INSECTS ATTACKING CUCURBITACEOUS PLANTS. 8 13 



shining, and are laid in more or less regular rows in masses con- 

 taining between twenty and forty each, as shown in Figure 14 

 and on Plate LII a. The young nymphs hatching from the eggs 

 are ash-gray in color and pass through five distinct stages before 

 reaching maturity, during which time they are found underneath 

 the^ leaves, getting their nourishment from the sap. The nymphs 

 and adults are shown on Plates LII and LIII. See also Figures 

 15 and 16. 



The adults are hard to kill, but the young nymphs are quite 

 susceptible to applications of kerosene emulsion. Hand-picking 

 and the use of plant protectors such as are used against the striped 

 cucumber beetle are to be advised. Above all, clean-cultural 

 method^, such as burning the old vines after the crop is harvested, 

 are essential. 



The Melon Aphis or Plant Louse. 

 Aphis gossypii Glover. 



This is really one of the worst insect enemies of this class of 

 crops. It is nearly always present, and being on the under sur- 

 face of the leaves, where it sucks the sap, it escapes notice until 

 the leaves begin to curl on account of it. On account of its posi- 

 tion and the curling of the leaf, it is extremely difficult to strike 

 it with a spray, though this can be done with the proper outfit. 

 The melon aphis is much more injurious to cucumbers and melons 

 than to squashes and pumpkins. When first born, the insects 

 are yellowish green, but they soon take on a darker tinge and 

 finally become brown. This aphis is pronounced by Chittenden* 

 the most injurious plant louse in this country, and it attacks a 

 great variety of plants, among which are cotton and several kinds 

 of vegetables, in addition to the melon and cucumber. Besides 

 these, it is found upon, and is doubtless able to subsist upbn, a 

 large number of common weeds. The entire life history of this 

 insect is not known. The species is able to multiply so rapidly 

 that plants are often very seriously injured in a short time, and 

 late in summer it usually disappears very suddenly. See 

 Figure 17. 



Our common lady-beetles and syrphus flies prey upon the melon 



aphis. 

 * Circular 80, Bur. of Entomology, U. S. Dept. of Agriculture, 1906. 



