THE BOLL WORM— REMEDIES. 381 



through the fields to systematically kill all the worms, the effect upon 

 the cotton crop will certainly be noticeable. 



Poisoning. — Since the introduction of arsenical poisons for the Cot- 

 ton Worm the wish that the Boll Worm could be reached by them has 

 many times been expressed; but, working in the interior of the boll as it 

 does, it seemed impregnable to a shower of poisoned spray or dust. A 

 more careful study of the life habits of these worms, however, has shown, 

 as we have already stated, that the young worms feed for a longer or 

 shorter space of time upon the leaf or involucre upon which they were 

 born before seeking to penetrate a boll. It is also true that the larger, 

 even the nearly full-grown worms, in migrating from boll to boll, feed 

 occasionally upon the leaves, and it has been shown that the Boll Worm 

 is as susceptible to the influence of these poisons as is the Cotton Worm. 

 These facts can be easily demonstrated by examining the worms killed in 

 a carefully poisoned field. Many Boll Worms, large and small, will be 

 found among them. Moreover, a boll which has a slight coating of 

 some arsenical mixture is perfectly protected from the worm, if we can 

 believe the statement in the following extract from Professor Stelle^s 

 report : 



At the time of the season when the Boll Worm was most actively at work, I mad© 

 an experiment looking to a decision as to whether or not sprinkling the plants with 

 London purple had any bad effect upon that insect after it had ceased to feed upon 

 the leaves. Selecting several heavily fruited plants, I spread dry London purple 

 carefully over the bolls, applying it thinly with a camel's hair brush. It protected 

 every boll. While a large per centum of the bolls on all the neighboring plants were 

 afterwards bored into, not one to which I had applied the London purple was dam- 

 aged in the least. 



The poisoning for the Cotton Worm, then, undoubtedly accomplishes 

 two ends, in also destroying many Boll Worms. In regions where the 

 latter is especially injurious it may be thought worth while to poison 

 for it alone. In such cases the corn should be carefully watched and 

 the poisoning should be done in one or two weeks after the full-grown 

 worms are seen in bulk in the hardening ears — say, about August 1 in 

 Central Mississippi and Alabama. In these localities the poisoning for 

 the third brood of the Cotton Worm can be done at the same time. 



Pyretheum. — But, after all, no one of the remedies so far given is 

 absolutely satisfactory in itself. The more promising ones — fall plow- 

 ing, trap-lanterns, and poisoning — should all be used. The great desid- 

 eratum is something which shall reach and destroy the worms in the 

 bolls. This pyrethrum seems to promise, if we can judge from the ex- 

 periment which we had made by Professor Jones and Judge Johnson, 

 and which the latter has detailed as follows : 



Direct applications of poisons to them must be diflScult. All the feeders on the ex- 

 ternal parts of plants succumb to Paris green or London purple. There are none that 

 may not be reached by Pyrethrum in some form. 



And this last proposition, from experiments made this fall in company with Pro- 

 fessor Jones, or with some of his extracts, I have reason to believe will hold good. 



