ys 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. 1.) 
The 1907-8 records were taken mostly from large apricot trees, and 
those for 1908-9 from apricot, prune, and peach trees. 
Tasie III.—Records of larve of the California peach borer taken from trees, 1908-9. 
Num- | Num- 
Number ber of | ber of otal ain Number | 
; of trees Kind of | larvee | larvee | number | Number | empty = 
Date. exam- tree. small | half to of of pupz.| pupal Remarks. 
ined. to half} full larve. cases. 
grown. | grown. 
1908. | | | 
May.” (/5|-seeseo-=- Prune-e cep sees eee fete cre Several | 0 0 | Prunes on Myrobalan 
; plum root, and not 
badly infested. 
5s Sate S| Fo PRESS pee iS ae eels eca cares erent Several 0 | 
LS Bes 2 SA Se oo eee ae 8 ne nae 2 0 : 
23 iT See See ees ees 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 Zale oa Ose steps QRS Lesa: laws oo ancers 15 4| Both trees completely 
girdled. 
June 18 10 | Peach... ..} 8 33 41 0 0 
19 1 SOO | 11 75 86 2 0 
20 | Bal fae Lae severe | 9 63 72 14 0 
July 14 2 | Apricote -. z | 1 a 23 17| Trees almost com- 
: pletely girdled. 
20 Oecd Oi 2 ees 0 | 12 12 10 47 | Both trees completely 
girdled. 
Nov. ©5 Fa On = Sess 9 16 25 0 0 
6 Grieendon ae 16 46 62 0 0 | One tree contained 8 
larve, 7 of which 
were in crotches 
above the ground. 
Dees 18 Ape OOR a cea lege ers eet 113 0 0 
1909. | 
Jan. 5 PRs & 3010 es chal ee ee Meese ss 67 0 0 | Larvee were of all sizes. 
Feb. 5 Nile oko) 1 0 | Larve in this record 
mostly small; one 
seer 76 13 89 
larva in newly 
formed cocoon. 
