190 THE PLUM CUECTJLIO. 
made 8 times, beginning June 9 and continuing until September 3. 
The two trees sprayed with Paris green at the rate of 1 pound to 50 
gallons of water showed a benefit in lessening curculio injury as com- 
pared with the unsprayed trees of about 50 per cent — more exactly, 
72.70 per cent of the fruit was uninjured as against 42.70 per cent 
uninjured on the unsprayed trees. The trees that had been sprayed 
with London purple gave 61 per cent sound fruit as against 62 per 
cent fruit from the unsprayed trees. In conclusion Prof. Forbes 
states: 
Furthermore, if we must judge from results thus far reached, these various appli- 
cations are all of too slight effect upon the apple for plum curculios to make them 
worth use against these insects, Paris green diminishing curculio blemishes less than 
one-half, London purple about one-fifth, and lime not far from one-fourth. 
No further experiments seem to have been made until 1900, at 
which time Prof. Stedman began an investigation of the curculio on 
apple, which was continued during 1901 and 1902, the results of 
which are given in the bulletin of the Missouri Agricultural Experi- 
ment Station No. 64, published in 1904. Experiments in spraying 
apples were made in three different orchards. It was desired to test 
the practicability of killing the beetles while they were feeding on 
the leaves before the appearance of the bloom. One-half of each 
orchard was sprayed twice from the time the leaves opened until 
the blossoms opened, leaving the other half as check. These exper- 
iments were repeated the following year, and in addition four appli- 
cations were given after the falling of the blossoms at intervals of 
10 days. By this means about 60 per cent of the fruit was protected 
in spite of reinfestation of the sprayed trees from the unsprayed 
part of the orchard. The desirability of spraying the entire orchard 
to prevent overflow was pointed out, as under these conditions the 
benefits would be very marked, and the great bulk of the " stings" 
would be prevented. 
In the report of the Illinois State Horticultural Society for 1902, 
page 158, Prof. E. S. Titus discusses the plum curculio under the 
caption "Insects other than the codling moth injurious to the fruit of 
apple," and gives results of observations made at the instance of 
Dr. Forbes. In regard to the use of arsenicals he says: 
The experiments tried in the Illinois entomologist's office several years ago showed 
very clearly that the curculio may be killed by spraying trees to which it resorts in 
early spring with Paris green or other arsenical poisons, as it feeds at that time largely 
on young leaves. Consequently, other things being equal, that orchard will be least 
infested and its fruit least injured whose trees are sprayed early in the spring, as for the 
codling moth or canker worm. On the whole, however, much the most promising 
and important measure is the prompt destruction of fallen apples to prevent the escape 
of the curculio larvaB into the earth, after which it is almost impossible for these 
larvae to go through their usual transformation. 
