72 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 
which hatch during the midsummer or in the fall usually mature 
during the same period of the following year. If, however, a tree 
has been weakened or is near to its death, the borers will invariably 
mature in the early spring or summer, when their life cycle will be 
much less than the regular twelve months. 
Monthly worming records were made during a period of about 
two years, and although for many reasons these records can not be 
compared they offer much of interest. The first plan—to mark off 
a badly infested orchard into uniform plats and to dig all of the 
worms regularly from month to month on each of these plats—was 
not entirely satisfactory. The infestation in any orchard is extremely 
variable. One tree may harbor from 50 to 70 or more larve, while 
those immediately surrounding may be entirely immune. It was 
necessary, therefore, to find infested trees regardless of the position 
in the orchard when each record was made, and all worms which were 
collected on any one date, although they may have been gathered 
from many trees in various parts of the orchard, constituted the 
basis for the record for that particular period. Some trees would 
harbor 1 or 2 and others from 50 to 70 worms. (See Pl. X, fig. 12 
The 1907-8 records were taken mostly from large apricot trees, and 
those for 1908-9 from apricot, prune, and peach trees. 
TasLe III.—Records of larvx of the California peach borer taken from trees, 1908-9. 
Num- | Num- 
Number ad Hes of pee of le ae eee 
of trees Kind o arvee | larve | number umber | empty 
Date. | exam- tree. small | half to of of pupz.| pupal Remarks. 
ined. to half} full larvee. cases. 
grown. | grown. 
1908. 
May a (Site ee ci IPTUNG2ec oe |e aac lease ec Several 0 0 | Prunes on Myrobalan 
plum root, and not 
badly infested. 
Itsy ls Says $ocl Geer Sas e SB ee EERE Sr eenal sae oraer ee Several 0 
LB al Rae ceceers isis cee. ce esse lance cette Henk cok onl sec cee ace 2 0 
23 WOM es Sete. Sel eostents- Many Many 10 8 | Pupeandempty pupal 
cases from dead trees; 
hence very advanced 
stage of insect. 
24 4| Apricot... 7 127 134 19 0, All trees completely 
girdled; most worms 
were nearly grown. 
26 2 dos. =6-- Onleceter S| beers oeias 15 4] Both trees completely 
girdled. 
June 18 10 | Peach 8 33 41 0 0 
19 1h Ieee (0 ier 11 75 86 2 0 
20 Bee edoaes aoe 9 63 72 14 0 
July 14 2 | Apricote .. Zz 1 3 23 17| Trees almost com- 
pletely girdled. 
20 ZiiesedOnea ke 0 12 12 10 47 | Both trees completely 
girdled. 
Nov 5 Si sedosee.. 9 16 25 0 0 
6 Galeacdoe at eee 16 46 62 0 0 | One tree contained 8 
larve, 7 of which 
were in crotches 
above the ground. 
Dec 8 4 GO. oh | Sececee ale osesoe 113 0 0 
1909. 
Jan. 5 hl FRAG ce |e oa | See ee 67 0 0 | Larvee were of all sizes. 
Feb. 5 6 dome. 76 13 89 1 0| Larve in this record 
mostly small; one 
larva in newly 
formed cocoon. 
