious to cotton. For a description of the weevil, see WEEVIL.
The natural enemies of toe cotton-worm and of the boll-worm are domestic fowls, births, spi ders, beetles, warps, ants, parasites, etc. As pre ventive measures, the free use of poisons is good for both, and fall plowing, which upturns the ehrysalids of the boll-worm, exposes these to the attacks of fowls and the fatal influences of cold.