June, ’23 
snapp: plum curculio 
275 
grams AS2O3. To reduce this to arsenate of lead we must multiply by 
3.509 1 which gives .000521 grams arsenate of lead to the calyx cup. 
It is evident therefore that in our regular spray work we place on an 
average sufficient arsenate of lead in each calyx cup to poison even a 
full grown larva of the codling moth should it eat all of it. Such being 
the case then each calyx cup properly hit with the spray will receive 
enough poison to prevent the entrance of first, second or even third 
instar larvae. 
Conclusions 
These experiments show that: 
1. In thorough orchard spraying a killing dosage of arsenate of lead 
for young apple worms is placed in the calyx cup. 
2. A coarse spray under high pressure is not essential. 
3. The spray gun with high pressure is effective. 
4. The plats showing the greatest average calyx content had low tho 
not the very lowest calyx infestation at picking time. 
President J. G. Sanders: The next paper is by Mr. O. I. Snapp. 
RECENT DEVELOPMENTS IN PLUM CURCULIO 
INVESTIGATIONS IN GEORGIA 
Oliver I. Snapp, Entomologist, U. S. Bureau of Entomology, Fort Valley, Georgia 
Abstract 
The establishment of the occurrence in the latitude of Central Georgia of two 
generations annually of the plum curculio, Conotrachelus nenuphar, and that a laige 
percentage of the larvae injuring the best late varieties of peaches are larvae of the 
second generation were the most important truths revealed as a result of extensive 
investigations started in 1921. They followed the most severe outbreak of the plum 
curculio that has ever occurred in the South, when Georgia peach growers lost 
several million dollars from curculio damage. A third generation was carried through 
in the insectary in 1922. Picking up and destroying the small peaches that fell 
several weeks after the pollination season assisted greatly in correcting Georgia’s 
abnormal curculio conditions, and is a wise supplementary control measure in latitudes 
where there are two generations of the insect. In one orchard a net saving of $5.25 
per acre resulted from the operation. Discing to break up the pupal cells in the 
soil and burning over hibernating quarters during the winter months are other supple¬ 
mentary conti ol measures that were successfully utilized. The investigations show 
that the ideal spraying or dusting schedule for the control of the plum curculio on 
peach in latitudes where there are two generations, consists of four treatments of 
arsenate of lead as follows: (1) Immediately after the petals fall; (2) When the fruit 
^ne pound arsenous oxide (AS 2 0 3 ) will make 3.509 or 4.545 pounds of arsenate 
of lead depending upon process. Not knowing the formula of brand used the 
writer has used the smaller figure 3.509. 
