80 DISEASE AND ITS PREVENTION 



tack and live on the leaves of the plant, and the damage they 

 do to the living plant is immense. They eat small holes into 

 the leaves, and, as the leaves are the "lungs" of the plant, it 

 is easily understood why these pests are so injurious to a 

 crop. These beetles are generally found on the under side of 

 the leaf. 



The Empoasca Mali, a small, green hopper, feeds on the 

 under side of the leaf and seems to suck the very life from 

 the plant. As they increase very rapidly, a large amount of 

 vitality is taken from the vine before they are noticed, and, 

 indeed, many crops are destroyed by them. 



Scab is a very common disease of the potato, but is not 

 so serious as generally supposed. There are several causes 

 for the scab: 1st. Alkali in the soil. 2nd. Too much dry 

 manure. 3rd. Poorly drained soil, as the alkali of the soil 

 when too damp will appear on the surface. The best remedy 

 for this disease is the use of the green fertilizer, the acid 

 from which counteracts the effect of the dry manure. When 

 this is persistently carried out, I find that there is no need of 

 "dipping" for scab. However, if it seems best, the grower 

 may soak the seed in a solution of corrosive-sublimate for 

 one and one-half hours, made at the rate of one ounce of 

 powdered corrosive-sublimate to eight gallons of water. As 

 this is a poison, it should be handled with care. It is a 

 stronger poison than the formaldehyde solution, therefore, 

 serves the purpose better. Since this disease stays in the 

 soil, it is best to treat it by the use of green fertilizer. Even 

 if very little disease exists, it is always wise to combine the 

 dry and green fertilizer, and the grower will unusually be 

 successful. 



Wilt is a disease which works in the vine and cannot be 

 reached by spraying. As this disease goes from the stem 

 into the tuber, it is well to harvest before maturity. This 



