120 ASSOCIATION OF ECONOMIC ENTOMOLOGISTS. 



Very briefly, the results which have accrued from this investigation 

 are as follows: 



(1) The life history has been repeatedly worked through and 

 valuable data obtained as to the dates of egg laying, the first appear- 

 ance of the mites, when the old infested buds dry up, when migration 

 commences and ceases, when the mites were found in the new buds, 

 and the eggs, the dates the mites were last seen, and the dates the 

 new buds commenced to swell. These details have been recorded for 

 eight consecutive years. 



(2) Two points of considerable interest have, I think, received a 

 satisfactory solution, viz, first, what becomes of the mites which fall 

 off the trees? And, second, do the females continue to lay eggs 

 throughout the year? 



Hoping to obtain some solution of the first problem, I devised, early 

 in May, 1903, a wooden frame in two halves, lined with black paper, 

 which fit closely round the stem of a currant tree. From the end of 

 May to the end of June thousands of mites were to be found on the 

 tray. Many were dead, but the majority alive, and although a very 

 careful watch was kept, none was ever found to return to the tree, 

 but in some manner or other, possibly by attaching themselves to 

 insects, they gradually disappeared from the tray. The percentage 

 of dead mites was about 10 per cent. 



A similar tray, filled with a fine layer of soil, gave similar results, 

 only here the mites were much more difficult to trace. As a result of 

 the above experiments, I conclude that of the mites which fall to the 

 ground during the migration season many are distributed by insects, 

 birds, leaves, etc.. to other trees, the remainder dying. 



About the middle of June eggs and mites in various stages of devel- 

 opment are to be found in the center of the new buds. During the 

 winter of 1902-3 one or more buds were examined once a week from 

 September to March, and in nearly all cases eggs were found to be 

 present. They were certainly very few in number from December, 

 1902, to March, 1903, and it seemed to me that many of them were 

 dead. From October 11, 1903, to January 30, 1901, buds were taken 

 from another tree and examined once a week, but in spite of the most 

 careful searching no eggs were discovered after October. 



The previous experiments a on the destruction of this pest, although 

 very successful, were not of the nature that a fruit grower could 

 apply at a cost which would repay him for the extra labor involved, 

 although certain growers have given the spray fluid mentioned in my 

 earlier report a trial with very satisfactory results. 



The two main objections to the soap and sulphur spray fluid were, 

 firstly, the large number of applications which were given in my 



o Report on Economic Zoology, No. 1. 1904. 



