1922 ENTOMOLOGICAL SOCIETY. 33 



first generation of flies oviposited. On this information we laid down the 

 following plan which has been followed now for three years on commercial plant- 

 ations of from eight to ten acres and results have been checked against the 

 poisoned bait experiments. At the time the seed is being sown in the main 

 plantation or following the seeding operations, plant a row of cull onions, held 

 over from the previous year's crop, every 100 feet through the plantation, setting 

 them about four inches deep and about six inches apart in the row. Allow these 

 culls to sprout and grow so that when the seedlings are an inch high, the volunteer 

 growth is 6 to 8 inches. Pull up and burn these volunteers about June 15th or 

 at the time when the greatest number of first generation larvaa are present in 

 them and before pupation occurs. 



Time and space does not allow us to present the data covering this "trap 

 crop" method of control or the records on the poisoned bait measure as obtained 

 at Vernon, B.C.. but we hope at some later time to do so. 



(A) Showing pallid, sickly appearance of mite-injured plum foliage; 

 (B) Normal plum foliage. (Reduced) 



NOTES ON THE PLUM SPIDEE MITE OR EUROPEAN RED MITE. 



W. A. Ross and W. Robinson,. Dominion Entomological Laboratory, 

 Vineland Station. 

 The following paper on the Plum Spider Mite is largely based on orchard 

 observations made from 1914 to 1921, and on life history studies conducted 

 during 1921 by the junior writer. 



History and Distribution. 

 The Plum Spider Mite or European Red Mite (Paratetranychus pilosus Can. 

 and Fanz.) is an European species which doubtless was introduced into Canada on. 

 imported nursery stock. It was first noticed in Ontario in 1912 by Caesar (1), 



