62 



THREE BRITISH FRUIT-TREE PESTS LIABLE TO BE INTRODUCED 

 WITH IMPORTED NURSERY STOCK. 



By Frederick V. Theobald, Wyecourt, England. 



The subject of the importation of injurious insects from one country 

 to another is a most important one. That man}^ European pests have 

 been imported into America and into the British colonies is well known. 

 These unwelcome visitors, finding- their new surroundings abnormally 

 congenial and their natural enemies absent, often cause far more harm 

 than they do at home. It is unnecessary to mention examples so well 

 known to all interested in economic entomology. The study of the 

 insect pests of other countries than our own is thus rendered very neces- 

 sary, so that we may be prepared to fight and prevent the new arrivals. 

 This distribution of noxious creatures is most important in regard to 

 fruit and ornamental plants. The notes on three British fruit pests 

 which maj" easily be introduced into America may therefore not be 

 unwelcome to the members of this Association. The three pests that 

 appear to me to be especially guarded against and which I believe do 

 not occur in the orchards and gardens of America are the following: 

 The pith moth (Laverna atra) ; the apple sucker (Pyslla mail) ; the 

 currant- bud mite (Eriojihyes ribis). 



All these pests occur permanently on trees or bushes in one or more 

 of their stages, the winter in all cases being passed upon the plant, the 

 pith moth in the larval stage, thepsylla in the egg condition, and the 

 currant bud mite in all stages. They can therefore be easih 7 trans- 

 ported on nursery stock. 



It may be said that the fumigation of the } r oung plants or cuttings 

 with hydrocyanic-acid gas will prevent their introduction, but from 

 experiments I have made I am confident that the ova of the psylla and 

 the bud mites are not in the least harmed by the treatment, and I 

 doubt if the effect of this gas would kill the larvse of the pith moth in 

 question. 



The apple sucker and the big-bud mite of the black current are both 

 such serious pests that great caution should be exercised in importing 

 stock from England and Europe. For the latter pest we have abso- 

 lutely no remedy, and the former is most difficult to fight. 



THE PITH MOTH. 



(Laverna atra Haw.) 

 Syn. : L. putripennella Zell. 



This small Tineid moth has long been known in Europe b} T ♦ento- 

 mologists, but it was not recognized as a pest in Great Britain previous 

 to a short note made by Miss Ormerodinl890; a few subsequent notes 

 were added by her, but nothing of any special value or originality. 



