DISEASES OF PLANTS. 643 



A large number of inoculation experiments were made and field observations 

 taken, which indicate that V. gecevi develops and acts as an obligate saprophyte, 

 and can not, therefore, be considered as the cause of the disease. Inoculations 

 with an unknown fungus, or possibly with several fungi, produced good in- 

 fections resulting in diseased ears, but these are to be the subject of further 

 study. It is considered that C. gecevi is of economic significance only in that 

 it destroys the cob tissue as a saprophyte, and that its effect on the kernels 

 is rather limited when compared with the injury caused by Diplodia, Fusarium, 

 and other fungi. 



Hot water treatment for cotton anthracnose, H. W. Barre and W. B. Axill 

 {Science, n. ser., 40 (1914), No. 1020, pp. 109, 110). — A preliminary report is 

 given of experiments to test the effect of hot water at different temperatures 

 on the anthracnose fungus and on cotton seed, the object being to determine 

 whether the fungus could be killed without injury to the seed. 



As a result of the test it was found that cotton seed can remain at 70° C. 

 for 15 minutes without injury to germination. This temperature seems to be 

 destructive to the fungus, as seed so treated has been germinated free from 

 disease, while an average of 22 per cent of the seedlings in the checks from the 

 same lot of seed were diseased. 



Two fields of cotton on the Clemson College farm have been planted with seed 

 so treated and are under observation to determine the ultimate effect of the 

 treatment. 



Disease resistance of potatoes, W. Stuart {Vermont Hta. Bui. 119 {1914), 

 pp. 147-183, pis. 4, figs. 7). — In continuation of previous reports on investiga- 

 tions carried on at the Vermont Station on disease resistance of potatoes 

 (E. S. R., 17, p. 1078), the author gives a final account of his investigations on 

 varietal resistance of potatoes to the attacks of the early blight {Altcrnaria 

 solani), late blight {Phytophthora infestans) , and the scab {Oospora scabies). 



Tests of a large number of varieties of potatoes of American and European 

 origin have been conducted. The varieties which showed the greatest resistance 

 or fi'eedom from early blight were, with few exceptions, of foreign origin. The 

 resistant foreign varieties were almost without exception of little commercial 

 value, as they were usually light yielders and rather poor in quality. The 

 author considers the value of disease resistance in potatoes as rather prob- 

 lematical, but suggests that by cros.sing some of the resistant European varie- 

 ties with the more desirable commercial American tyjies some resistant varieties 

 of commercial value might possibly be obtained. 



In testing different varieties for resistance to scab none were found to show 

 markedly resistant qualities when grown on soil well infested with the scab 

 organism. The commonly prevalent idea that russet-skinned varieties do not 

 become scabby was found not to be based on fact, as one of the pronounced 

 russet varieties was very low in the scale of resistance. Some varieties are 

 said to have been found somewhat less subject to scab than others, but it 

 has been impossible to determine whether or not this immunity is inherent. 

 The author believes there is little hope of securing scab-resistant varieties 

 through selection. 



Notes are given on the growing of seedling potatoes, desirable types of pota- 

 toes, and varietal response to Bordeaux mixture. Under the last head the 

 author states that some varieties i-espond better to spraying than others, and 

 that heat, moisture, and sunshine modify the outcome when Bordeaux mix- 

 ture is used. The beneficial effect of Bordeaux mixture is attributed to dimin- 

 ished transpiration, the maintenance of optimum light intensity, and the length- 

 ening of the season of growth. 



