364 The Spraying of Plants. 



white smut, and the reader is referred to the bulletin mentioned 

 below for detailed descriptions. 



Treatment. All spinach diseases are controlled with difficulty, 

 since the parts attacked by the fungi grow quickly, and they 

 are then used as food. Fungicides would undoubtedly prevent 

 the entrance of the parasites, but the market value of the crop 

 would be lessened to such an extent that the applications can 

 scarcely be advised. The plants might be sprayed with dilute 

 solutions of clear fungicides, but comparatively little has as yet 

 been done in this direction. The destruction of all infested 

 leaves or plants appears to be the most advisable procedure. 



SQUASH. 

 FUNGOUS DISEASES. 



Powdery Mildew. See under MUSKMELON. 



INSECT ENEMIES. 

 See under CUCUMBER. 



STRAWBERRY. 



Leaf Blight; Rust; Sunburn (Sphcerella Fragarice., Sacc.). 

 Description. The foliage of strawberries is subject to the 

 attacks of a fungus which may appear at any time during the 

 growing season. The first symptom of the disease is the for- 

 mation of small purple spots which gradually increase in size 

 until they are from an eighth to a quarter of an inch in 

 diameter (Fig. 89). The purple color is early replaced by a 

 clear, reddish-brown, which becomes of a still lighter shade as 

 the season advances ; the edges of the spots, however, generally 

 remain purple. Badly infested leaves turn dark and are of no 

 value. The fungus passes the winter by means of spores, and 

 by mycelium contained within the leaves. This disease is fre- 

 quently very serious, especially upon certain varieties. 



Treatment. Spraying the plants with the Bordeaux mixture 

 will check the trouble. Applications should be begun as soon 

 as growth starts in spring, and non-bearing plants may be 

 treated throughout the summer, the treatments being made 

 at intervals of three or four weeks. Bearing plantations will 

 derive benefit from a treatment made when growth starts in 



