282 REPORT OP THE COMMISSIONER OP AGRICULTURE. 



of the tlieory tliat warm winters are more apt to be followed by the worm 

 siuiply urge the idea that the severity of the colder winters kills the 

 hibernating individuals. 



The truth of the matter, as it seems to us, is that, other things being 

 equal, a warm winter is more favorable to hibernation than a cold one. 

 It seems to be true that the cotton-moth was originally a tropical or sub- 

 tropical insect, and that only in favored localities within the limits of the 

 United States can it hibernate at all. As we go northward the winters 

 become too severe for survival from one season to another. Farther 

 south, then, winters approaching to this northern severity must be un- 

 favorable, while winters approaching those of the normal habitat of the 

 moth will prove favorable. This is reasoning in the abstract. Actual 

 experience seems to show that occasionally the greatest worm-years 

 follow undoubtedly cold winters. This seems to have been the case with 

 the season of 1873, in some parts of Alabama at least. Such instances 

 we think, however, must be laid to a combination of other causes, work- 

 ing through a series of years; and that instead of the severity of the pre- 

 ceding winter having been the sole cause, the ravages of the worms 

 would have been even worse had a mild winter come before. 



Another and more important point concerning the inSuence of weather, 

 brought out by the 1878 circular, was, do the worms flourish most in a 

 wet or dry season ? In the answers to this question great unanimity 

 was found. With but few exceptions, the general opinion seems to be 

 that wet years are the most disastrous caterijillar-years. 



This fact (for such it undoubtedly is) has been always accounted for 

 by the fact that wet weather i)roduces a rank and succulent weed, of 

 superior nourishing power to one dwarfed and dried by continued 

 drought, and by the fact that in hot dry weather many worms are 

 actually killed by the heat of the sun and by the oven-like heat of the 

 earth when marching is attempted. 



Another point, intimately connected with this last, is the one that the 

 low, damp parts of a field are the ones where the worms always appear 

 first in spring. This may be accounted for by the probable fact that on 

 damp parts of a plantation the early cotton grows faster than on the 

 drier parts ; nectar is earlier secreted from the foliar glands ; the hiber- 

 nating moths are attracted by the nectar to that part of the field, and con- 

 sequently more eggs are there laid. 



Both of these facts haA^e, however, been accounted for by a plausible 

 theory, first publicly put forth by Mr. N. A. Davis, of Cherokee County, 

 Texas, in 1806 or 1807, and which is as follows : The ants which are so 

 numerous in cotton fields destroy many eggs, young larvae and pupae of 

 Aletia. These ants abound most in dry lands, hence in such localities 

 the worms are not permitted to multiply to so great an extent as in wet 

 lands. On the other hand, in wet seasons the ants are kept in check, 

 and consequently the worms multiply greatly. 



Mr. Davis draws the following practical conclusions : 



Let no wet lands be planted on Tvhicli tlie ant cannot live, nor let tlie liiglilands be 

 plowed while wet to destroy tho aut, and I am persuaded that the cotton crop will 

 never be destroyed by the worm again. The observance of these facts will do more 

 than all the poisons discovered and all the poison-distributers combined to protect 

 the planter in hia toil and guarantee him the rewardt; of his hands. 



Almost simultaneously with the letter from Mr. Davis in one extreme 

 of the cotton belt came a communication from Mr. J. C. Brown, of Willet, 

 Barnwell County, South Oarohlia, the other extreme, expressing almost 

 precisely the same views. Mr. Brown introduced this in his reply to the 



