DUSTING AND SPRAYIXfi CURCUUO AFTER HARVEST. 17 
The data given in Table 12 show that the mortality of confined 
curculios was greater on the plat that was dusted twice than on 
that sprayed once or on the untreated plat. Plat 1. untreated, 
showed a mortality of 7 per cent, plat 2, sprayed once, showed a 
mortality of 81 per cent, plat 3, sprayed twice, showed a mortality 
of 91 .67 per cent. This last percentage, however, should not be consid- 
ered in comparison with the others, as only 60 beetles could be 
obtained for the test on this plat, and, furthermore, two sprayings 
resulted in an almost complete defoliation. Plat 4, dusted twice, 
showed a mortality of 87 per cent. 
GENERAL SUMMARY. 
Post-harvest spraying and dusting decreased the number of beetles 
per plat. The chief benefit from this work, however, lies in prevent- 
ing the rapid increase of second-generation adults, which are emerging 
in numbers at that season of the year. The untreated plats show a 
marked increase in second-generation adults after harvest. 
In 1921 two post-harvest dustings decreased the number of beetles 
6 per cent, whereas on the check plat during the same period there 
was an increase of 69.53 per cent. In 1922 one post-harvest appli- 
cation of spray decreased the beetles 40.91 per cent and two dustings 
decreased the beetles 56 per cent, whereas during the same period 
there was an increase of 25 per cent on the check or untreated block. 
Mortality tests conducted in the insectary show that the dust is 
not effective after a period of two weeks. In 1921 there was a mor- 
tality of 98.89 per cent of the beetles confined from the plat that was 
dusted twice; a 65.56 per cent mortality from those collected from 
the plat dusted once, and only a 5.56 per cent mortality from those 
collected from the check or untreated plat. In 1922 there was a 
mortality of from 87 per cent to 91.67 per cent of the beetles confined 
from the plats that were dusted or sprayed twice, an 81 per cent 
mortality from those collected from the plat sprayed once, and only 
a 7 per cent mortality from those collected from the check or untreated 
plat. 
Two applications are necessary for best results in controlling the 
curculio after harvest, making the first four weeks after the harvest 
of the latest variety of peaches and the second two weeks later. 
Post-harvest treatments are not advisable except in cases where 
the curculio infestation has been severe during the peach season. 
Post-harvest liquid spraying after the usual liquid spray schedule 
had been followed earlier in the season on the fruit resulted in severe 
burning of the foliage. Two post-harvest applications of a 10 per 
cent arsenate of lead and 90 per cent hydrated lime dust can be used 
with safety, and are recommended in cases where the curculio has 
been bad. 
In dusting peach trees after harvest for the curculio this dust 
should be used at the rate of about one-fifth of a pound per tree. 
I When used at that rate the dust can be applied for about three- 
fourths of a cent per tree for each application. 
