October, *20] 
PETERSON: ORIENTAL PEACH MOTH 
393 
infested twigs and on some trees the infestation was not appre¬ 
ciably reduced. This season instead of carrying on extensive orchard 
experiments most of the tests were conducted at the laboratory and 
on small individual trees. Under these conditions we could carefully 
watch the behavior of the larvae. 
The following tables show the results of placing individual (usually 
no more than one on a twig or fruit) larvae on treated, freshly cut, 
peach twigs and treated, freshly picked green fruit. When liquid 
sprays were used, the material was applied with a small hand atomizer 
in such a way as to thoroughly coat the twig or fruit. Casein-lime 
composed of 50 per cent casein (lactic) and 50 per cent hydrated lime 
was used as a spreader for some of the liquid sprays. The larvse 
were placed on the liquid treated twigs and fruit as soon as they were 
dry. The dusts were placed in a small hand dusting bag which was 
made of two thicknesses of fine mesh cheese-cloth and then shaken 
onto the twigs or fruit. 
In Tables I and II the larvse used in the experiments varied in length 
from 5-9 mm. while in Table III the exact size of each larva was 
known. In Table III the larvse have been grouped into three sizes, 
2-4, 5-6, and 7-9 mm. Larvse larger than 9 mm. were not used be¬ 
cause the majority of them (upon removal from a twig) show a strong 
tendency to seek a place to build a cocoon and pupate rather than 
reenter a new shoot or fruit. Whenever material was needed for experi¬ 
ments, newly infested twigs were collected from nearby orchards and 
the larvse were removed. They were immediately placed on newly 
treated, freshly cut twigs or fruit. The cut ends of the twigs were 
placed in water to keep them fresh while the individual peaches were 
each placed under a separate glass dish. Observations on most every 
test were made 12, 24 and 48 hours after the start of each experiment. 
The observations recorded in the tables were taken 48 hours after the 
experiment was started. This gave sufficient time for the poison to 
act on the larvse provided they consumed the same. In order to be 
sure of this point observations were always made at the end of three to 
five days with each substance tested and in no case was there any 
change in the results compared with the 48 hour record. In most 
instances the larvse had entered or started to enter the twigs or fruit 12 
hours after they were placed on the same. If they did not enter in this 
period they usually refused to do so. Many of the larvse recorded as 
lost or in the column showing no injury or no larva seen, were present, 
alive and active at the 24 hour period, but for some reason disappeared 
by the 48 hour period. They may have become dislodged while wan¬ 
dering over the smooth surface of the twigs or it is probable that some 
of them were poisoned. 
