188 



TURNIP. 



Diamond-back Moth. Plutella cnuifcrarum, Zeller. 



Plutella ceucifeearum. 



1, caterpillar ; 2, eggs ; 3, Diamond-back Moth (all natural size) ; 4, 5, Diamond- 

 back Moth, at rest and flying (magnified). 



The first reports of appearance of Diamond-back Moth infestation 

 were much earher in 1892 than in the notable attack of the preceding 

 year. Then, so far as appears, no notices were received pointing to tlie 

 coming trouble until when early in July the caterpillars were reported 

 as doing much harm at a locality on the Yorkshire coast, and later (on 

 the 17th and 20th of the same month) the first observations of severe, 

 injury on the Scottish coast heralded the long train of notices of 

 serious mischief. Subsequent enquiry showed the moths to have been 

 observed, and duly identified, some weeks earlier, the first record 

 given being on the 24tli of June. 



In the year now past (1892), the infestation was recognised on its 

 first appearance in moth state, so that we were prepared for what was 

 coming. Mr. Edw. A. Atmore, F.E.S., writing from King's Lynn, 

 Norfolk, informed me : — "This year I first noticed Plutella crnciferarum, 

 the Diamond-back Moth, in the neighbourhood of Lynn, on the 17th 

 of May, and from that time their numbers seemed to be on the 

 increase ; so much so that on the 29th of May when at Westwick, 

 near this town, they seemed to be everywhere." 



On the 28th of May, Diamond-backs were sent me as samples of 

 the species of moths then flying in large numbers over fields near 

 Pocklington, in Yorkshire ; and on the 31st of the same month, Mr. 

 Andrew Balsillie, who had paid careful attention to this attack in 

 1891, reported the recent appearance of the moths in considerable 

 numbers on St. Andrew's Links, and also that it was present on the 

 neighbouring fields. On the same day reports were also sent me of 

 the appearance of the Diamond-back Moths in considerable numbers 

 near Crail, also in Fife, and also near Errol, Co. Perth, N.B. 



