198 DISEASES AND INSECT ENEMIES. 



the under side of the leaves may be so thoroughly 

 washed that the spiders will have little opportu- 

 nity for development. If this practice is followed 

 throughout the growing season the plants will 

 be able to go into winter quarters practically free 

 from the pest, and will, therefore, require little 

 additional work of this kind during the winter. 

 Whenever it is necessary to spray during the 

 winter, the work must be done on a bright day so 

 that the plants will dry off in a few hours. Never 

 spray later than eleven o'clock, otherwise the 

 crowns will remain wet during the night. 



Green and Brown Aphides, Every violet 

 grower is probably familiar with these insects. 

 Up to six or eight years ago the green aphis 

 was about the only one that ever proved trouble- 

 some. Whether there is more than one species 

 of green aphis which attacks the violet is not 

 known. They can be found nearly always, and 

 it requires only slight neglect for them to soon 

 become exceedingly troublesome. The green 

 aphis, with which every grower is generally 

 familiar, attacks both leaves and flowers, but it is 

 particularly the latter that are likely to show the 

 most serious effects of the pest. Ordinarily, when 

 the leaves are infested the aphis is first found on 

 leaves which have begun to fade. The yellow 

 leaves harbor the insect, but it soon gains sufficient 

 strength, if neglected, to spread to perfectly 

 healthy leaves and from them to the flowers. In 



