AGRICULTURAL EXPERIMENT STATION. 113 



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conditions continue tiiis warty tissue begins to deca}' and a scab is 

 formed. 



The loose tissues which compose these warts would be more easily 

 affected than other portions of the skin by corroding substances or 

 organic compounds that happen to be in the soil. Some believe the 

 bite of an insect or mechanical injury of any kind will produce 

 scabs. This may be true but some more uniform and general cause 

 is necessary to account for the disease. There is quite a general 

 belief in this Slate that chip-manure, excess of ashes, sawdust 

 manure, lime or fresh manure will cause the disease but opinions are 

 quite conflicting. It is probable that the most of these are apparent 

 instead of real causes. The station desires to study this disease 

 carefully and will be pleased to have potato growers who ma}' be 

 interested answer the following questions : kind of soil, location, 

 drainage, old or new; cro'ps the last two or three years ; method of 

 culture; fertilizers used and amount; kind of seed, scabby or not, 

 time of planting and harvesting crop, product scabby or not. What 

 conditions have you observed that seem to cause the disease. 



From what has been observed it would be advisable to drain well 



the soil upon which potatoes are to be grown and keep it loose and 



porous. Avoid an excess of fertilizers that would produce in the 



boil corroding organic compounds. Harvest the potatoes as soon as 



matured. 



INJURIOUS PLANTS. 



APPLE SCAB OR BLACK SPOT. 



{Fu is icladium dendriticu m , ) 



Attention has been called to this fungus parasite as doing consid- 

 erable damage to apples in the State. Apples marketed in Orono 

 and Bangor have been examined and the disease found to be com- 

 mon in this region. We also learn that it is prevalent in other por- 

 tions of the State. The disease is widespread over the country 

 destroying in some of the States annually fi'om one-half to one-sixth 

 of the crop. 



This fungus attacks the twigs, buds, leaves and fruit, but is most 

 noticeable on the fruit, appearing as olive green spots, with a circular 

 outline, which become velvety as they get older. When the fungus 

 attacks the twigs and leaves it affects the vitality of the tree. The 

 greatest injury is done to the fruit, the marketable product. An 

 early attack causes the fruit to shrivel and drop — a later attack pro- 

 duces a withered stunted growth, while a late attack upon the full 

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