oe 
COTTON INSECTS 
reports results of an experiment "to determine the mortality of pink 
bollworm larvae in bolls buried 4 inches in soil, both dry and irrigated; 
bolls left on the surface of the soil, both dry and irrigated; and in bolls 
left on standing stalks. * * * On December 10, heavily infested cotton 
bolls were installed in screen cylinders for periodic winter and spring 
examinations. * * * An examination of one cylinder from each treatment, 
as well as bolls from one standing stalk on February 14, and again on 
February 28, showed that the heaviest kill had taken place in bolls buried 
4 inches and irrigated in December, and the next heaviest in the buried 
but not irrigated cylinder. In the remaining treatments there were but 
slight differences in mortality. Two loose larvae were recovered from 
the soil beneath the standing stalk. Mortality this year was less than 
in similar tests last year. * * * In the standing stalk treatment there 
was considerable difference, 89.1 percent kill in 1932 and only 49.5 per— 
cent in 1933. It will also be noted that thus far the mortality in bolls 
buried in December and not irrigated is higher this year than last." 
Pink bollworm overwinters in Mexico best in dry, unplowed land.—— 
C. S. Rude, Tlahualilo, Durango, Mex., reports that "Examinations to 
determine the overwintering larval population of the pink bollworm in a 
1,200-acre field of 'soca' cotton were started in January. The stalks in 
this field were cut, raked, and burned late in October. About one-third 
of the field was flooded in December and the rest left dry. Late in Janu— 
ary about half of the flooded portion was plowed, thus providing three 
types of treatment. It was found that in the dry unplowed land there was 
an average of 7.88 live larvae per square yard; in the flooded unplowed 
land an average of 2.66 live larvae per square yard; and in the flooded 
and plowed land an average of only 1.33 live larvae per square yard." 
Cultural control of pink bollworm.--D, A. Isler and A. J. Chapman, 
Presidio, Tex., have completed plant and soil examinations to determine 
reduction in worm population by clean-up. A summary of results shows 
"an average of 18,27 bollworms per square yard in fields examined be-— 
fore cleaning and 0.39 per square yard in fields examined after clean— 
ing, or an average reduction per square yard of 97.87 percent. * * * 
the percentage reduction in worm population by the cleaning plus natu- 
ral mortality on the 10 farms cleaned approximately between November 11 
and January 20 by the Bureau of Plant Quarantine ranged from 91.18 to 
100 percent. * * * The averages on a farm basis were 10.13 larvae per 
Square yard before cleaning and 0.247 per square yard after cleaning, a 
reduction of 96.86 per cent." 
Boll weevil activity halted by cold weather in February.--G. L. 
Smith, J. C. Clark, and A. L. Scales, Tallulah, La., reporting observa— 
tions on boll weevil hibernation, state that "In February a total of 50 
active weevils was recorded for the 70 cages, as compared with 154 for 
