Cucumber. 283 



Powdery Mildew (Plasmopara Cubensis, B. & C. ) See under 

 MUSKMELON. 



INSECT ENEMIES. 



Melon-louse (Aphis Cucumeris, Forbes). Description. This 

 louse attacks cucurbitaceous plants, especially cucumbers and 

 muskmelon vines, about the middle of June. The affected 

 leaves curl, the edges turning downward and inward, and thus 

 affording protection to the insects, which propagate at a very 

 rapid rate. Large quantities of honey-dew are excreted, and 

 in this material a fungus grows which blackens the vines in a 

 manner similar to that which occurs on pear trees attacked by 

 the psylla. Badly infested plants die. 



Treatment. The vines should be closely watched during the 

 season, and the curling leaves should be removed and destroyed 

 with the insects upon them. Applications of the Hubbard-Riley 

 kerosene emulsion, diluted about fifteen times, made to the 

 under side of the leaves will be of value; or whale-oil soap, 

 used at the rate of one pound to six gallons of water and simi- 

 larly applied, will also prove effective. The insect is a difficult 

 one to keep under control. 



Melon-worm (Eudioptis hyalinata, Linn.). Description. The 

 adult insect is a moth of bright, pearly-white color. A dark 

 border extends along the front and outer edges of the fore 

 wings, and along the lateral margin of the hind wings. The 

 larvae are a little over an inch in length, yellowish-green in 

 color, a few hairs being scattered over the body. They feed 

 upon the foliage and fruit of melons, cucumbers, squashes, etc., 

 being particularly destructive in the southern states. 



Treatment. Hellebore may be used successfully ; but the 

 arsenites offer perhaps the best means of destroying the insects. 



Spotted Cucumber-beetle; Southern Corn Root-worm (Diabro- 

 tica, 12-punctata, Oliv.). Description. The adult insect is a 

 beetle about one-fourth of an inch in length. It is yellow in 

 color, but has twelve black spots upon its back, as its name 

 implies. The winter is passed in the mature stage. The eggs 

 are laid in spring about the roots of cucumbers, squashes, etc., 

 and in the South corn is very commonly selected. The eggs 

 produce a slender, dirty-white worm, which is about half an 

 inch in length when full grown. There are two broods each 



