THE CALIFORNIA PEACH BORER. 



83 



NATURAL ENEMIES. 



There is a species of ant which has been observed many times to 

 attack adult moths, pulling them to pieces and literally eating them 

 alive. It often happened that a moth would become entangled in the 

 creases of the wire mesh or in the cotton of our trap cages where the 

 traps were bound around the tree. Almost invariably their bodies 

 would soon be torn to pieces by these ants. The ants presumably 

 are not of economic importance in controlling the moth of the borer. 



On another occasion a nest of small white mites was taken from the 

 body of a dead moth, as well as a dipterous larva. 



METHODS OF CONTROL. 



EXPERIMENTS WITH PREVENTIVES. 



Six large apricot trees in the insectary yard were treated as follows : 

 The dirt was first dug away from the lower trunks to a depth of 8 or 

 10 inches, the bark was scraped, the few worms present were removed, 

 and the lime-oil wash was applied over the newly exposed bark and 

 to a height of 16 or 18 inches above the ground. The mixture was 

 swabbed on thickly with a large calcimining brush and was applied 

 on June 25, 1908. 



On August 4, 1908, six weeks later, numerous clusters of eggs just 

 ready to hatch were selected from the rearing cages and attached to 

 the treated trees at a height of from about 5 to 10 inches above the 

 ground, where they would normally be placed on untreated trees in 

 the open field. This experiment was made under extremely unnatural 

 conditions, because eggs are apparently never placed directly on 

 any treated surface. It served our purpose, however, which was to 

 determine the number of young that could really penetrate through 

 the wash and get into the tree. The wash was still in a good condition 

 on August 4, when the eggs were attached. Table VIII gives the 

 details of the experiment and the results of examination of trees 

 September 21. 



Table VIII. 



-Details of experiment No. 1 with protective lime-oil wash against the 

 California peach borer. 



Tree No. 



Number 

 of eggs 

 placed 

 on tree. 



Position of eggs on tree. 



Number 



of eggs 



hatcned. 



Date of 

 hatch- 

 ing. 



Remarks. 



1 



2 



4G 



85 

 78 



154 



74 



248 



5 inches above ground on north side 



of tree. 

 do 



43 



42 

 75 



139 



71 



210 



Aug. 12 



...do 

 ...do.... 



Aug. 25 

 ...do 

 Aug. 26 



No sign of borers found. 

 Do. 



3 



do 



3 empty pupal cases 



found. 

 No sign of borers. 

 3 empty pupal cases. 

 No sign of borers. 



4 





5 

 6 



2 inches above ground 



On lower trunk 





Total 







685 



580 



6 moths matured. 









