583 NEW JERSEY AGRICULTURAL COLLEGE 



Injury Caused. 



There is no stage in the growth of the onion, from the seedling to 

 the seed-bearing hnlb, that is not snbjeet to attaek, but it is the small 

 onions, from one-half to one inch in diameter, that seem to suffer 

 worst. At that stage of their development the amount of tissue is not 

 great; the injury caused by several boring maggots becomes quickly 

 felt, and disease enters at once. A large onion may stand considerable 

 local injury without showing it very much, and may even outgrow a 

 slight attack if there is plenty of stimulating plant food. When decay 

 begins in an onion, be it ever so slight, it is apt to give entrance to a 

 colony of white mites small, spider-like creatures; which live just at 

 the edge of the decayed portion and work ever further forward into the 

 Bounder tissue. Naturally, such a bulb develops little and the plant 

 above ground turns yellow, droops and' dies. 



When the maggots are very numerous and the onions small they 

 may and do go from one bulb to another, and in leaving one bulb the 

 company does not remain together, but may divide into several parties, 

 each taking a different victim. 



The indications of an attaek are seen in the wilting and drooping 

 plants in a row, and as soon as this is noticed active measures are in 

 order. 



Remedial Measures. 



These are of two kinds^ — preventive and destructive. Preventive 

 measures are those which aim to keep off the flies so that they will not 

 lay eggs, because either the odor of the used material is offensive or it 

 is really harmful to the insects. 



Kerosene and sand, at the rate of a pint of kerosene to ten quarts 

 of dry sand, thoroughly mixed, is spread around the plant or along the 

 row, and exercises a deten-ent effect, if it does not also kill young larvfe 

 that may be hatched from eggs already on the plants. This should 

 really be put on before the flies have begun to oviposit. 



Tobacco. — Finely-ground tobacco, or tobacco dust, may be liberally 

 applied along the rows without danger to the plants, but rather to their 

 advantage, because it is a good fertilizer. It should be finely ground, 

 for, as a dust, it is a better repellant, and also more likely to kill any 

 young larvae that may come into contact with it. When it rains the 

 tobacco extract will be more abundant, will go down deeper into the 



