268 REPORT OF THE COMMISSIONER OF AGRICULTURE. 



wrong impression. For example, a planter informed tlie writer, in 

 re}>l.v to questions respecting" a certain field, tliat tlie worms tirst appeared 

 ill it t'nree days previous. It was a tield adjoining his residence, through 

 which he passed every day, and was one to which, as he iniormed me, he 

 had paid special attentiou. On visiting the field I found ir very badjy 

 infested with cotton-worms which were then two-thirds groun^ and hence 

 must have been much more than three days old. 



Although observers may fall into error respecting the time required 

 for the devastation of a field of cotton by this pest, exaggeration is 

 liaidly possible respecting the completeness of the destruction which 

 sometimes occurs. We have repeatedly seen places in which the plants 

 were so completely stripped of their foliage that there were not left as 

 many uneaten leases as there were stalks, a few dried and brown leaves 

 on the lower part of the plants being the only semblance of foliage left 

 on what, ten days previous, was a beautiful green field. In cases of 

 this kind, not only are all the green leaves eaten, but the' young bolls 

 are also destroyed, and often the bark is gnawed from the small branches. 



The stopping of the growth of the plant is not the only loss which the 

 destruction of the foliage entails. Open cotton is frequently injured by 

 the drojjping of the excrement of the larvae upon it. Much injury also 

 results from the premature opening of the bolls, caused by the destruc- 

 tion of the foliage. ISTot only is such cotton of inferior quality, but when, 

 in addition to the fully-developed bolls, many immature ones are made 

 to open, it is often impossible for the planters to pick the cotton before 

 much of it falls out upon the ground and is thus seriously damaged. 

 Immense losses sometimes occur in this way, when wind and rain closely 

 follow the destruction of the foliage by the worms. 



On the other hand, in some parts of the cotton belt — notaldy the more 

 northern se;('tions — the advent of the cotton- worm is not dreaded. It 

 rarely reaches these regions till late in the season, and then the planters 

 consider the destruction of tlie foliage a benefit rather than otherwise, 

 as in this way the maturity of young bolls, which would otherwise be 

 destroyed by frost, is hastened. Sometimes, even in southern portions 

 of the' cotton belt, in localities where tlie plant grows very raidv if the 

 worms do not ap|)ear early, the destruction of the leaves late in the sea- 

 son is regarded as a source of profit. 



No well authenticated instance is recorded of the cotton-worm feed- 

 ing u[)0u any plant excei)t cotton.* Many exjieiiments were tried to 

 iiuluce them to feed upon other plants, all resulting negatively. Even 

 when the larvae were placed u])on plants closely allied to cotton they 

 starved. Still there is reason to believe, as will be shown later, that 

 another food -plant exists in Wisconsin at least. 



When full grown, the larva folds one edge of a leaf over its body and 

 fastens it down with yellowish silk. (Plate VII, fig. 7.) It tlsen spins 

 a delicate cocoon about itself. At times, when the cotton-worms are 

 very numerous, it frequently occurs that the foliage is so badly eaten 

 that it is with difiiculty that the worms find a leaf in which to web up. 

 Their endeavors to conceal their bodies before pujiating aic at such 

 times very amusing. The merest fragment of a leaf is caMeil into service; 

 and frequently very vigorous struggles ensue between rivals endeavor- 

 ing to secure the same place. Often, too, the troulile of the successful 

 competitor does not end with his webbing up. Other larvae not yet 



*P. Winfiee, De Bow'a Review, iv, 251 (1847), eays: "In the West Indies they fet^d 

 pronnecuously on tfie leaves of a plaut there cal^^d the salve-bush ; this p)ant grows 

 aVioiit the height ami its leaves area good deal like i,lie mullein of this country, haviug 

 » whitish color aud a soft velvety feeliug. 



