File:Insects affecting the cotton plant (1897) (14781579815).jpg

Identifier: CAT87201480 (find matches)
Title: Insects affecting the cotton plant
Year: 1897 (1890s)
Authors: Howard, L. O.
Subjects: Cotton Diseases and pests
Publisher: Washington : U.S. Dept. of Agriculture
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ch in from two days to a week. The larva.—When first hatched, the bollworm looks much like thecotton worm. It is rather darker in color, but also walks like a looper,or measuring worm. It feeds at first near the eggshell, and then beginsto wander away, crawling from one leaf to another, until a young budor boll is found, into which it bores. Frequently several days pass inthis search for a boll, and rarely the worm may reach full growth upona diet of leaves. It is during this early, wandering, leaf-feeding exist-ence that the insect may be destroyed by arsenical poisons, as is true ofthe cotton worm. When the young worm enters the flower bud the invo-lucre flares open and the young bud or young boll finally drops. Thisshedding of cotton is, however, not caused by the bollworm alone.Other insects are concerned in the damage, and the flaring and droppingoccasionally occurs when no insect injury can be found. A very con-siderable amount of damage may be done in this way, as a single 11
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Fig, 6. Traiisforniations of cotton bollworm: 1. Egg on under side of cotton leaf; 2. Larva one-third grown boring into square; 3. Entrance hole of young larva in square, with excremental pellets at edge of_hole;4. Kearly full-grown larva just issued from boll; 5. Full-grown larva on leafstem; 6. Pupa shown incenter of underground earthen cell; cell shown in longitudinal section; 7. Adult moth, light varietyt8. Adult moth with dark fore wings; 9, Adult moth in resting position, wings slightly elevated. 12 young larva will travel from bud to bud, deserting each before it falls.The bud pierced just before opening is forced into premature bloom,but the worm usually feeds upon the stamens and pistil, rendering itincapable of fructifying. As the bollworms grow, they begin to varygreatly in general appearance. Full-grown worms may be found ofalmost every intermediate stage of color between light green and darkbrown or rose. They may be unstriped and unspotted, or they maypossess dark stripe