130 MARKET GARDENING. 



Some onion growers have found it profitable to drill 

 winter rye in September, and in March plow it down as 

 a green manure, the mass of rye tops and root fibers fur- 

 nishing a vast amount of plant food. Of course, after 

 such a mat of green herbage is plowed under, it is abso- 

 lutely necessary to roll it down hard, otherwise the cavi- 

 ties would cause a drying out of the soil, and the onion 

 plants would suffer more than they gained. 



There are several insects that do damage to the 

 onion crop; one, a large white grub, eating the leaf 

 stalks off beneath the surface of the ground, Manure is 

 the best remedy, stimulating the plants to resist attacks. 

 Another is a louse. The first indication of the presence 

 of the louse is a moldy appearance of the stalks, and, 

 upon examination with a glass, myriads of microscopic 

 insects are revealed; these cause a stunted growth, if 

 not resulting in death. The only remedy is to change 

 the location of the next year's crop. Another destruc- 

 tive insect is a maggot, or small white worm, half 

 to one-third of an inch long, which bores to the heart of 

 the bulb in the latter part of the season. The writer 

 has seen twenty in a single bulb. They are very trouble- 

 some in some years, and salt is believed to be the best 

 remedy. 



A fungus growth known as smut works great injury 

 to the onion, and it sometimes appears on the plants 

 even when but one or two inches high, and covers the 

 green stems with a red and black substance, coming off 

 upon workmen's shoes, implements and tools. The 

 spores may thus be carried from one part of the field to 

 another, or from one patch to another, and spread the 

 disease, as every spore is capable of multiplying itself a 

 thousand times. The only remedy for this disease is to 

 change the location of the crop. All tools which have 

 been used on a smutty onion field must be carefully 

 washed and soaked in hot water, or they may re-establish 

 the disease the succeeding year. 



