TWENTIETH ANNUAL MEETING. 65 



thousaiuls in a single leaf. Within these hollow pimples 

 the winter spores are formed in great numbers. Just as 

 the blossoms begin to show color and the young leaves are 

 unfolding these spores ripen. Then if a rainy, cloudy period 

 of a day or so conies on, these spores are shot into the air 

 by millions. I\Ir. Wallace caught the spores from a square 

 inch surface of an old apple leaf and estimated that in 

 forty-five minutes twent^'-five thousand had been dis- 

 charged. This will give you some idea of how numerous 

 the apple scab spores must be on a cloudy rainy day when 

 apple buds are opening. These spores being very light. 

 are carried by the slightest breeze to the leaves and the 

 pedicles of the blossoms. Here they lodge, germinate, and 

 in about a week scab spots appear. These facts will help 

 vou to see how it is that tlic application just before the 

 blossoms open (when color shows in the bud), protects 

 the foliage and often insures a set of point. For if the 

 leaves are covered with lime-sulphur or Bordeaux the 

 spores when they fall on the leaves will not be able to 

 grow, being killed by the fungicide. The falling of the 

 young fruits a short time after blossoming is frecjuently 

 due to scab spots on the .pedicles, that were started by the 

 spores from the old leaves on the ground, scattered at this 

 time. Growers commonly attribute this early drop to cold 

 weather or frosts. I am satisfied that it is as frequently 

 caused by the scab fungus, at least in the State of New 

 York. 



Proper spraying before the blossoms open by eliminat- 

 ing scab infection of the leaves prevents burning of the 

 foliage by later applications. Extensive study and obser- 

 vations by Mr. Wallace during the past two seasons have 

 shown that scabby foliage, more than any other one thing, 

 has been responsible for much of the foliage injury report- 

 ed. The fungus by prying- off the protective cuticle of the 

 leaf where the scab spot appears lets the caustic spray 

 mixture right into the leaf tissues, thus causing the burn- 

 ing. Leaves protected from the scab, therefore, by the 



