14 
BULLETIN 139^, U. S. DEPARTMENT OF AGRICULTURE 
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 
unpickable. 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 1017 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 Mini blooms; of 343 normal blooms observed, 40.8 per 
cent dropped off without setting bolls; of an equal number of infested bolls 
<;7.<; 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 oil was unfavorably affected 
in both quantity and quality. 
(3) Loss in nonpickaWe cotton: 19.98 per cent of the entire crop was 
rendered unpickable. 
