15 



CELERY. 



Celery-stem Ply. PiopUla apii, Westwood. 



Celery stem injured by maggot borings. 



The attack of the Celery and Parsnip -leaf Fly, of which the maggot 

 (in some years) does enormous damage by burrowing between the 

 upper and under side of the leaf, and consequently destroying it in 

 large patches, is well known; but the great mischief sometimes caused 

 by the maggots of another kind of two-winged fly tunnelling in the 

 lower part of the Celery stem, is apparently of much rarer occurrence. 



On the 29th of July, Mr. Edw. Kiley, of the Weir, Hessle, near Hull, 

 when writing to me of some insect injuries which had been occurring at 

 Epworth, added, "But the most serious attack is on twenty acres of 

 Celery (Mr. Blaydes grows seventy-eight acres) : a white grub, the size 

 of the caterpillar on the Cauliflower {i. e., about half an inch long. — 

 E. A. 0.), had completely eaten ofif the plants, about an inch within 

 the ground ; you could go down the rows and see all the tops pulled up. 

 I never saw such destruction, scarcely a plant in a hundred left 

 growing," . ..." It appears to be something new. Last year they 

 had a slight attack ; it seems to be spreading in the district." 



Specimens of the infested plants were forwarded me by the owner, 

 drawing ray attention to the destruction of the tissues of the root by 

 the grub, and on examination I found the attack corresponded with that 

 described by Prof. J. 0. Westwood,* as caused by the infestation of 

 maggots of the Celery- stem Fly, scientifically the Piophila apii. The 

 above figure, which is taken mainly from that by Prof. Westwood, 

 gives an idea of the stem when moderately attacked. 



I found, in the plants sent me, that the thick base was pierced by 

 workings in which the larvne, or maggots, were present, and the lowest 



* See vol. of ' Gardeners' Chronicle ' for 1848, p, 332. 



