2 BULLETIN 1374, U. S. DEPARTMENT OF AGRICULTURE 
inches. Cotton production is possible only by irrigation, and owing 
to lack of reservoirs the irrigation water which comes from the Nazas 
River must be put on the land whenever the water is available. 
As the greater part of the irrigation water usually arrives in the fall 
and winter, the general practice is to flood the fields (fig. 2) to a 
depth of from 1 to 3 feet at that time of the year. This often rep- 
resents all the water that the following year's crop receives except 
for what little rain may fall during the growing season. 
The work of 1921 and 1922 supplemented that of 1918 and 1919. 
As the life history and the habits of the pink bollworm under Laguna 
conditions were rather thoroughly studied in the previous research 
work, the greater amount of attention during the last two years was 
devoted to studies aimed more directly at control. 
Fig. 1.— Typical Laguna district scenery, showing character of country surrounding the valley 
DISTRIBUTION OF THE PINK BOLLWORM 
Since the report on the 1918 and 1919 work was published, new and 
important records of the occurrence of the pink bollworm in various 
parts of the world have been made. The species is. 'now known to 
occur in India, Palestine, Mesopotamia, Ceylon, Burma, Siam, 
Straits Settlements, China, Japan, Korea, the Philippine and 
Hawaiian Islands, East Africa, Zanzibar, Egypt, Sudan, West Africa 
(southern Nigeria, Angola, Sierra Leone) , Italian Somaliland, Brazil, 
West Indies, and Mexico, and in Texas, New Mexico, and Louisiana 
in the United States. 
The occurrence of the insect in the West Indies is of special interest. 
It was first reported from Montserrat and St. Kitts in November, 
1920. Later it was reported from Anguilla, St. Croix, and Porto 
Pico. In July, 1921, it was reported to occur throughout the Lee- 
ward and British Virgin Islands, but not south of Montserrat. 
In the United States, progress has been made in the eradication of the 
insect. There has been no recurrence of the two infestations in 
Louisiana for two vears. The infestation at Hearne, Tex., has not 
