259 



We have, however, a Southern potato blight that' is often 

 very destructive. It manifests itself by the sudden wilting 

 of the tops about the time the young potatoes are forming 

 or perhaps after they are nearly grown. On ciitting open 

 the freshly wilted stems a spot will be found near the sur- 

 face of the ground where the substance of the stalk looks 

 clear and watery much as in the "water core"- 6i' certain 

 apples. This watery portion is found to be swaVming with 

 bacteria and there is little question but that they are the 

 direct cause of the disease. At first the yOung potatoes will 

 still be quite sound but the disease soon rieaclies them 

 through the stem and causes them to rot: Wheii seemingly 

 sound potatoes from a diseased vine are cut opie-n a brown 

 line can often be traced under the skin showing-fchat'the dis- 

 ease has already reached them. Such potatoes vVill not keep 

 but will rot quickly, and if stored with others the rot soon 

 spreads throughout the mass, causing great loss. This dis- 

 ease seems to live in the soil from one crop t<i the next, so 

 that it is unsafe to plant potatoes the following- year on land 

 where the disease has appeared. The same, oi- lat least a 

 very similar disease attacks tomatoes, egg plants and pep- 

 pers, so that these crops should not follow blighted pota- 

 toes. ' 



No remedy is known except to avoid planting' on infected 

 land and to practice rotation of crops. •' ' 



Potato Scab. — The black roughened or sunken patches 

 often seen on potato tubers are caused by an obscure fungus 

 ( Oospora scabies). The same fungus attacks beets. It seems 

 to be able to live as a saprophyte on the vegetable' matter in 

 rich soils, so that when the soil is once infected by planting 

 scabby seed it is unsafe to plant it again in potatoes for some 

 years. No known treatment will prevent the Scab on such 

 land. On clean land, treating the seed with corrosive subli- 

 mate will entirely prevent the disease even if scabby seed is 

 used. Of course clean seed should always be used when 

 possible. For this treatment dissolve two and one-half 

 ounces of corrosive sublimate in two gallons of hot water in 

 a tub or barrel. After standing until all is dissolved add 



