186 



STATE BOARD OF AGRICULTURE. 



INSECTS AFFECTING THE ONION. 



INSECTS AFFECTING THE BULBS. 



Onion-maggot {Pegomya cepetorum) . 



Besides the barred-winged onion maggot, we have ranging from the 

 Upper Peninsula to Indiana, the common onion-maggot, so well known 

 and so nnich dreaded. This maggot is the offspring of a small fly very 

 ranch like the honse-fly in appearance, except for size, being only about 

 half as large as the house-fly. It is a near relative of the cabbage- 

 maggot and the work of the two is very similar. Unfortunately, some 



Fig. 36. — Onion-maggot, larvae and pupae, enlarged. Original. 



of these onion-maggots pass the winter in the pupal stage and some as 

 adults hidden away in sheltered places. This fact complicates matters 

 somewhat for it necessitates methods of control other than that of 

 merely destroying the pupae by fall plowing. 



The eggs are laid on the young plants early in the spring, and the 

 young maggots api)ear in a short time. When full grown, they go into 

 the soil, change to pupae and later give forth the adult flies. These lay 

 the eggs for succeeding generations, several of which are produced dur- 

 ing the season. In the latter part of the season, the onions are each 

 large enough to harbor a number of maggots, and the infested bulbs 

 which are not killed outright, usually rot after harvest. 



