CARROT FLY ATTACK. 117 



Note on Prevention of Carrot Fly attack received after tfie eariy 

 part of tliis Report was in type. 



In the course of various communications with which I was favoured 

 on matters of insect prevention by Mr. Eobert Turnbull (Inspector of 

 Technical Education under the Aberdeen County Council), he was 

 good enough to give me the following observations of success in pre- 

 venting loss from Carrot .Fly Root-maggot by use of waterings of soft- 

 soap and paraffin oil mixtures, largely diluted with water. These I 

 was not able to introduce in proper alphabetical order of crops, but 

 still do not like to omit what may be very useful, and therefore insert 

 them here as a note with this explanation. 



Carrot-maggot, as is well known, is the small legless yellowish 

 grub, about a quarter of an inch long, of the Psila rosa, or Carrot Fly, 

 a greenish-black two-winged fly, with a rusty- or ochre-coloured head, 

 and ochre-coloured legs ; and the attack is started by the Carrot Fly 

 gettiug down through the earth by means of cracks, or otherwise, close 

 to the Carrot-roots, and there laying their eggs, from which the 

 maggots hatch, and gnaw galleries into the Carrot, thus causing the 

 damage commonly known as " rust" from the peculiar colour. With 

 quite young Carrots the attack is chiefly at the lowest end of the root. 



Measures of cultivation, manuring, dressing, &c., calculated to 

 keep the soil in such condition as will not admit the fly, and manage- 

 ment at time of thiuniug, which is the most hazardous of all periods 

 to the crop, have been given in previous Reports on the authority of 

 good Carrot-growers ; but in the past season I received the following 

 communication from Mr. Eobert Turnbull, Inspector of Technical 

 Education under the Aberdeen County Council, 7, Chanonry, Old 

 Aberdeen, N.B., on the subject of an application which had been so 

 generally found useful as a preventive of " rust," that I give it as sent 

 me. I may mention that I have been indebted for other good com* 

 munication and coUeagueship in work to Mr. Turnbull, and it will be 

 seen that in this case we are also indebted for consideration of the 

 subject to Mr. Malcolm Dunn, Horticultural Superintendent, Dalkeith 

 Palace, the value of whose advice can hardly be over-estimated. Mr. 

 Turnbull wrote me on the 25th of October as follows : — 



" In your ' Text-Book ' I just learned of the efficacy of paraffin 

 against certain insect-attacks, and as you mentioned Mr. M. Dunn, of 

 Dalkeith, who is one of my fellow-councillors of the Edin. Bot. Soc, 

 I took occasion to consult Mr. Dunn in person about the use of paraffin ; 

 and after advising many people in Aberdeenshire to use it for the 

 Carrot crop, I find that good crops of Carrots can now be got, where 

 formerly they always succumbed to the maggot-attack, 



