THE CALIFORNIA PEACH BORER. 



85 



The trees were examined from time to time, and injury from the 

 oils was soon apparent. Early in October most of the leaves on the 

 trees in plats Nos. 2 and 3 had fallen, and the remainder of the leaves 

 were curled and nearly ready to drop. There was a marked contrast 

 between the oil-treated trees and those which were treated with the 

 lime-oil wash or which were not treated at all. Trees treated with 

 the lime-oil wash were apparently in normal condition. The oil- 

 treated trees again in the spring of the following year were in a 

 weakened condition, and by June 1 trees No. 13 in Plat II and 23 

 and 25 in Plat III were dead. All trees in Plat I and the adjoining 

 check trees were in normal condition and possessed a bright, healthy, 

 green foliage. It is very evident that peach trees can not be safely 

 treated with crude oil alone, although the lime-oil combination 

 appears altogether safe. The trees in this experiment were exam- 

 ined from time to time to notice any new infestation of the insects, and 

 no worms or pupse or pupal cases were ever found on any of the 

 treated trees, although numerous worms infested the surrounding 

 check trees. 



In addition to the attack which would normally be made by moths 

 living in the open field, several trees were subjected to attack by 

 placing fertile eggs on them as in experiment No. 1. Table IX 

 shows the number of the eggs, where they were placed, and the 

 results of examination of trees June 10, 1909. 



Table IX. — Details of experiment No. 2 with protective washes against the California 



peach borer. 



Plat 

 No. 



Tree 

 No. 



Number 

 of eggs. 



Number 

 hatched. 



Date of 

 hatching. 



Num- 

 ber ma- 

 tured. 



Remarks. 



I 



6 



8 



11 



22 



163 



41 



144 



225 



150? 



34 



136 



216 



1908 



Aug. 17 



Aug. 12 



...do.... 



Aug. 13 



None. 



None. 

 None. 



None. 



No larvae, pupae, or pupal cases taken from 

 > any of the treated trees, although infestation 

 was common in adjoining check trees. 



II 



Ill 



Total.. 





573 536 









- 







"WORMING" AND APPLYING WASHES IN THE SANTA CLARA VALLEY. 



The method of controlling the borer as practiced by orchardists 

 in the Santa Clara Valley is to ''worm" the trees by hand during 

 the winter or spring months and later apply a protective wash before 

 the dirt is thrown back. Some orchardists, however, dig the borers 

 out without giving any subsequent treatment. The digging out 

 process is the most important and most effective. The earth is 

 shoveled away from the crown of the tree, the dirt and old bark 

 scalings are scraped off, and the worms are cut out by hand. An 

 ordinary three-fourths-inch wood chisel and a horseshoe knife are 



71419°— Bull. 97—12 7 



