﻿14 BULLETIlSr 1397, U. S. DEPARTMENT OF AGEICULTURE 



bolls with the advance of the season, and indicate the possibility of 

 a severe reduction of yield, particularly in all late-maturing cottons 

 where the second and third pickings are important. Fortunately for 

 Egypt, one of the principal varieties of cotton grown there, the 

 Sakellarides, matures its crop early and yields most of its cotton with 

 the first picking. In spite of this favorable circumstance, however, 

 and of expensive control operations enforced by the Government, a 

 very conservative estimate by experts indicates that this insect causes 

 a loss of at least 17 per cent to the Egyptian crop. In the Hawaiian 

 Islands the pink bollworm has prevented the development of the 

 cotton industry, which at one time showed considerable promise. 



In Brazil, through correspondence with the governors of the 

 principal cotton-producing States of the Republic, the minister of 

 agriculture collected data for an estimate of the damage to the cotton 

 crop caused by the pink bollworm in 1917. The loss reported ranged 

 from 30 per cent of the crop in the State of Alagoas to two-thirds 

 of the crop, or 30,000 metric tons, in the State of Ceara. 



DAMAGE IN MEXICO 



Special effort has been made to ascertain the degree of damage which 

 the pink bollworm causes the cotton crop in the Laguna district of 

 Mexico. In making the estimates two plans have been followed, 

 one being to send experienced crop reporters to the Laguna, who 

 collected data according to the plans followed in estimating injury 

 to the crops from various causes in this country. Planters were 

 interviewed and the consensus of their opinion as to the actual 

 loss was determined. The other method consisted in estimating 

 the quantity of cotton left unpicked in the fields on account of the 

 injured bolls passed over by the pickers. In Mexico there are no 

 important causes other than the pink bollworm which render bolls 

 unj)ickable. The relation between the number of unpicked bolls 

 and the number picked, as shown by the burrs remaining on the 

 plants, has been taken in a general way to indicate the loss. This 

 method is only a rough approximation; its accuracy will vary from 

 year to year because, regardless of the degree of actual damage, 

 the fields will be picked more thoroughly in years when the price 

 is high than when it is low. 



The actual injury caused by the pink bollworm in 1917 was 

 investigated by a joint body representing the Mexican and American 

 commissions, which visited many plantations in the Laguna. It 

 reported that the loss to the crop of 1917 chargeable to the pink 

 bollworm was not less than 30 per cent. 



In 1919 a very special study of the various forms of injury was 

 made {14)- It was determined that the injury could be classified 

 approximately in the following manner : 



(1) Loss in squares and blooms; of 343 normal blooms observed, 40.8 per 

 cent dropped off without setting bolls ; of an equal number of infested bolls 

 67.6 per cent dropped off. An undetermined loss was also due to early shedding 

 of infested squares. 



(2) Loss in pickable cotton; the lint suffered deterioration in quality, the 

 seed was reduced 6.9 per cent in weight, and the oU was unfavorably affected 

 in both quantity and quality. 



(3) Loss in nonpickable cotton; 19.98 per cent of the entire crop was 

 rendered unpickable. 



