STATE POMOLOGICAL SOCIETY. 5 1 



Another line of inquiry which we have been following up this 

 season is with regard to the amount, distribution, and causes 

 of leaf spot of the apple. We find that this trouble is almost 

 universal in Maine, no locality or variety being free from it 

 except, possibly, in the case of some of the varieties grown 

 under conditions in Aroostook. In very many cases it has been 

 found to be ver}' severe, even causing considerable defoliation, 

 and without doubt does much to weaken the vitality of the trees. 

 By the leaf spot I mean the little dead, reddish-brown areas, 

 usually nearly circular in outline, which are found scattered 

 over the leaves. Other names such as "frog-eye," "brown- 

 spot," "leaf blight," etc., have been appHed to it. Recently it 

 has been shown that the same fungus (Sphaeropsis malorum 

 Pk.) which, as has already been stated, causes the black rot 

 of the fruit and the more common limb canker, is also respon- 

 sible for a similar if not identical leaf spot in the Ozark apple 

 region. This is a very important fact and we felt that we 

 should at once determine if the same thing is true in the Maine 

 orchards. If it is, a campaign waged against one of these 

 maladies should be directed also toward and be effective against 

 the other two. If it should happen that other fungi with us 

 may also cause leaf spot we should determine this fact and thor- 

 oughly study the fungus in question so that we may be able to 

 intelligently take up the question of its control. Leaves w^ere 

 obtained from 9 different towns, sometimes from several differ- 

 ent orchards in a town, representing the counties of Cumber- 

 land, Kennebec, Penobscot, and Piscataquis. A surprising 

 number of different fungi were secured from these spots, but 

 doubtless the majority of them are saprophytes following along 

 after the tissues are killed. The only way we can be sure of 

 which of them are responsible for the injury is to spray the 

 spores on healthy leaves and see which produces the disease. 

 Unfortunately it was so late in the season when the work was 

 started that all inoculations in the field failed to produce results. 

 However, we now have a small greenhouse at our disposal and 

 have made arrangements to fill it up with seedling apple trees 

 this winter upon which we shall test out the cultures. If we 



