53 



previously recommended. With a limited number of rows, and these 

 swarming with Boll Worm moths, a tasteful and attractive sweet well 

 poisoned and thoroughly applied is of some value. A great difficulty 

 is met with in that the liquid applied dries after a short time and what- 

 ever moths are to be poisoned in this way must feed soon after the ap- 

 plication. This process makes a daily application necessary and of 

 course renders the crop as forage entirely useless. The worst feature 

 however, is that the poisoned sweet, in order to be an effective poison 

 must be made so strong that one thorough application burns the foliage 

 and checks the growth of the vines to such an extent that from that- 

 time the pea- vines become useless as a crop for attracting the moths. 

 Thus the very purpose for which it was planted is suddenly discon- 

 tinued. If the brood of moths found at this time issued evenly, this 

 might not be so serious an objection, but, since the brood issues very 

 scatteringly, it is desirable to have the trap a continuous one. 



Hence it appears that whatever of benefit is attained by the use of 

 this insecticide it is at too great a sacrifice to make the extensive appli- 

 cation of it advisable. 



Experience has shown that the poisoned liquid must be actually ap- 

 plied to the food-plant in order to be most attractive, and hence most 

 efficient. If placed in pans or plates or on posts, boards, and like ob- 

 jects, a few moths are trapped occasionally. These catches even seem 

 rather accidental, as the great majority are not attracted and, in fact, 

 the liquid offered in any other locality than upon choice food-plants 

 seems really to form no decisive attraction. 



PYRETHRUM. 



As already intimated, no insecticide can be of practical utility against 

 the Boll Worm. Much work has been done, however, in making decoc- 

 tions and various extracts of this powder. The principal points con- 

 sidered were those of determining the difference in extractibility of hot 

 and cold decoctions, hot and cold extracts with oils, such as kerosene 

 or head-light oil. These various extracts and decoctions were always 

 made into an emulsion with oil. The emulsions were then diluted and 

 applied in the usual way. There is some difference in the extent of 

 extraction of the insecticidal properties by hot and cold processes, as 

 also the aqueous and oil extracts. The difference by one of the proc- 

 esses is a decided one, though its practical utility upon this particular 

 species is questionable, except in special cases under certain conditions. 



LIGHTS. 



Numerous and decisive experiments with lamps for trapping Boll 

 Worm moths were made. Some of these were made under the most 

 favorable circumstances. They all proved the absolute folly of this 

 practice among planters. The moth is not attracted much at any stage 



