252 
kinds than this one. The first of these diseases which I will 
mention is that commonly known as scab. The name is well 
chosen for the disease is characterized by the rough, scaly appear- 
ance of the tubers. This diseased condition results from the 
presence of a parasitic fungus. 
The potato is not propagated by means of seed but by the 
tubers themselves. If diseased potatoes are planted the result- 
ing crop is sure to be infected. Potato-scab is transmitted through 
the tubers which are used for propagation but may also be trans- 
mitted through the soil. The selection and treatment with for- 
maldehyde of the tubers to be used for planting has been shown 
to be quite effective in controlling this disease. 
One of the most destructive diseases of the potato is the early 
blight which makes its appearance as small, white fungous 
growths on the leaves, often destroying a whole crop before its 
presence has been detected. In places where the potato is largely 
relied upon as an article of food, famine has been known to follow 
the destruction of this disease. The blight not only causes death 
of the plants but brings about rotting of the tubers as we 
raying with proper fungicides* has been found eiectne in 
the control of this disease if taken in time. From a series of 
experiments in New York state spraying has been found to result 
in a saving of more than twenty dollars per acre. If these experi- 
ments were extended throughout the state with equal results 
the saving would amount to $8,000,000 after deducting cost of 
spraying. 
DISEASES OF THE ORANGE. 
The sooty-mould is a fungus which injures the orange to such 
an extent that the losses from this disease in Florida are esti- 
mated at $50,000 annually. This trouble is a combination of an 
insect anda fungus. The insect attacks the orange and the fungus 
appears on the remains of the insect, and together these pests 
have succeeded in disfiguring the orange to such an extent that 
its market value is greatly reduced. 
* Bordeaux mixture, a solution of lime and copper sulphate, is one of the 
best known fungicides. This is sprayed over the es of the plants and 
serves as a preventative against the attacks of fun 
