BUREAU OF PLANT INDUSTRY. 133 



this cotton, and the work is being extended to Arkansas and other 

 Northern Stales. It has been found (hat the Dixie cotton seed has a 

 higher oil content than other varieties tested. The supply of seed 

 of this variety has been greatly increased but is yet insufficient to 

 meet the demand for it. The new, early, big-boiled, wilt-resistant 

 hybrids continue to show great promise, being earlier than the Dixie, 

 as well as heavier yielders. 



POTATO DISEASES. 



The potato tuber rots, particularly troublesome in the Western 

 States, have been worked out and found to be due to several fungi 

 producing different types of decay hitherto confused. Remedial 

 measures have been demonstrated to be practicable. In irrigated 

 regions potatoes should not be planted on newly reclaimed land until 

 crops of alfalfa and grain have preceded them. Careful selection of 

 seed, the use of a seed plat, and seed disinfection are advised. Im- 

 proved methods of seed treatment have been worked out. Careful 

 handling and cool storage have controlled powdery dry-rot. The 

 potato " leak " of California has been controlled in car-lot shipments 

 by sorting out all bruised and wounded tubers. 



The continued shortage of potash is affecting the crop in portions 

 of the Atlantic States. The appearance of the plants suffering from 

 potash hunger is so characteristic that the deficient fields may be 

 recognized and the next crop safeguarded by potash fertilizer, stable 

 manure, or compost. 



CUCUMBER DISEASES. 



In the investigation of cucumber diseases important discoveries 

 have been made. The so-called " white pickle " has been shown to 

 be a mosaic disease, transmitted chiefly by insects, and its control 

 therefore, if accomplished, will be through the extermination of 

 infected insects. It has also been determined that both the anthrac- 

 nose and the angular leaf-spot of cucumbers are transmitted in 

 the seed. A special study of the process of seed saving in relation 

 to this factor was carried on last season. Various methods of seed 

 treatment were tested to determine their effect upon germination and 

 their value as disinfectants. 



WATERMELON DISEASES. 



Further experiments on the control of stem-end rot of water- 

 melons have been very successful. It has been found that losses in 

 transit due to the appearance of this disease can be largely prevented 

 by the application of a disinfectant paste to the cut stems of the 

 watermelons before shipment. Many carloads have been treated in 

 this manner, and the growers in the sections where demonstrations 

 have been made are rapidly putting the method into practice, with 

 great reductions in loss in treated cars as compared with untreated 

 cars. Many buyers are now demanding that melons be treated, and 

 are in some instances paying higher prices for treated lots. Water- 

 melon anthracnose, another serious disease in many sections, has been 

 successfully controlled by spraying with Bordeaux mixture. 



