15 



I hat a very small percentage of weevils survive the winter. Consecinently, 

 in the fall it is i)()ssil)le to practice a strictly remedial step, namely, the 

 destruction of the plants in toto as soon as the possibility of obtaining any 

 more cotton becomes remote. Experiments have shown that a very high per- 

 centage of weevils which would hibernate to damage the crop during the next 

 season can be destroyed. Following this all-important step, the work of the 

 liureau of Entomology has shown the necessity of obtaining an early crop. 

 'J'he remarkable powers of reproduction of the pest allow such an increase 

 by the middle of sunnner that the progeny of a very few hibernated 

 individuals is sufficient to practically destroy all new fruit as it is set upon 

 the plants. The fall destruction of the plants can be practiced without 

 important nioditications in any (piarter. However, there are many modifica- 

 tions of the system of hastening the maturity of the crop that must be prac- 

 ticed in different regions, owing to diverse climatic and soil conditions. During 

 the season of 100-1 the Bureau has established a number of experimental 

 farms to ascertain definitely what these modifications nuist be. In Texas and 

 Louisiana at present there is a weevil-infested region of at least 0.000,000 

 acres of cotton lantl. This extends from Brownsville northward a distance 

 of 500 miles over very diversified soil formations, with their couse(]uent 

 diversity in phmtation ]»ractices. 



The extent of the infested territory, from west to east, is also in the neigh- 

 borhood of 500 miles. In this territory the rainfall varies from such a small 

 amount as to make irrigation absolutely necessary, in the west, to the Red 

 IJi^er in Louisiana, where the normal annual precipitation is in the neighlior- 

 liood of 00 inches. These two variations in soil, involving the essential farm 

 operations, and in rainfall, changing the development of the weevil very 

 considerably, are the factors that have made it necessary to establish experi- 

 mental farms at a number of points. Fifteen of these farms have been in 

 operation. In most cases in the neighborhood of 100 acres is devoted to each 

 one. In the aggregate about 1,800 acres are involved. Although the work on 

 these farms is strictly experimental, they have an incidental value as demon- 

 stration farms. From the experimental standpoint it has been necessary to 

 evolve a careful system of checks. Conseijuently, whenever a plat is planted 

 with the seed of a certain variety, or with certain fertilizers, or cultivated in 

 some certain way, one alongside of it is treated in all respects according to the 

 ordinary methods^ in vogue among the planters of the locality. It is fortunate 

 for the performance of such work that the boll weevil moves about but little 

 in the fields until at least as late as midsummer. Were this not the case, it 

 would be necessary to have the plats far removed from one another. How- 

 ever, sufficient separation is brought about by simply planting a few rows of 

 sorghum or some similar crop between the different plats. The actual weevil 

 conditions in each plat are detei'mined by careful observations each week or 

 ten days. Early in the season the number of adult weevils per plant is 

 estimated by the examination of a fixed number in the plats. Later, when the 

 truit is being daniiiged, the exact status is determined by the figuring of the 

 percentage of infested fruit on groups of ten or more plants in three different 

 locations in a plat. Of course the j-ield of cotton is important, but from an 

 entomological standpoint the tables showing percentages of infestation are the 

 exact indication of the effects of the work. 



All this field work is carried on under an original system, which relieves the 

 Bureau of the trouble and expense of running the land and working the crop, 

 but at the same time gives it absofute charge of as much area of cotton land 

 as it is desired to utilize for experiments. Contracts are entered into with 



