88 AGRICULTURAE RESEARCH AND THE FARMER : 



were no means of identifying bushes which were in the early 

 stages of " reversion," so it was impossible to carry out definite 

 experimental work or to advise growers which bushes to " rogue." 

 After observations extending over three seasons a method of 

 identification, depending on the character of the leaf, was 

 discovered, and definite experimental work was thus made 

 possible.* As a result growers are now in a position to recognise 

 the early stages of the disease and can in consequence rogue 

 both plantations and cutting beds. It has been shown already 

 that this method, if rigorously employed, is sufficient to keep 

 down the disease to a minimum, and to secure paying crops. 

 The recognition of early stages also enables the grower to avoid 

 propagating from diseased stock, a course of action which 

 invariably reproduces diseased specimens. So far the results 

 in the field appear to indicate that the presence of mite in a 

 black currant shoot causes a change of leaf type from the normal 

 to the reverted, thus apparently confirming an opinion that 

 exists among growers that the two diseases are closely associated. 

 If this view is confirmed, the problem of control resolves itself 

 into the securing of clean stocks and the prevention of mite 

 infection. An objection to the view is that certain varieties, 

 such as Seabrook's Black, which in some districts are resistant 

 to " big bud," are yet decidedly susceptible to reversion. In 

 these cases, however, it has been found that the variety is not 

 immune from attack by the mite, but that for certain reasons, 

 the normal swelling of attacked buds does not occur. Work is 

 in progress to obtain further information regarding the associa- 

 tion of " big bud " with " reversion." In the meantime experi- 

 ments are being carried out for the control of mite attack, and so 

 far the most promising method employed has been the apphcation 

 of sulphur sprays. 



Apple Blossom Weevil. — This pest has been very serious in 

 apple-growing centres during the past four years. Eighty per cent, 

 blossom damage has been common. During the past eighteen 

 months the life-history has been investigated and the work has 

 shown the following important results : — [a) That the weevil 

 continues to feed on the leaves during the summer and does 

 not remain without food as previously supposed. Nevertheless 

 laboratory trials have shown that lead arsenate is ineffective for 

 killing them at this stage, {h) That in the early spring the 



* It should be mentioned that as the result of work carried out 

 on this disease simultaneously at the East Mailing Research Station 

 it was found that " reverting " could be usually identified during the 

 flowering season by means of the colour of the blossom ;ind other 

 characters 



