216 SCIENCE AND FRUIT GROWING 



buds. The whole of the bushes at Woburn were cut down after 

 these experiments had been concluded, but the new growth 

 which came up was, apparently, as badly infested as the old : 

 two years later they were again cut down, as well as all the red 

 and white currants in the ground for it has been proved that 

 the mite may occasionally exist in the red currant; yet the fresh 

 growth was still infested. Such cutting down, if performed 

 every year for either two or three seasons, and accompanied by 

 a careful removal of all buds found to be affected, has proved 

 to be effective in some localities (e. g. Holmes Chappel), and 

 has, in consequence, been recommended by the Board of Agri- 

 culture ; but it has proved ineffective at Woburn. On two 

 separate occasions, at an interval of many years apart, planta- 

 tions were treated in this way, and under the direction of a 

 manager who had applied the method successfully at Holmes 

 Chappel; but in both cases, after some promise of success at 

 first, the procedure had to be abandoned as a failure (XIV, 72). 



Fumigation of the bushes by means of hydrocyanic acid was 

 also examined, each bush being enclosed in a box covered with 

 tarred felt, and the proportions of potassium cyanide used being 

 I ounce to every 150 cubic feet of air space. The results were 

 altogether unsatisfactory, as, also, were those of a similar treat- 

 ment with a substance consisting of nicotine and camphor, 

 known as " XL All." Subsequently to these trials, H. H. Cousins 1 

 claimed to have obtained success in treating bundles of cuttings 

 and young bushes with hydrocyanic acid ; but experiments on 

 the treatment of bushes in situ, though suggested, were not 

 described. The treatment of cuttings or young bushes before 

 plantation may be successful, but it is a question of but little 

 importance, for cuttings should never be taken except from 

 bushes which are quite clean : and, though fumigation may 

 conceivably under favourable circumstances kill the mites, it 

 is extremely improbable that it would kill their eggs, and these, 

 according to Newstead, are present in the buds during every 

 month of the year (II, 34). Fumigation of a small bush would 

 be likely to yield very different results on different occasions, 

 for the gas is soluble in water, and very different quantities of 

 it would be absorbed by the soil according to the condition 

 of wetness obtaining in it. 



Further experiments were made at Woburn as to the possi- 

 bility of killing the mite by dipping the bushes in hot water. 

 Such treatment, like fumigation, could not be regarded as being 



1 Journ. of S.E. Agric. Coll., Wye, 9, 67. 



