36 



from its attacks. The most noteworthy of these was the total loss 

 of a crop of cucumbers and tomatoes of an estimated value of four 

 thousand dollars at Pittsfield, Mass., during the Spring of 1901. 

 Dr. H. T. Fernald, who visited these greenhouses about the first of 

 June, found every plant either dead, or nearly so, with none of the 

 crop ready for harvesting. Myriads of the white flies, which were 

 seeking in vain to obtain liquid food from the dried leaves, would 

 fly up in clouds when the plants were disturbed. Many other in- 

 stances of the destruction caused by this insect in this state and 

 elsewhere might be cited, but enough has been said to show that 

 growers of vegetables in greenhouses cannot afford to ignore it when- 

 ever it makes its appearance in noticeable abundance. 



This species of Aleyrodes may also require treatment in con- 

 servatories used for private ornamental or commercial purposes. Its 

 importance here is largely due to its very general feeding habits. 

 Still another class of plants upon which injuries are frequently re- 

 ported are house plants, such as geraniums, heliotrope, etc. 



Cucumbers and tomatoes are among the most delicate of the 

 plants which are liable to require treatment from the attacks of this 

 insect, as well as those upon which the attack is most liable to result 

 in serious financial loss. The treatment of these two plants has 

 therefore been given special prominence in this paper. The general 

 principles for the treatment of plants in florists' establishments are 

 the same as for the forcing pit, while as for the treatment of house 

 plants they are so comparatively unimportant that but a few words 

 need be said. 



PREVENTIVES. 



In dealing with this insect, preventives are of prime import- 

 ance. Owners of greenhouses which are subject to its attacks can 

 well afford to insure their plants against total or partial destruction 

 by a very small expenditure of time and money. The axiom, an 

 ounce of prevention is worth a pound of cure, applies here as well as 

 to all other human troubles. Moreover, the cure, unless one is con- 

 stantly on the lookout for insect pests, is in this case liable to be 

 applied when too late and the destruction has been already accom- 

 plished. 



