OF INJURIOUS INSECTS. 
15 
6. Anthomyia ceparnm. Onion Maggot. 
Mr. Melville observes, writing from Dunrobin, Sutlierlandsliire, 
that this year’s experience lias much strengthened his opinions as to 
the best way to avoid attack of this Fly. (See Report for 1879, p. 12.) 
Mr. Alexander Forbes mentions that an excellent crop of Onions 
entirely free from Maggot was harvested at Skibo Castle, Sutlierland- 
shire; and Mr. Fitch did not observe any attack at Maldon, Essex; 
but in many localities the Maggot was very destructive. The most 
successful remedy for the attack, when found to be established, appears 
to be in the use of paraffin oil; and I place consecutively the descrip¬ 
tions of treatment that include methods of application of this cure. 
Mr. M‘Finlay, writing from Tullocli Castle, Ross-shire, mentions 
that in many parts of Ross-shire the Onion crop suffered much from 
the Maggot, and in some gardens it was a complete failure, the 
summer being dry and apparently suitable to the Onion Fly. The 
only means found serviceable for prevention was the use of sand 
saturated with paraffin oil, and sown amongst the Onions, and this 
afterwards watered by means of a can with a rose. Mr. M‘Kinlay 
experimented on the direct effect of the paraffin by placing some 
Onion Maggots in a flower-pot in soil with some young Onions. On 
the third day (thus giving time for the Onions and their contents to 
be re-established) he introduced three drops of paraffin into the 
flower-pot; and on examination with a magnifying-glass, twenty-four 
hours afterwards, all the Maggots, with the exception of two, were 
dead. Lime water was not so effectual, but proved fatal after a time. 
In the gardens at Tullocli Castle the crop was excellent. The method 
of cultivation is to trench the Onion ground early in autumn, working 
in plenty of manure, and leaving the surface rough to be pulverised by 
frost. About the 10th of March, if the weather is favourable, about 
six or seven cart loads of hen-manure are wheeled on to the Onion 
break previous to forking (care is taken to have the hen-manure well 
turned during the winter, and covered with soil to keep in the 
ammonia). After forking, the ground is well raked, the seed sown in 
rows a foot apart, and after it is covered the soil is well trodden with 
the feet and raked over. The trampling of the feet makes it quite 
hard, and is considered to do good by preventing progress of the 
Maggot." Mr. Wilkie mentions the Onion Maggot as having done 
considerable • damage at Ardkinglas, Argyllshire; but that after 
mixing a good glassful of paraffin oil with about six gallons of water 
* The power of the Maggot to travel from one bulb to another deserves more 
consideration than is usually given to it. This point is not mentioned, as far as I 
am aware, in the life-histories; but from my own observations I believe the Onion 
Orub has full power if food runs short in one spot to remove to a neighbouring 
bulb.— Ed. 
