38 PAPERS ON THE COTTON BOLL WEEVIL^ ETC. 



Mall}' that 10 per cent of the squares were punctured upon cotton 

 which had been squaring for 5 weeks. At the end of the second 

 month of square formation there is an increase of from ten to fifteen 

 times in the percentage of punctured squares. On August 13, 1903, 

 an average of 35 per cent of the squares on our plats were punctured, 

 and on August 25 on Smith & Carson's plantation there were 42 per 

 cent. On August 13, on the experiment station plat at the College 

 barn, there were 66 per cent, these representing the injur}^ done upon 

 the emergence of the third brood of weevils. On Jul}" 11, 1901:, 

 Eckol's and Aj^er's cotton had 57 and 11: per cent punctured, this 

 being about 2 months after the first squares formed. In a general 

 wa}", it seems safe to say that usually 50 per cent of the squares will 

 be punctured by about 2 months after the cotton commences to square, 

 at which time, as we have seen, there would normally be about 100 

 squares to the stalk. With the appearance of the third brood of wee- 

 vils earlv in August the percentage of injury rises rapidly, and by 

 September 1 from 85 to 90 percent of the squares will be found punc- 

 tured, tho it is rather unusual to find over 90 per cent of the squares 

 punctured in this section when they are carefulh" counted. In 1901, 

 at the end of 6 weeks of square formation, there were but 8 per cent 

 of the squares punctured along the Brazos River, tho on the oldest 

 cotton, which had been squaring about 2 months, where the weevils 

 were thickest, 40 per cent were punctured. When one-half of the 

 squares are punctured it may be readily concluded that there are 

 probabl}' sufiicient weevils present to prevent an}" more squares from 

 forming fruit. It will be seen, therefore, that the critical period in 

 the relation betw-een natural increase of squares on the plant and the 

 increased injury by the boll weevil is during the period of 6 to 8 weeks 

 after first squaring, which usually coincides more or less closely 

 with the time between the appearance of the second and third broods 

 of weevils. Thus, if we consider 6 weeks as the average time 

 required for cotton to begin to square after planting, it will be seen 

 that the bulk of the fruit must be set in 85 or 90 days after planting. 

 In other words, it may be readily seen that to escape injury by the 

 boll weevil cotton must be so grown that the bolls will commence to 

 open in about 100 days after planting, and that all the fruit which 

 will probably be secured must be set within 45 days after the squares 

 begin to form. The advantage of early planted cotton and rapid 

 maturing varieties becomes, therefore, very apparent. 



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