8 REPORT ON INJURIOUS INSECTS FOR 1905. 



of Eriophyes (E. oleivorus, Ashmead) was undoubtedly introduced 

 in the Rivera and San Diego Bay districts of California, U.S.A.. 

 where it did considerable harm in the orange and lemon groves. 

 Mr. Marlatt states that " an estimate, made from actual count,, 

 indicates that the mites and eggs on a single leaf in midwinter 

 may reach the enormous number of 75,000," indicating some 

 billions of mites for each tree in the active breeding season. He 

 further states that it " is readily destroyed by various insecticides. 

 The eggs, however, are much more difficult to kill, and practically 

 no wash can be relied upon to reach and destroy all the eggs of 

 this .mite. . . . The sovereign remedy for the rust mite is sulphur. 

 .... The advantage of the sulphur treatment arises from the fact 

 that the sulphur adheres to the leaves, and the young mites are 

 killed as soon as they come in contact with it." 



A further example of treating another species of the same 

 genus of mites is offered in the case of the cotton leaf blister-mite 

 (E. gossypii, Banks.), which made its appearance in the West Indian 

 cotton fields in 1903*, and quickly spread throughout the islands. 

 Here the lime and sulphur treatment has proved most effective. 



THE WALNUT GALL-MITE. 



Eriophyes tristriatus v erinea (Nal.). 



This species sometimes proves very troublesome on walnut 

 trees. As yet I cannot give any account of its life-history, and the 

 only remedial measures I know of are dusting or spraying with 

 lime and sulphur, and burning the fallen leaves from infected trees. 



The specimens from which the illustrations were taken were 

 very kindly sent me by Miss S. E. Stow, of Grantham, to whom I 

 am indebted for many other galls formed by mites of this genus. 



THE HAZEL-BUD MITE. 



Eriophyes avellaena (Nalepa). 



The remedial measures mentioned in my last Report have been 

 carried out in a number of instances, with the result that during 

 1905 there has been a considerable diminution in the number of 

 abortive buds. 



A few new cases have been reported, and the lime and sulphur 

 dusting has been tried with excellent results. 



THE LIME LEAF GALL-MITE. 



Eriophyes tiliae (Pgst.), Nalepa. 



The well-known nail-galls on the upper side of the leaves of 

 the lime have been frequently met with during the past season. 

 Unfortunately, time has not permitted the working out of the life- 

 history of this species, although a few important facts have been 

 added to work done in previous years. There is little doubt but 

 that, when the migration period is known, dusting with lime and 

 sulphur will prove an effective remedy. 



West Indian Bu! 1 ., 1903, vol. iv, pp. 282 and 336. 



