niaining green. The leaves were small, wrinkled and thicker than 

 normal. Inoculations with material from this plant on other non- 

 chlorotic plants were without result because of the death of the plants 

 from other diseases. 



Mustard {Brassica spp.). 



The common mustard grown chiefly for the leaves, which are used 

 as greens, is subject to several leaf diseases. The white rust {Albugo 

 Candida [P.] Rouss.) is common, producing numerous white pustules 

 on the lower leaf surfaces. 



A leaf spot {Cercospora hloxami Berk. & Br.) causes the death 

 of the leaves in many cases. The spots are at tirst nearly circular 

 Oiardly spherical as given in one description), white or dull yellow 

 in color and up to half a centimeter in diameter. They very soon 

 run together, however, destroying the leaf. 



Okra (Hibiscus escuhntus). 



Okra was commonly subject to a leaf disease due to (Jercospora 

 liibisci T. & Earle). This fungus did not occur in definite spots, 

 but rather in indefinite sooty patches often confluent on the lower 

 surfaces of the leaves. The leaves were sapped of their vitality, 

 turned yellow and dropped. The result was a tall stem, bare of 

 leaves except at the tip and bearing very little fruit. No experi- 

 ments for control have l)een tried. 



Onion (Allium cepa). 



Onions are raised to a considerable extent in the western part 

 of the Island. Opportunity, however, has not been had to examine 

 any of the plantings. Reference is made by Henricksen (5) to smut 

 (Urocystis cepulae Frost) and to downy mildew (Peronospora Schlei- 

 deniana De Bary) but without definitely reporting them as present 

 in Porto Rico. 



Pea (Pisimi sativum). 



Wherever observed the garden pea has been subject to powdery 

 mildew (Erysiphc polygoni Dc?). This fungus formed a thin gray 

 or wliite coating over leaves and pods, and while it did not actually 

 kill the parts attacked, it cheeked the groAvth and so lessened, the 

 yield. In common with all other powdery mildews collected on va- 

 rious plants, wild and cultivated, the conidial stage only was found. 

 This disease could be readily controlled if necessary by Bordeaux, 



or other fungicide. 



107 



