INSECTS AND DISEASES 50 



oughly that the application will reach the worm 

 feeding at the root stalk or bulb. 



When the plants are in a hotbed, maggots can be 

 destroyed by inserting bisulphid of carbon into the 

 soil. Professor Bailey recommends to puddle the 

 plants when transplanting in a puddle to which sulphur 

 has been added, and sprinkle sulphur about the plants 

 after they are set. Of course all infested plants should 

 be pulled up and burned at once. 



The Onion Thrip {Thrips tabaci) — Onion grow- 

 ers sometimes find their onions affected in a manner 

 that they are undecided whether to lay the blame on 

 insects or disease. When a plant appears as shown 

 in Fig 52, most people will say that it has been struck 

 by blight. The truth is, however, that the enemy is 

 a small insect or midge. The illustration, taken from 

 a bulletin of the Ohio station, shows a plant that is 

 very seriously affected, and totally crippled, by thrips. 

 The effects of the attacks appear as a white blast, 

 and may be easily mistaken for a diseased condition. 

 We may not have much to fear from this enemy in 

 a wet season. It is the dry season which is liable to 

 bring us the attacks of thrips. The Florida agricul- 

 tural experiment station reports that the insect was 

 first noticed there about the middle of April in 1897, 

 infesting onions at the station gardens, and that the 

 insects were destructive until about July i, when they 

 gradually disappeared. I quote as follows from 

 Bulletin 46 : 



"In 1898, the insect was observed April 28^ to be 

 quite abundant on onions in the horticultural depart- 

 ment, and some days later, Professor Rolfs called 

 my attention to its occurrence on cabbage and cauli- 

 flower. To these plants it proved quite destructive 

 during May, and the first two weeks of June. By 

 the last of June, the insects were becoming very 



