CONTROL OF PEACH DISEASES IN GEORGIA $ 
The life-history studies of the senior writer in 1921 and 1922 showed 
that in those seasons two full generations of the curculio occurred in 
Georgia, and a large percentage of the "worms" in the fruit har- 
vested late in the season in those years were larvae of the second 
brood. In 1923 there was only one generation of the insect in cen- 
tral Georgia, whereas in 1924 there was a partial second generation. 
Marked variation in the yearly life cycle of the curculio in Georgia 
is therefore evident, and may be ascribed to seasonal climatic con- 
ditions. 
Prior to 1921 the importance of the possible presence of a second 
generation of the curculio was not fully realized, and the schedules 
for spraying and dusting were formulated with control measures 
directed against only one brood of the insect. It had been an ac- 
cepted fact that for practical purposes the curculio produced only 
one well-defined generation annually (6, p. 20). Another reason for 
not recommending additional applications of spray lay in the desire 
to minimize the risk of injury from them. In view of the fact that 
recent studies have emphasized the possibility and importance of the 
occurrence in Georgia of two generations of the curculio in some years, 
and since the severe infestation of the curculio in 1920 did not manifest 
itself to any great extent until the late varieties of peaches were 
ready to be harvested, one would suspect the presence of two gene- 
rations in the season of 1920. The schedules for spraying and dust- 
ing in 1920 were based on a single brood of curculio per season, and 
a second brood would have no control measures directed against it. 
It is very probable that two broods of curculio larvae occurred in 
each of several seasons prior to 1920; that in each case the second 
brood was allowed to work unchecked, and that as a result its progeny 
appeared in uncontrollable numbers in 1920, when weather conditions 
were especially favorable for the development of the insect. It is 
also quite probable that after years of success in the control of the 
curculio and brown rot, growers had become rather careless in the 
conduct of spraying operations. 
In each of the four years the experiments in spraying and dusting 
were conducted on the Hiley and the Elberta, two of the varieties 
most commonly grown in Georgia. The relative abundance of the 
curculio in the Hiley orchards in these four seasons is very indicative 
of the gradual reduction of the general infestation in Georgia as a 
result of the vigorous campaign waged during the period for the sup- 
pression of the curculio. The Hiley variety is seldom attacked by 
the second-brood larva? of the curculio in years when there are two 
generations of the insect. As a consequence, the difference in the 
number of broods annually does not cause any considerable fluctua- 
tion in the yearly infestation of the Hileys. It is only in years when 
there is a heavy second generation of the curculio in a season char- 
acterized by late blossoming that second-brood larva? are found in 
the Hileys. 
Because of the tremendous curculio population left in the orchards 
in 1920, when Georgia experienced the heaviest infestation of the cur- 
culio in the history of the peach industry, the infestation was heavier 
in the season of 1921 than in the three seasons which followed. 
Assuming the infestation of 1921 to be 100 per cent, the relative 
abundance of the curculio in the Hiley experimental orchards for 
