4 BULLETIN 1116, V. S. DEPARTMENT OF AGPJCULTUEE. 



him and with rice seed grown in the Southern States (PL I). How- 

 ever, at least three strains of this fungus were found, basing the 

 difference on size of the sclerotia and the color of pigment produced 

 in certain types of media. 



One strain isolated from rice leaves was almost free from pigment 

 in culture; another strain from leaves produced a small quantity of 

 pinkish pigment on most media. One form from rice seed produced 

 an abundance of pinkish pigment, while a second form seemed to 

 be identical with one of the strains from leaves in that it produced 

 a small quantity of pigment. On synthetic agar the mycehum of all 

 forms developed for the most part beneath the surface of the medium, 

 and the size and number of sclerotia produced correlated closely with 

 the pigmentation on other media. The size of sclerotia was directly 

 proportional to the quantity of pigmentation, and the number was 

 inversely proportional. In addition to this sclerotial fungus, a 

 number of fungi were found in the seed which were capable of causing 

 staining and decay and a certain percentage of seedling injury. 

 Among these were some of the common rice parasites, Piricularia and 

 Helminthosporium. Other forms present were species of Epicoccurn, 

 Penicillium, Aspergillus, and Eusarium. Other genera occurred 

 rarely and were not given much consideration. 



These fungi, no doubt, enter the kernels to a certain extent before 

 they are mature. The spores probably lodge between the glumes 

 at flowering time. Panicles of Honduras rice were collected about the 

 time they were fully mature and were thoroughly dried at once. 

 Seeds from these, 62 in number, were dehulled and treated for three 

 minutes with 70 per cent alcohol. They were then immersed in 

 mercuric-chlorid solution (1 to 1,000) for 10 minutes and placed in 

 tubes of sterile agar and incubated at room temperature. Fungi 

 were found to be present in 27 of these seeds. The percentage of 

 infection was hardly as high as in seed collected from the same field 

 after the rice had stood in the shock through a rainy season. 



The infection spreads, no doubt, if the rice remains shocked under 

 warm, moist conditions. At the same time the infections already 

 present have a tendency to spread through the kernels. Under 

 such conditions sclerotia of the sclerotial t3rpe of organism are formed 

 in the glumes and on the surface of the kernels. Such infected 

 kernels often are shriveled and very brittle. When conditions are 

 very humid this fiuigus causes the kernels to become much enlarged 

 and very irregular in shape, with sclerotia resembling those produced 

 by ergot in grain. These distorted kernels are almost black in color 

 (Pis. II and III) , and the tissues are filled with a sclerotial develop- 

 ment. Where the other fungi mentioned are present the kernels 

 have the brown flecks, and the decayed tissue is a uniform brownish 



