136 THE CANADIAN ENTOMOLOGIST 



SOME NOTES ON THE ERIOPHYID.E (ACARINA) 

 IN BRITISH COLUMBIA. 



BY R. GLENDENNING, 

 Duncan, B.C. 



In 1908 the writer noticed an infection of Big Bud on some black currant 

 bushes that had been imported from England to a nursery on Vancouver Island. 

 The affected bushes were destroyed, but in 1914 this pest was again noticed on 

 bushes in a private garden which had been supplied from this nursery. 



Upon the attention of the Dominion Entomological Branch being called 

 to this through their Field Officer for British Columbia, Mr. R. C. Treherne, 

 this officer and the late Dr. Hewitt visited the affection, and a thorough inspec- 

 tion was arranged for and made under the Provincial Department of Agricul- 

 ture. This resulted in the finding and destroying of nearly eight hundred bushes 

 which had been distributed from the nursery to various places on \"ancouver 

 Island. The possibility of the pest spreading to the various wild species of 

 Ribes was not lost sight of; but it was not until 1916 that some bushes of Ribes 

 bracteosum Dougl. (the wild black currant frequent by stream sides on the 

 Pacific slope) were quite accidentally noticed to be affected. 



These had apparently become affected by cuttings of infected bushes 

 being placed, by a farmer for rooting purposes, in the sandy alluvium of a stream 

 bed about one-half mile up stream; some of the cuttings being afterwards washed 

 out by a flood. These bushes are still bearing the affection, though the mite is 

 not making much headway. 



Big Bud, I might here state for the benefit of those unacquainted with the 

 pest, is caused by a true mite, which living hidden in the tightly-folded buds 

 of the black currant sucks the juices therefrom, causing the buds to swell, be- 

 come spherical instead of pointed, and finally to drop off during the summer 

 without having expanded properly. Many hundred mites are located in one 

 bud, and when the adult stage is reached in spring the mites migrate to the 

 new buds. The result is partial, or in unchecked cases, total defoliation of the 

 bushes; and from the fact that the mites are hidden in the buds for the greater 

 part of the year and are so small when they do come out, intelligent spraying is 

 very difficult and burning the affected bushes is usually resorted to, to get rid 

 of this pest. This was the first record of this pest in N. America. 



At Agassiz, on the Mainland, the frequent affection of the native hazel 

 {Corylits calif ornica Rose) with a similar mite was noticed; the pest having a 

 good hold on this plant which is very common in some parts of the Eraser Valley, 

 and eventuallytwo other native shrubs were noticed affected with the same mite, 

 namely, Ribes lacustre, a very spiny gooseberry-like shrub, and Ribes bracteosum, 

 the wild black currant — the same species that became affected on \'ancouver 

 Island with the escaped European mite. 



A very interesting point is here raised by these discoveries regarding the 

 specific identity of the mites on these plants, both in British Columbia and 

 England. In England four species are commonly mentioned in reference 

 books, namely, Eriophyes avellana, E. ribis, E. grossularice, and E. pyri, being 

 named from their respective hosts. The last named, E. pyri, the common 

 Pear leaf blister mite does not now interest us. The other three are not con- 

 sidered specifically distinct by some authorities in England and the findmg of 



June, 1920 



