THE BLACK-CURRANT GALL-MITE. 5 



wet grass or leaves, wet wooden boards 12 by 6 inches, or plant 

 pots filled with wet grass, should be left on the floor of the 

 conservatory or potting house over night and examined next 

 morning. 



Where they occur in large numbers in the open garden they 

 are a much more difficult pest to deal with, but even here continued 

 trapping has considerably reduced their numbers. 



THE BLACK-CURRANT GALL-MITE. 



Eriophyes ribes (Nalepa). 



The previous experiments* 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 labour 

 involved, although certain growers have given the sprayfluid 

 mentioned in my earlier Report a trial with very satisfactory 

 results. 



The two main objections to the soap and sulphur sprayfluid 

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

 my experiments, and, secondly, the large quantity of soap used. 

 But once having proved that the mite could be destroyed by the 

 use of sulphur, it remained to be demonstrated in what form it 

 was best applied, and whether or not it could be shown that any 

 benefit resulted from a smaller number of applications. 



With these two objects in view, a series of experiments was 

 commenced early in 1905 on a piece of land set apart and prepared 

 for the purpose by the Council of the University of Birmingham. 



On this plot seven rows of bushes were planted, consisting of 

 Black Naples, Baldwins, and Boskoop Giant. All were as badly 

 infected with " big bud " as it was possible to obtain ; indeed, I 

 have never seen worse. The plot of land was far from an ideal 

 one, and the last that a fruit-grower would have chosen, so that 

 the bushes had no natural advantages in their favour. 



The experiments carried out were as follows: Rows, I, 2, 

 and 3 were dusted with equal parts of unslaked lime and flowers 

 of sulphur. Rows 4, 5, and 6 were sprayed with a mixture con- 

 sisting of i Ib. lime, I Ib. sulphur, and 20 galls, water; whilst Row 7 

 was sprayed with a mixture consisting of I Ib. sulphur, I Ib. soft 

 soap, and 20 galls, water. 



DUSTING WITH LIME AND SULPHUR. As it was desirable to 

 find, if possible, the minimum number of applications that would 

 give successful results, Row I was dusted three times, Row 2 twice, 

 and Row 3 once. The dustings were applied when the bushes were 

 wet on March 3ist, April I4th, and Mav 5th. A small pair of 

 bellows were used for the purpose, but better results have since 

 been obtained by the use of the " Coronette " Knapsack Sprayer. 



* Rept. on Economic Zool., No. i, 1904. 



