372 



UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



ASPHALTUM TREATMENT FOR THE PEACH TREE BORER. 



The western peach tree borer (Sanninoidea pacifica) is an insect 

 of much economic importance in the horticultural district about the 

 southern arm of San Francisco bay. 



The investigations upon which this paper is based were made in 

 most part in the peach orchard of the J. H. Flickinger Company, 

 Berryessa, California. They have extended over a period of four years. 

 The results have not been verified for other districts. 



The adult borers are slender, blue-black, day-flying moths, about one 

 inch long. They are seldom seen and very rarely recognized by the 

 orchardists. They issue more or less from February to September, but 



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Pig. 5. — Work of the peach tree borer. 



the mass of them appear about the middle of July. They place the eggs 

 on the trunk of the tree from the ground up two feet, one to twenty-five 

 eggs in a place. These are very small and generally escape notice. They 

 hatch in a few days. 



The newly hatched larvge, or "worms," which are difficult to find, 

 usually enter the bark at or near the ground. The new burrow is 

 marked at first by light brown bark dust, which in a few hours dis- 

 appears, after which it is nearly impossible to find the opening. The 

 larvae grow rapidly, work their way through the bark, and spend most 

 of their life between the bark and wood, where they may do great 



