DIAMOND-BACK MOTH. 



149 



panying of caterpillars of Diamond-back Moth, some spun up. Mr. 

 Muirliead wrote that he was sending a young Turnip with specimens 

 of caterpillars found on its leaves, and on those of adjoining Turnip 

 plants, and desired to know whether the insects were of the same 

 species which were destroying the crops in various parts of the 

 country : — 



" The Turnips were first showed to be affected by the insects about 

 two days ago ; and five or six acres of the field in which they first 

 appeared have been completely eaten up, so far as the leaves are 

 concerned." 



Eeplies to inquiries in circular (see p. 110), August 24th : — 



(1). " No rehable estimate can be given. The damage done by the 

 caterpillar is much greater in some localities than in others. Much 

 loss has been suffered in the vicinity of Udny Village. 



(2). " No measures were adopted. One proprietor purchased a 

 Strawsonizer with the view of applying superphosphate, but before he 

 got it used the heavy rains cleared off the caterpillars. 



(3). " The benefit of heavy rains was so great that no further 

 measures were needed to get rid of the caterpillars. 



(4). " Light brown sandy loam. Autumn cultivated ; ploughed 

 about seven or eight inches deep. Manures — bone meal, superphospate 

 and slag ; no salt. 



(6). " Weather and weeds as usual. Weather was dry at seed- 

 time of Turnips. 



(6). " The caterpillars were observed to frequent Charlock. 



(7). " No birds were observed to be eating the caterpillars." — 

 G. M. 



On the 7th of January, in the present year, 1892, Mr. Geo. Muir- 

 head, writing from the Estate Office, Haddo House, Aberdeen, kindly 

 favoured me with the following information in reply to my inquiries 

 as to ultimate extent of injury from caterpillar attack : — 



" So far as my own observation has gone, it has appeared to me 

 that where the moth caterpillars had done much damage to the leaves 

 of the young Turnips they never recovered from its effects ; and where 

 the foliage was only partially destroyed the diminished crop showed 

 that the constitution of the plants had been injured. On many farms 

 in this district, if not on all, the Turnip crop this season is considerably 

 below the average, the result it is thought of unfavourable weather 

 generally, combined in certain localities with the attack of the cater- 

 pillars of the Diamond-back Moth."-G. M. 



To the above Mr. Muirhead added the following communication 

 written on Dec. 29th (1891) by Mr. David Walker, of Coullie, Udny, 

 Aberdeenshire, with the remark: — "I have now the pleasure of 

 enclosing a letter which I have received from one of the principal 



