The Cucumher ' 385 



Mosaic. — AfEected fruits may lave raised areas and present 

 a mottled appearance due to tlie presence of alternate green 

 and yellow places. Leaves may exhibit a similar mottling. 

 Control: The control measures recommended for bacterial 

 wilt will aid in keeping this disease in check, as the virus 

 is apparently distributed by insects. ' 



Downy Mildew (Plasmdpdra cuhenais). — Somewhat angu- 

 lar yellowish spots appear and under favorable conditions 

 spread rapidly, r^ulting in the death and drying of affected 

 leaves. Control: Spraying with bordeaux mixture, if begun 

 as soon as runners begin to form and repeated every week or 

 ten days throughout the season, will afford good control. 



Angulab leaf-^pot (Bacterium lachrymans) . — This dis- 

 ease is characterized by the production on the leaves of sharply 

 angular spots bordered by the larger veinlets. The spots are 

 at first water-soaked, later turning brown. Dead parts in old 

 leaves may break away, causing a somewhat ragged appear- 

 ance. The disease is evident on the stem as elongated lesions. 

 Small water-soaked spots, circular and with white centei's, 

 may appear on the fruits. Control: Seed treatment with 

 corrosive sublimate 1-1,000 for five minutes has been recom- 

 mended. Spjaying with bordeaux mixture as recommended 

 for other cucumber diseases will hold this leaf-spot in check. 



Antheacnose (Oolletotriclvum lagenarium). — See Water- 

 melon, page 296. 



Striped cucumber beetle (Diabrotioa vittata). — A small 

 yellow black-striped beetle, % in. long, that attacks cucumber 

 plants when they first come up, devouring the leaves and eat- 

 ing holes in the stem. The eggs are laid on the ground. 

 The larva is a slender white grub, ^ in. jlong, that burrows 

 in the roots, sometimes causing the plants to wither and die. 

 Control: In the home garden the plants may be protected 

 by cheesecloth or mosquito-netting screens. In the field, spray 

 the plants as soon as they come up with arsenate of lead 

 (paste), 4 lbs. in 50 gals, of water. Although the beetles 

 will not eat much of the poison, it serves to drive them 

 away. It is better to use arsenate of lead for this purpose 



