1052 EXPERIMENT STATION RECORD. 



older cotton-growing States and prevails over considerable portions of 

 North Carolina, South Carolina, Georgia, Alabama, and Mississippi. 

 It is usually worse on old, worn, sandy lands, but may appear on any 

 soil in which the humus has become exhausted. Plants on low, wet 

 lands and seepy hillsides are also subject to the disease, while sporadic 

 cases may be found in almost any soil under favorable conditions. 



Experiments with this disease have been conducted at the station 

 farm and also in cooperation with a number of planters, in which the 

 efficacy of improving the soil by means of potash fertilizers has been 

 tested with good results. From the different experiments it seems that 

 by ameliorating these conditions, giving better drainage, incorporating 

 more vegetable matter in the soil and supplying abundant plant food 

 in complete fertilizers, especially those rich in potash, the disease may 

 be almost wholly prevented. The author believes that by a greater 

 diversification, so that crops will be grown in rotation, the condition 

 of the soil will be improved to such an extent that the disease will be 

 no longer troublesome. 



The potato disease, H. M. Ward (Ann. Bot., 12 (1898), No. 18, pp. 

 561-561). — A potato disease which is not due to Phytophthora, and 

 which has often been ascribed to bacteria, has been recognized here and 

 therein England for a number of years, and for 2 years the author has 

 conducted investigations on it. On the diseased plants the shoots turn 

 yellow and die prematurely during the summer before the tubers have 

 become anything like full grown. The disease starts from below and 

 not from the leaves. The roots are few and soon rot away. The tubers 

 do not mature and frequently rot in the ground. The leaves turn yel- 

 low and wither on the stems, with symptoms of premature wilting, and 

 often remain hanging on the yellow, glassy-looking, but still living 

 stems. In severe cases, especially in wet places, the stems and roots 

 may all be rotted by the end of July, and casual observation would 

 attribute as a cause the presence of Phytophthora. In mild cases the 

 symptoms are not so obvious and the disease may be complicated by 

 the presence of the Phytophthora fungus. In advanced stages of the 

 disease the stems either dry up or rot on the wet ground. Very often 

 bacteria gain access to the tissue at a comparatively early stage. 



Sections across the lower part of the stem show one or more of the 

 vascular bundles yellowish brown and the principal vessels contain 

 branched septate hyphse. In several cases these hyplnc have been 

 traced from the leaves through every internode of the stem through 

 the roots and into the tubers. In advanced cases the brown vessels 

 are stopped with a yellowish gumlike substance. Those tubers which 

 are not attacked while still very young, but which have begun to fill 

 with starch, may offer considerable resistence to the invasion of the 

 fungus; but eventually the vascular strands show the red or yellowish 

 brown color, and in many cases the ripened tubers are to all appear- 

 ances sound except for microscopic reddish spots at the point of 



