Nov. io, 1913 
A Cotton Boll Weevil in Arizona 
95 
The altitude of Opelousas is 83 feet, of Victoria 145 feet, and of Tucson 
2,390 feet. The Arizona boll weevil is found at 4,000 feet altitude and 
higher. The highest altitude at which the Texas form has been found 
on cotton is under 2,000 feet. 
The maximum temperature at Opelousas and Victoria is 104° V., and at 
Tucson ii2°. The minimum temperature at Opelousas is 2 0 , at Victoria 
6°, at Tucson io°. The mean temperature at Opelousas is 67.3°, at Vic¬ 
toria 70°, at Tucson 68°. The average date of first killing frost in the 
fall for Opelousas is November 17; Victoria, December 10; and for 
Tucson, November 22. The average date of last killing frost in spring 
for Opelousas is March 5; for Victoria, February 20; and for Tucson, 
March 26. At Tucson, August is the only month in which the minimum 
temperature does not run below 56° F., which is the zero of effective 
temperature for Anthonomus grandis in Texas. At Victoria and Opelou¬ 
sas the minimum never goes below 56° in July or August. 
Of course, in the mountains where Anthonomus grandis thurberiae 
occurs the temperature does not reach quite as high a point as at Tucson, 
and the minimum temperature is lower. The chilly nights and warm 
days probably would 
retard the develop¬ 
ment and hibernation 
of the cotton boll 
weevil in the same 
manner if transplanted 
to Arizona mountain 
conditions. 
The points of great¬ 
est adaptation are evidently atmospheric pressure and humidity, and 
possibly high temperature, although typical individuals of Anthonomus 
grandis have been known to survive 114 0 F. at Dallas, Tex., while the 
excessive drought experienced for several years in northern Texas prac¬ 
tically exterminated the species. 
Cotton is cultivated in the Imperial Valley and the Colorado River 
valley in California, in the Salt River valley, the Gila River valley in 
eastern and central Arizona, and also in the Santa Cruz River valley of 
Arizona. 
The varieties grown are mainly long staple—Egyptian and Durango, 
with some Triumph. The crops, which are irrigated, are very promising 
and can be made with very little water if it is properly applied. 
The Arizona “wild cotton,” Thurberia, occurs in nearly every moun¬ 
tain range in southwestern Arizona where there is any moisture. In the 
vicinity of the Santa Cruz Valley cotton is grown within 5 miles of 
Thurberia plants growing in the mountains. The boll weevil was not 
found on the nearest Thurberia plants, nor were many of the nearest 
canyons investigated, but it was found to be abundant not more than 10 
miles distant. This is the first year of cotton in the Santa Cruz Valley, 
and it is expected that a large acreage will be planted in 1914. 
Fig. 9. —Anthonomus grandis , var. thurberiae; Wing. 
