326 The Spraying of Plants. 



It covers the foliage with a white, downy layer, which almost 

 entirely obscures the green color of the leaves and steins. 

 Later, small black dots appear, these being the fruiting bodies 

 of the fungus. 



Treatment. The disease could undoubtedly be easily checked 

 by means of the copper sprays ; but the foliage of these plants 

 is of such a character that liquids do not readily adhere. Soap 

 will assist in overcoming this difficulty if it is added to the 

 liquids. Another line of treatment which might be followed 

 by good results is to apply powders to the vines while they 

 are wet with dew. Fostite should prove of value for this pur- 

 pose. 



Rust. This is the same disease which has been discussed 

 under BEAN. It is rarely serious. 



INSECT ENEMIES. 



Weevil ; Pea-bug (Bruchus Pisi, Linn.). Description. The 

 adult is a dirty-black beetle having white markings on. the wing 

 covers, and a T-shaped mark of the same color at the extremity 

 of the abdomen. The insect is scarcely three-sixteenths of an 

 inch long. The winter is generally passed in the adult stage, 

 the beetles mostly appearing in the spring. Eggs are laid while 

 the young pods are forming, and the larvae enter the growing- 

 peas, upon which they feed, rarely injuring the germ, how- 

 ever, although the seed is considerably weakened. The insects 

 pupate within the peas, and soon afterward the adult appears, 

 although it does not leave the peas, as a rule, until the following 

 spring. 



Treatment. No practicable method has yet been found by 

 means of which the beetle can be prevented from laying its 

 eggs in the young pods. The practice commonly followed is to 

 treat the peas, after harvesting, with the bisulphide of carbon. 

 Two or three treatments at intervals of three or four weeks 

 will be found sufficient to exterminate the pest. Another 

 method of destroying the insects is to subject the peas to a 

 temperature of 145 F. for about an hour. If this is done as 

 soon as the peas are ripe, the larvae, which are then practically 

 grown, will succumb, and the germinating qualities of the seed 

 will not be injured. The bean-weevil may be successfully 

 treated in the same manner. 



