December, '22] duruz: peach twig-borer control 395 



may be put to use as an economical means of combating other insects. 

 The writer has not had an opportunity to try it against clothes moths, 

 but he can see no reason why a vial of mercury in a trunk or closet would 

 not be effective in preventing the hatching of the moths' eggs. If 

 later investigation shows that it will prevent the hatching of these 

 eggs, it would be an economical and convenient method of control, 

 because the initial cost of the mercury would be little, and it would 

 require practically no attention after being placed in the desired lo- 

 cation.- 



PEACH TWIG-BORER EXPERIMENTS IN CALIFORNIA 



(A Preliminary Report) 

 By W. P. Duruz, Pomology Division, University of California 



The peach twig-borer (Anarsia lineatella Zeller) or peach worm, as 

 it is also known, has again become a very serious pest in California. 

 The loss in shipping and canning fruits in 1920 and 1921, due to the 

 damage of this caterpillar, was estimated at between 20 and 60 per cent 

 of the crop. 



Twenty years ago Professor W. T. Clarke\ of the University of 

 California, reported the results of careful experiments conducted in 

 Placer County and recommended spraying with a lime-sulphur-salt 

 mixture at the time the trees begin to blooni. This advice was ac- 

 cepted and fruit growers reported good control. Thus, spraying with 

 lime-sulphur at the time the buds swell became the standard practice in 

 California, for preventing "wormy fruit." 



During the last three years, however, it has been observed that 

 lime-sulphur sprays at this time did not free an orchard of infestation, 

 and the loss caused by this insect became of great concern. Entomolo- 

 ists were not able to remedy the situation because of the lack of ex- 

 perimental work, also on account of the fact that the life history of the 

 insect was in doubt. The effectiveness of present-day spray ma- 

 terials was also an unknown factor that had to be tested. 



The great need for more facts was apparent; therefore Professor 

 E. O. Essig and the writer outlined a project with a view of obtaining 



^The only reference of which the writer has any knowledge is "Mercury as an 

 Insecticide" (abstract) by K. Kunhi Kannan, in the report of the proceedings of the 

 third entomological meeting, held at Pusa, Feb. 3 to 15, 1919, edited by T. B. 

 Fletcher (Entomological Meeting, Pusa, Report of Proceedings, 1919, Volume 2, 

 Pages 761-762.) The writer has not had an opportunity to see this article. 



iQarke, W. T., "The Peach Worm," California Experiment Station Bulletin 

 No. 114, 1902. 



