80 EEPORT UPON COTTON INSECTS. 



worms sooner than they can find them otherwise is very strong evidence 

 of the lack of proper knowledge of the habits of this species. 



Many planters believe that the cotton- worm will only eat the cotton 

 after it has reached a certain stage of maturity. They have been led to 

 this conclusion chiefly owing to the fact that the early broods of the 

 worm consist of so few individuals that they usually escape observa- 

 tion. Other facts which have led to this belief are not so easily ex- 

 plained. It is sometimes observed that certain cotton-plants are left 

 untouched while other and older cotton growing near is entirely de- 

 stroyed. An instance of this came under my personal observation. In 

 a field where the cotton- worms were very abundant and had destroyed 

 two-thirds of the foliage, I observed that along a ditch through this field 

 the cotton was green and very little eaten. On inquiry, I learned that 

 this cotton had been planted a month later than that in the remainder 

 of the field, as the cotton first planted along the sides of the ditch had been 

 washed away. It may be that the nectar glands, which will be dis- 

 cussed later, were not soj^tive on the younger plants as on the older 

 ones 5 and hence the moffis, not being attracted to these plants, did not 

 oviposit on them. It should be noted, however, that when this obser- 

 vation was made (August 20) the younger plants were as large as those 

 planted earlier in the season ; and I can see no reason why the nectar 

 glands on these should not have been as active as those on the older 

 plants. Had facts which were discovered later in the season been 

 known at that time, this point would probably have been cleared up. 



It has been often remarked that the worms will not eat cotton which 

 is affected with rust. The reason usually assigned is that the leaves 

 are not suitable food. Although, doubtless, larvae would not thrive so 

 so well on such plants, is it not probable that less eggs are laid upon 

 them owing to the small amount of nectar secreted by them ? 



Although, as a rule, the cotton-worm feeds only on the leaves of the 

 cotton plant, it is occasionally found lying within the open flowers feed- 

 ing upon the stamens. It also frequently destroys the buds and small 

 bolls. This is the case when the plant is stripped of its foliage. I have 

 also seen many buds and bolls destroyed when the foliage on the lower 

 third of the plants was eaten but little. When a cotton- worm destroys 

 a boll, it does not, like the boll- worm, merely eat out its contents, but 

 often eats the greater part of the pod also. 



From what has been learned respecting the time required for the full 

 development of the larva, and the small amount of injury done during 

 its early stages, it can be seen that the accounts which are often heard 

 respecting the short time which elapses from the first appearance of the 

 worms to the complete destruction of the crop are founded on an error. 

 We have heard many accounts of instances where fields had been 

 attacked by cotton- worms and destroyed within three days! If by 

 "first appearance" one understands the earliest time at which a brood 

 of cotton-worms has been developed of sufficient size, both as to indi- 



