INSECTS INJURIOUS TO CUCUMBER, MELON, ETC. 165 



The Melon Aphis (Aphis gossypii (ilov.)-— The melon aphis 

 or "louse" may serve as typical of the plant-lice. It is in some 

 seasons one of tlie most important enemies of melons and some 

 other crops, and is injurious like other aphides by piercing 

 the plants affected with its beak and thus sapping their vitality. 

 It occurs from early spring to late in autumn on cucurbits of 

 all kinds, many other crops and weeds of great variety and 

 in its seasons of abundance, notably following springs that 

 are cool and rainy, it frequently does very serious damage, 

 causing the leaves attacked to curl, shrivel and lose color, inter- 

 fering with the ultimate development of the fruit, if not kill- 

 ing the plants outright. 



The melon aphis is variable dark green in color and of 

 sluggish habit. ^ The principal stages are illustrated in 

 figure 47. Winter eggs have been found on strawberry and 

 purslane. This species is of unknown but perhaps tropical 

 origin, since it shows a decided preference for, and has done 

 most injury to, plants of a tropical nature, such as cucurbits, 

 cotton and orange. 



METHODS OF CONTROL 



The severe losses occasioned by this insect in seasons when 

 it multiplies in unusual numbers could be largely mitigated 

 and, in small areas, almost entirely prevented if the employ- 

 ment of methods of destruction were begun upon its first ap- 

 pearance. First of all, it is necessary to familiarize oneself with 

 the insect and the condition of the plants by which its pres- 

 ence is manifest that measures of control may be instituted 

 liefore it is too late. In ordinary seasons it is controlled by 

 natural elements and insect enemies alone, and when the 

 weather is unfavorable to the development of the latter the 

 grower should be on the alert. 



■ 1 The only other cucurbit louse with which it is apt to be confused is the 

 squash aphis {Nectarophora cucurbitic MuUUeton), a much larger species and 

 more uniformly paler green in color. 



