CHAPTER XI 



Insects and Diseases Affecting the Onion Crop 



The Onion Maggot (Anthomyia ccparuin) The 

 following is taken from the Connecticut experiment 

 station reports : 



"The adult insect, a small two-winged fly, de- 

 posits its eggs on the lower portion of the young 

 onion plants during the months of April and May. 

 In about a week the eggs give rise to small, whitish 

 grubs or maggots which eat their way into the bulbs, 

 upon which they feed for about two weeks. They 

 then leave the bulb, enter the ground, and change to 

 the pupa condition, from which, in course of time, 

 the adult flies emerge. Occasionally the maggots 

 remain in the bulb and the brown pupae are found 

 in the stored onions. Several broods are produced 

 during the summer. The various stages of develop- 

 ment of the insects are shown in Fig 51. 



"Various methods of destroying this pest have 

 been recommended. Ormerod (in A Text Book of 

 Agricultural Entomology) suggests rotation with 

 some other crop in order that the flies emerging from 

 the pupae which remain in the soil may not find onion 

 plants at hand upon which to deposit their eggs ; 

 earthing the young plants well up above the collar so 

 that the flies are prevented from reaching the bulb; 

 pulling and destroying the plants first affected, by 

 which means the migration of the maggots to sound 

 bulbs is checked ; the avoidance as far as possible of 

 natural manures, in which the larvae of these insects 

 live; or finally the application of lime to the land." 

 E. O. Orpet (in Garden and Forest) recommends the 



