18 RELATION OF DROUGHT TO WEEVIL RESISTANCE IN COTTON. 



It is easy to understand that a variet}^ with a rapid-fruiting habit 

 like the Mexican cotton would be even more likely to have definitely 

 determinate growth than an early-flowering variety like the Kekchi. 

 The small size of the jolants of early varieties may be ascribed to the 

 fact that vegetative growth is less rapid after fruiting commences 

 and if dry weather ensues an extra early variety may mature and 

 cease to grow even under the same conditions that permit another 

 variety with later fruiting habits to continue its development. 

 Determinate habits of growth, like other desirable things, may be 

 carried to excess. If selection for earliness be directed solely to the 

 question of early flowering or early opening of bolls the effect on yield 

 may be adverse. Very early flowering or very early opening of some 

 of the bolls is not in itself a guarantee of the prjrctical weevil- 

 resisting value of a variety. Varieties that flower very early may 

 develop more slowly or attain a precocious maturity if exposed to 

 dry weather or to other unfavorable conditions that interrupt the 

 growth of the plants. 



IMPORTANCE OF DRY WEATHER IN HUMID REGIONS. 



In cooler and more humid regions the importance of the drought 

 factor must of necessity decline. Unless the weather is hot and dry 

 enough to interfere with the propagation of the weevil larva?, the 

 direct advantage secured from drought in a dry climate is not 

 obtained. A humid climate with heavy dews may allow unimpeded 

 develo])ment of weevils, even in the absence of rain. Yet there is a' 

 very important indirect advantage in a period of dry weather, even 

 though the conditions are not severe enough to destroy the weevils. 

 Too much moisture interferes with the development of the cotton 

 plant, either by stunting its growth or by causing the shedding of 

 buds and young bolls. In a district where there are no weevils such 

 a shedding may do little damage, for the plants continue to produce 

 buds and can soon replace the loss, but with the weevils present the 

 loss of the early crop by shedding becomes a much more serious 

 matter. 



In a continuously humid climate the early buds must be expected 

 to furnish the crop, for all the later buds are likely to be destroyed 

 by the weevils. There must be no delay in the development of the 

 cotton if a crop is to be set before the insects become destructively 

 numerous. The closer the race becomes between the cotton and the 

 weevils, the more important it is that the plants lose no time in 

 development and that the crop receive no setback by the shedding of 

 buds or bolls. Every precaution that favors the quickest possible 

 development becomes Avorthy of careful consideration, such as the 

 planting of the cotton in dry. well-drained soil, thorough preparation 

 and cultivation, and the application of fertilizers. 



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