weeks, so that it continues long after squares nave formed, the killing 

 of 30 per cent at the time squares begin to form means reall}^ but a 

 t'er}^ small percentage of the total number of hibernated weevils. Con- 

 tinuous use of poison throughout the season on the Government farms 

 has not shown any gain from the use of poison. The tests made by 

 individuals have, as a whole, failed, there being only one instance of 

 apparent success in contrast to the great number of admitted failures. 

 Even where apparently successful the results were mainly due to the 

 yield from improved seed being contrasted with that from native seed. 

 The greatest apparent success was in the field of Mr. W. Withers, 

 Lockhart, Tex., where the land was repeatedl}' broken prior to phmt- 

 ing, and King seed was planted early, followed by thorough cultivation. 

 This plat yielded immensel}^ superior results over other plats in which 

 the same variet}' of seed was planted later on land not so thoroughly 

 prepared. N^o instance could show more strihlngly the failure in. the 

 use of Paris green^ and at the same iimc emphasize more conclusively 

 the efficiency of the cultural method. 



SUMMARY. 



From the rather extensive observations and experiments noted on 

 the preceding pages the Bureau of Entomology concludes that the 

 use of Paris green in controlling the boll weevil is absolutely futile. 

 This conclusion is based upon the following determined facts: 



I. Persistent use of Paris green from the time of chopping until 

 picking (in some cases as many as 15 applications) has failed to mate- 

 rially reduce the numbers of the weevils or to increase the jield. 



II. Careful examination of verj^ manj- experiments with the poison 

 made bj" planters in Texas has failed to reveal conclusive instances of 

 its successful use. 



III. Reasons for the impossibility of poisoning weevils successfully 

 are to be found in the facts that only a very small percentage emerge 

 from hibernation before the squares are set upon the plants, that they 

 do not drink the dew on the leaves at night, and that as soon as squares 

 are set all feeding is done within the shelter of the bracts (shuck) 

 beyond the reach of any poison that might be applied. 



211 



