MITES 539 



another season. The life-history of these minute organisms, 

 which are not quite ^^yinch in length, is but imperfectly known. 



The mites are readily dispersed by wind, insects, clothing 

 of persons moving amongst the bushes, and more especially 

 by using diseased portions of plants for propagation. By 

 such means new areas of infection are established. 



Unfortunately no certain cure is known. Picking by hand 

 of the infected buds is the most effective preventive method ; 

 the swollen infected buds should be burned. Theobold 

 says that from repeated observations he has found that the 

 bud above and the bud below an infected one contains mites, 

 and that these should be removed along with the infected 

 one. The same authority states that cuttings can be safely 

 disinfected by immersing them in water for some days before 

 setting. Cold water has been found quite successful if left in 

 it for a couple of days. A better treatment was found by 

 Pickering, namely, of immersing the material in water at 

 115 F., for ten minutes before planting. 



Some years ago I conducted some experiments at Wisley, 

 for the purpose of devising some method for the extermination 

 of the ' big bud ' mite, and found that covering the branches 

 of a badly infected bush with grease or vaseline effected this 

 object. Not being in the same rut as those dealing with 

 mites, the suggestion of such an idea brought down a whirl- 

 pool of indignation accompanied by ridicule ; nevertheless 

 it answered the purpose when tried by unbiassed minds. 



The procedure is briefly as follows, based on the facts that 

 the mites migrate from the old, dead, infected buds to newer 

 parts of the bush during late spring and early summer, and 

 that the said mites become entrapped and held fast when 

 they attempt to walk on a greasy surface. The shoots of 

 infected bushes should be coated with cart grease or some 

 similarly sticky substance, applied with a brush. The dis- 

 eased buds need not be picked off, as when they are coated 

 with grease the mites cannot escape. A fuller account of the 

 process, with replies to criticisms, will be found in Journ. Roy. 

 Hort. Soc, 38, p. 163 (1907). 



Collinge, W., Rep. Injurious Insects and other Animals in 

 Midland Counties, p. 6, 1904. 



Lewis, E. J., Journ. S. E. Agric. Coll., No. n, p. 55-80 

 (1902). 



Theobold, F. V., Insects and Pests of Fruit Trees, p. 231 

 (1909). 



