Circular No. 19. Novkmher, 190S. 



MASSACHUSETTS AGRICULTURAL EXPERIMENT STATION. 



A.MHERST. 



THE WHITE FLY. 

 V>y C. E. Hood, I). S. 



This insect has become a very serious pest in greenhouses, and 

 were it not possible to hold it in check, the crop each winter where 

 it is present would be a total failure. It is not confined to the 

 tomato alone but also attacks cucumbers, lettuce, melons, tobacco, 

 geraniums and many other plants, and is not only important in hot 

 houses, but in summer does considerable damage out of doors. 



The egg of the white fly is oval in shape, somewhat pointed at one 

 end. The rounded end of the egg is fastened to the leaf so the egg 

 will hang down if the leaf is horizontal. In about two weeks these 

 eggs hatch into tiny young, which crawl around for a few hours and 

 then insert their beaks into the leaf and suck the juices until full 

 grown, which is about two weeks from the time they hatch. After 

 passing through the pupa stage, a T shaped opening is made in the 

 back and the adult fly emerges. The mouth parts of both the young 

 and fly are formed for sucking. They push their beaks into the 

 succulent portions of the leaf and extract the juices, and as a result, 

 the leaf soon dies and falls to the ground. Most of the harm, how- 

 ever, seems to be done by the young. Some time after the leaves 

 are infested, there is a sticky substance exuded over the leaf, on 

 which a black fungus grows, which soon covers the entire under 

 surface of the leaf, making it sooty in appearance. 



REMEDIES. 



There are two methods of attacking this insect, i. Fumigating 

 with hydrocyanic acid gas. 2. Spraying with contact insecticides, 

 such as a solution of Bowker's Tree Soap. 



Fumigation is the most successful and most satisfactory method 

 for the control of this insect that has as yet been discovered, though 

 the gas produced is a deadly poison and extreme caution must be 

 exercised in its use. It is essential in fumigating that the cubic con- 

 tents or amount of space in the house be known, that the right 

 amount of chemicals to use may be determined. The best propor- 

 tions to use of the cyanide, sulphuiic acid and water are : — 



1 part cyanide of potassium {()S''/( or gc/^). 



2 parts commercial sulphuric acid. 

 4 parts water. 



