ONIONS 325 



turned until dry enough to thresh. Cleaning is done by repeated 

 winnowing and by washing in buckets or tubs to separate the light 

 seed and chaff that the winnowing fails to remove. The seed 

 must be thoroughly dried and stored in a place free from exces- 

 sive moisture. 



Insects and diseases. Onion maggot (Phorbia cepanini). This is 

 one of the most destructive insect enemies of this vegetable in 

 both Europe and America. The eggs are deposited on the plants 

 near the ground, and require about a week to hatch. After the 

 eggs have hatched, the larvae burrow into the bulbs and remain 

 for about two weeks, when they emerge, pupate in the ground, 

 and the adult insects which develop deposit their eggs for another 

 generation. The larvae cause the plants to turn yellow, wither, 

 and finally die before the bulbs have matured. 



Such preventive measures and remedies as the following have 

 been suggested : the application of unleached wood ashes and 

 charcoal spread over the beds ; the use of gas lime between the 

 rows ; the sowing of potash salts ; rolling the beds before sowing ; 

 growing the bulbs in trenches ; drawing the earth about the plants 

 as they grow. Planting in a new location each year is perhaps the 

 most effective preventive. 



Carbolic-acid emulsion has been found by the New York Cornell 

 Experiment Station to be an effective remedy. The emulsion is 

 made by dissolving I pound of hard soap or I quart of soft soap 

 in I gallon of boiling water, to which I pint of crude carbolic acid 

 is added, the whole being stirred into an emulsion. One pint of 

 this added to 30 quarts of water and poured around the bases of 

 the plants, about 4 ounces per plant at each application, beginning 

 when the plants are set out and repeated every week or ten days 

 until the last of May, will prove effective. To bring about the 

 best results, some of the earth should be removed from about the 

 plants before pouring on the emulsion. Such treatments, however, 

 are out of the question in commercial practice. 



Onion thrips. This is one of the insects that secure their nour- 

 ishment by sucking the juices of the plants which they attack. The 

 thrips is very troublesome to onions that have suffered a check to 

 their growth. The insect attacks the leaves, causing them to assume 

 a dull gray or dirty appearance, which afterwards turns to brownish 



