168 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



It has been stated that the mites are conveyed by birds from one bush 

 to another, and I can quite imagine this to be so, although I have not been 

 able to prove it. I have found mites on the bodies of aphides present on 

 shoots bearing diseased buds, and have also counted seven mites on the 

 body of a ladybird. There is, however, no possibility of the mites being 

 dispersed by birds, insects, wind, or other agents, if they are prevented from 

 lea\'ing the infected buds, by the application of some viscid substance 

 sufficiently early in the season. 



Various comments have been made on the preventive method I have 

 suggested. 



(1) . The application of grease in any form would prove injurious to the 

 bushes. As a reply to this I have already stated that the bushes treated 

 by the various substances enumerated for two successive years are still 

 perfectly healthy and have produced good crops of fruit. The bushes 

 treated with gas-tar afterwards produced the best crop ever seen by the 

 owner, a man of experience. I should not recommend the gas-tar for use ; 

 at the same time the experiment is of value as showing what can be done. 

 The reason why grease does no harm is probably due to the fact that the 

 epidermis or skin of the shoots is shed under the form of a thin membrane, 

 which persists for some time on the branches as a dead, loose covering 

 before it finally falls away. 



(2) The method, even if effective, would be too costly. I have worked 

 this question out on a practical scale, and find that a person could, without 

 any over-exertion, treat forty-eight bushes in ten hours (probably a much 

 greater number could be thoroughly done). Now if we allow four shillings 

 per day for labour and material, which is presumably much more than 

 would be paid, allowing threepence for grease after a brush had been 

 bought, the cost per bush works out at one penny. What the difference 

 in profit would be between a bush bearing no fruit and the same bush 

 bearing a good crop of fruit I have not been able to ascertain ; but if we 

 say a shilling, then even if two applications of grease, costing twopence, 

 were applied there would still remain a profit, even during the first year. 



(3) The method suggested is of very doubtful utility. This, as I have 

 pre\iously stated, can only be determined by persons growing black 

 currants on a large scale. Personal opinion, unsupported by experiment, 

 even when unbiassed, is of little or no value. If there is anything 

 encouraging in the idea the present crude suggestions will soon be im- 

 proved upon, and the only idea involved is that 7?iites cannot walk on 

 grease without being held fast. Probably some mixture that can be used 

 as a spray — say, a mixture of fish oil and resin — will be found to answer 

 the desired object. 



Black Curkaxt and Hazel Gall Mites. 



The opinion is held by gardeners and others that mites from the hazel 

 infect the black currant and produce "big-bud," and vice versa. To test 

 this view from a practical standpoint a number of " Baldwins " very badly 

 infected with "big-bud" were planted in a row with alternating hazel 

 bushes free from "big-bud." The bushes are planted so near to each - 

 other that the currant and hazel branches are intermixed (fig. 40). A 

 second batch of "Baldwins" free from "big-bud" was planted under 



