PINK BOLLWORM OF COTTON IN MEXICO. 



29 



The damaged seed from the first pick weighed less per seed than from 

 the second pick, and the damage per seed from the first pick was 

 greater than in the second pick. This is probably because the bolls 

 from the first pick were attacked when they were greener and the 

 seeds were attacked when they were more immature than in the 

 other picks. There is no indication that the number of seeds per 

 boll is reduced on account of pink bollworm attack, as pointed out by 

 Gough. Unfortunately, the sample of the third pick is from a dif- 

 ferent plantation and is not quite comparable with the other samples. 

 It may be pointed out, however, that the average weight of the sound 

 seed in the second and third picks is almost the same and that the 

 loss in the individual attacked seed is greater in the third than in the 

 second pick. This is thought to be because a much larger number of 

 larvse had prepared to hibernate in the third pick and a hibernating 

 larva needs all the available space, especially in the single seed, 

 and had eaten out the kernels of the seed cleaner to prepare this space. 

 From the data given in Table XIII the loss in weight of the seed in 

 the different picks can be calculated, and this is summarized in Table 

 XIV. 



Table XIV. — Summary of table showing the loss in weight of the seed from the different 

 picks due to pink bollworm attack. 



Pick. 



Loss in 

 Actual i weight 

 weight i of in- 

 of seed fested 

 (grams). : seed 

 (grams). 



Corrected 

 weight 

 of seed 



(grams). 



Per cent 



of loss in 



infested 



seed. 



Per cent 



of total 



seed lost. 



Remarks. 



First 



261.45 : 8.42 

 278.78 ! 13.40 

 305.50 72.38 



269.88 

 292.18 

 377.88 



3.1 

 4.6 

 19.1 



1.24 

 1.84 

 3.82 



First pick=40 per cent crop. 

 Second pick=40 per cent crop. 

 Third pick=20 per cent crop. 





Third 





Total 









6.90 







1 









Table XIV shows a loss of 3.1 per cent in the weight of the seed 

 from the first pick, 4.6 per cent of the second pick, and 19.1 per cent 

 in the third pick. The data secured in 1919 showed that 40 per cent 

 of the crop was harvested in the first pick, 40 per cent in the second, 

 and 20 per cent in the third. The losses in the seed from the dif- 

 ferent picks when given their proportionate weights with respect to 

 the proportion of the total crop harvested in each pick show that 

 1.24 per cent of the total seed was lost in the first pick, 1.84 per cent 

 in the second pick, 3.82 per cent in the third pick, or that a total of 

 6.90 per cent by weight of the seed is lost due to the attacks of the 

 pink bollworm in the pickable cotton. 



When the above-mentioned field samples of seed cotton were 

 ginned the seed of the first, second, and third picks were placed in 

 separate piles. Using a 20-liter measure, an equal number of weigh- 



