6 BULLETIN 1482, U. S. DEPT. OF AGRICULTURE 
in the spring, and when weather conditions are favorable for pupation 
during May, June, and July, two generations of the insect will usually 
occur. The pupation of the insect is greatly facilitated by damp soil 
and high temperatures; the precipitation in May and July, 1921, 
was greater than normal, and the temperature for June was higher 
than normal. Two generations of the insect occurred in 1921, as a 
result of these conditions. The abnormal precipitation for July, 
1921, more than 10 inches, is reflected in the very heavy infection of 
brown rot in the experimental orchard of Elberta peaches. 
In 1922 there were again two generations of the curculio in central 
Georgia, and it may be seen from Table 2 and Figure 2 that the tem- 
perature in February of that year was considerably above normal. 
In this region a warm February has a tendency to bring the curculio 
out of hibernation earlier than usual, even though the temperature 
is normal during March, the month when a majority of the beetles 
appear. In May and June the precipitation was much greater than 
4 S (5 7 
Fig. 1. — Comparison of normal monthly precipitation and temperature at Marshall- 
ville, Ga., for 29 years, with precipitation and mean temperature by months for 
the year 1921. Points indicating normal data are connected by a solid line; those 
indicating data for 1921 by a broken line 
normal, tending to hasten the development of first-generation adults 
in time to produce a second generation. The heavy precipitation for 
May and June is reflected in the scab infection of 1922. There was 
also a moderate infection of brown rot in the same year. 
In 1923 there was but one generation of the curculio. A cool, wet 
spring so prolongs the hibernation of adult curculios that they do 
not have sufficient time to produce a second generation before 'the 
peach crop is harvested. Figure 3 and Table 2 show a precipitation 
much above the normal for the first half of that year. Temperatures 
were about normal. The heavy precipitation in May is reflected in 
the heavy scab infections in 1923 in the experimental orchards of 
Hiley and Elberta peaches. 
A small second generation of the curculio occurred in 1924. 
Weather conditions during the period when the insects usually leave 
hibernation were not very favorable for their early appearance in 
