ONION FLY. 159 



pup?e should be left down till dead. If ground with buried pupfe 

 that naturally hatch in April is turned up again in March, no 

 good will have been done by burying them. 



For measures directly protecting the hulh from attack. — It was 

 plain that the flies must lay their eggs somewhere, and if they 

 could not get at the right place (for them) to lay them in, the 

 eggs must be dropped where they either would not hatch or 

 the maggots would perish. I found the eggs in such cases 

 were laid too far up the leafage of the Onions to do any 

 mischief, or were merely dropped on the ground. During two 

 seasons I experimented on the effect of covering Onion-bulbs 

 up to the neck, or rather higher, with earth, and the plan 

 answered so well that I tried on a more definite plan and with 

 great success. 



During January in 1884 I had a trench dug as if for 

 Celery, and in this good manure was laid and covered over 

 with a few inches of earth. At the usual time in the spring I 

 sowed Onions along the trench, disturbing the soil as little as 

 possible, and also sowed Onions in the bed alongside. As the 

 plants grew I had the earth from the sides of the trench 

 gradually worked down upon them, which kept the bulbs 

 fairly buried throughout the season, and also kept down the 

 weeds. The row of Onions next the trench was also kept 

 more or less covered, as the earth lay conveniently for 

 spreading over the bulbs. 



The Onions in the trench throve remarkably well, and 

 throughout the season there was hardly any attack of Onion 

 Fly on these ; those by them did well, but not so markedly ; 

 and on Sept. 10th, when the crop was raised, those from the 

 trench gave a yield of sound and good bulbs, many of them 

 very fine. Samples of these which I forwarded to the 

 inspection of Mr. J. Chalmers Morton, Ed. of the * Agricultural 

 Gazette,' were pronounced by him to be satisfactory, and my 

 plan has since been tried with success in Canada. 



There might be difficulties in carrying out this plan on a 

 large scale, but in many cases it would answer well to have 

 beds slightly ridged for Onion growing. Thus the earth would 

 not fall away and leave the bulbs exposed ; the weeds amongst 

 the Onions would be smothered. Also, when thinned (which 

 is an especially dangerous time relatively to Onion Fly attack) 

 the plants could be firmly fixed by the earth being hoed down 

 on them, instead of being thrown open to attack by being 

 loosened in the ground just when the smell of the bruised 

 plants may be presumed especially to attract the fly. 



The maggot infested Onions may be known by their leaves 

 fading and turning yellow, whilst the inside of the bulb 

 becomes decayed. 



