

Fighting the Fungi in their Winter Quarters. 397 



Dry Rot of Potatoes. — Have you examined your seed potatoes to 

 see how they are keeping? Perhaps you have noticed in the potatoes 

 you are using that some of them show when cut across the stem end a 

 circle of brown or black spots just a little way under the skin. This 

 is the work of the " dry rot " fungus. It is a soil fungus that gets into 

 the tuber through the stem. It usually does little damage during the 

 growing season but spreads in the sap tubes of the tubers after they are 

 stored. At first it does not show on the outside of the potatoes but after 

 a time if the store room is moist and warm the stem end of the tuber 

 begins to shrivel and turn brown with a dry rot. Many white or greenish- 

 white warts burst through the diseased surface. These are the spore 

 masses of the fungus. The entire rotted surface may become covered 

 with a white, moldy growth. The fungus spreads from these rotted 

 tubers to the adjoining healthy ones. The rotted potatoes should be 

 sorted out and destroyed at once. The sound ones should be disposed 

 of as soon as possible as they are unfit to plant. Alany of them are sure 

 to have the fungus in the sap tubes and while they will not be unfit for 

 food should not be planted. If these diseased tubers are planted they will 

 cause the next crop to suffer from the fungus and what is worse, will 

 infect the land so that it will be unfit to plant potatoes for several years. 

 Get seed that does not show this dry rot and plant it on clean land, land 

 that has not grown potatoes for several seasons. There is no seed treat- 

 ment that will prevent this disease. The fungus is inside beyond reach of 

 poisons. If you are buying your seed potatoes inspect them carefully 

 to see that you do not get the pest on your farm. It is much easier to 

 keep it off the land than it is to rid the place of it once you get it. The 

 constant or frequent planting of potatoes on the same land is very favor- 

 able to the increase of this disease. A four or five years' rotation should 

 be followed. 



Black Rot of Cabbage. — This disease is often quite destructive in 

 sections where cabbage is grown on a commercial scale. It is known 

 by the wilting and yellowing of the leaves which soon become dry and 

 papery. The veins when the leaf is held to the light show black. The 

 disease is caused by bacteria that get into the leaves through the water 

 pores at the edge, travels down through the tubes in the veins stopping 

 them up and causing the wilting of the leaf. It causes the leaves to 

 die and drop from the stalk leaving only a small tuft or head at the top. 

 This disease is sometimes followed by another which causes the head 

 to become soft and rotten with a foul odor. This is known among growers 

 as " Stump Rot," on account of the fact that the head becomes loosened 

 and may be lifted from the stalk. It has been found that the bacteria 

 that cause the Black Rot are often carried over on the cabbage seed. 



