CONTROL OF GARDEN DISEASES AND INSECTS. 19 



Control. — If the plants are grown under glass, plant-lice may be 

 killed by fumigation with a nicotine preparation. The form suitable 

 for this work is paper soaked in nicotine which when lighted causes 

 a smudge. Sprinkling plants with fine tobacco dust is of some 

 value, especially if applied early in the morning when the dew is on. 

 Under large vegetable garden conditions standard 40 per cent nico- 

 tine sulphate gives almost perfect results if properly diluted and 

 applied. It may be used at the rate of 1 teaspoonful of sulphate to 

 1 gallon of water with a 1-inch cube of laundry soap. See " Nico- 

 tine sulphate" (p. 10). 



ANTS. 



Certain species of ants may be found afield from March to October, 

 and often occur in greenhouses and coldframes attacking cabbage and 

 related plants, eggplant, lettuce, beans, parsley, radishes, tomatoes, 

 and peppers. They attack the roots, crown, and lower portions of 

 the stem, and completely destroy young plants. 



Control. — The best remedy is fumigating the nests with carbon 

 disulphid by means of a machine oil can made of metal. Locate the 

 nest and, if possible, the female, or queen. Inject about two or three 

 teaspoonfuls of the liquid into the entrance to the nest, and if 

 liot effective soon repeat the dose a little stronger. Hot water will 

 answer the purpose if the insects are not too abundant. Poisoned 

 baits as for cutworms have been used with good effect. See " Cut- 

 worms " (p. 14). Careful watch should be kept for the appearance 

 of these insects in lawns and elsewhere about the grounds and the 

 nests destroyed. Consult Farmers' Bulletin 740 on '' House Ants." 



ONION THRIPS. 



The onion thrips (fig. 14), incorrectly called " thrip," is micro- 

 scopic in size and is often called the onion louse. It causes an injury 

 somewhat generally known as white blast, white blight, and silver top. 

 It also causes scullions, or thick necks — poorly developed and un- 

 marketable bulbs. This species frequently ruins entire fields of 

 onions. Besides the truck crops mentioned this thrips attacks cauli- 

 flower, cabbages, cucumbers, melons, pumpkins, squashes, parsley, to- 

 matoes, kale, turnips, and seed beets. It is what is known as a general 

 feeder, and it would be easier to mention plants which it does not 

 attack than to list those w^hich it uses as food. 



Control. — Nicotine sulphate, as advised on pages 10 and 11, is used 

 Avith success. 



TARNISHED PLANT-BUG. 



Nearly all vegetables are attacked by the tarnished plant-bug (fig. 

 15), a small leaf-bug measuring about one-fifth of an inch in length 

 when mature. There are five distinct stages, called " nymphs," from 



