202 Diseases of Truck Crops 



DISEASES OF THE CAULIFLOWER (Brassica 

 oleracea var. botrytis) 



The cauliflower with few exceptions is subject to 

 the same diseases as the cabbage. For a discussion 

 of black rot, see p. 190; soft rot, p. 192, club root, 

 p. 1 86, and drop, p. 143. 



BACTERIAL LEAF SPOT 

 Caused by Pseudomonas maculicola McC. 



Bacterial leaf spot was first studied and described 

 by McCulloch 1 who found it to be prevalent in south- 

 eastern Virginia and in Florida. The disease un- 

 doubtedly must have a wider and more geographical 

 distribution than is generally known. The author 

 has met with this disease in New Jersey, Delaware, 

 Maryland, and Texas. 



Symptoms. The disease is characterized by numer- 

 ous small brownish to purple-gray spots (fig. 33 a). 

 When the small spots coalesce, the entire leaf surface 

 may be involved. Practically all parts of the leaves 

 are affected. When the midribs and veins are at- 

 tacked, the tissue becomes shrunken, and the leaves 

 have a puckered appearance. In early stages of 

 infection, the spots on the leaves are watersoaked, 

 later becoming dry and dark to purplish gray. In 

 transmitted light the centers of the spots are thin, 

 almost colorless, and surrounded by a dark border. 



1 McCulloch, Lucia, U. S. Dept. of Agr. Bur. PI. lad. Bui. 225 : 7- 

 15, 1911. 



