large-scale experiments carried on during the winter of 1906-7. Three 

 large cages (50 bj^ 20 feet) were built over growing cotton at Dallas, 

 Calvert, and Victoria, in Texas. In different compartments of these 

 cages nearly 70,000 weevils were placed ; several thousand in each 

 compartment. After the weevils were placed inside, the plants were 

 removed from the first section about the middle of October. At regular 

 subsequent dates other sections were treated in exactly the same man- 

 ner. Consequently the results for each locality show exactly what a 

 farmer could have accomplished by the destruction of the plants at dif- 

 ferent times. The full results will be published in Bulletin 77, of this 

 Bureau, by Dr. W. E. Hinds and Mr. W. W. Yothers, who have had direct 

 charge of the work. In this connection it is necessary to call attention 

 to only a few features. 



In practically all cases the smallest survival of weevils was found in 

 those cages from which the plants were removed at the earliest dates, and 

 the number of survivors increased regularly as the dates of destruction 

 became later. For instance, at Dallas out of between two thousand and 

 three thousand weevils in each cage, only 2.5 per cent survived when 

 the plants were removed on October 13 ; 4 per cent survived destruction 

 of the food supply on October 16; 6.2 per cent survived destruction on 

 October 19; 12.2 per cent survived destruction on November 6, and 

 14.7 per cent survived destruction on November 12. These figures indi- 

 cate tJiat practically seven times as many iveevils survived after destruc- 

 tion of plants on November 12 as survived after a similar destruction 

 on October 13. This is a most striking illustration of the effect of 

 early destruction. 



In the cages at Dallas, Calvert, and Victoria, from which the plants 

 were removed in November, 14.26 per cent survived, while 4.41 per cent 

 survived removal of the plants in October — that is, the cutting off of 

 the food supply in November resulted in the survival of three times as 

 many weevils as survived when the work was done in October. These 

 figures are based upon averages of eight large cages at the three locali- 

 ties in which October destruction took place, as compared with seven 

 similar cages in which the plants were removed in November. 



TIME FOR DESTRUCTION OF THE PLANTS. 



It is naturally impossible to fix any date for the destruction of the 

 stalks which would apply to all localities and under all conditions. 

 The condition of the soil must be considered as well as the maturity of 

 the crop. While the condition of the soil can not be controlled, the 

 time of the maturity of the crop, except in extremely unfavorable sea- 

 son's, is largel.y within the power of the planter, since hy early planting 

 of early maturing varieties the entire crop may be matured before the 

 usual time of picking of the first cotton from native seed. Nevertheless, 

 Avhatever modifications are necessary in different localities and during 

 different seasons, the}' do not decrease the general strength of the 

 recommendations. 



The proper time for the destruction of the plants in the fall is when- 

 ever the weevils have become so numerous that there is no prospect 

 that any more cotton will be made. It will be an easy matter for any 

 planter to determine this point by an examination of a few plants in 

 his field. Whenever it is found that all, or nearly all, of the squares 

 and some of the bolls are being punctured, there is no hope for pro- 



