174 REPORT OF THE BOTANIST OF THB 
CANKER (Spheropsis malorum Pk.)—Canker® on the limbs and 
trunks of apple trees is common throughout the whole disirict. 
From the nature of the disease it is difficult to determine 
whether it has increased or decreased in virulence during 1900. 
The fungus causing canker is also the cause of the black rot of 
the fruit, and what appears to be the same fungns sometimes 
attacks the leaves. We have searched carefully for it on both 
fruit and leaves in many orchards where canker was abundant. 
Occasionally we have found it attacking fruit still hanging on 
the tree but the damage it does there is insignificant; its worst 
effects are seen among stored fruit. We have failed to find the 
fungus on apple leaves anywhere in Western New York.” 
We have also sought for Cordley’s" apple-tree anthracnose 
fungus, Gleosporium malicorticis, but failed to find it. 
MACROPHOMA CANKbR.—On May 10, we observed that the bark 
on some cankered apple limbs in the Station orchard was thickly 
covered with conspicuous creamy-white specks of pinhead size. 
Upon microscopic examination these white specks proved to 
‘be masses of the exuded spores of Macrophoma malorum (Berk.) 
- Berl. & Vogl. May 12 the same thing was observed in abundance 
at Waterloo; May 16 at Dresden and Phelps; May 23 at Barker; 
and May 24 at Hilton. It is plain that the exudation of 
Macrophoma spores on apple limbs during May was a common 
occurrence. As a rule, the exudation was noticeably more 
abundant on the side of the limb not exposed to the sun. At 
Geneva the weather conditions preceding the exudation of spores 
were as follows: For about a week prior to May 7 the weather 
was cold and dry. During the night of May 7 there was a heavy 
rain. May 8 was very warm and with a light rain at night. 
May 9 was cloudy, damp and cold, becoming clear and colder at 
night. 

*lor a full discussion of apple-tree canker see Buls. 163 and 185 of this 
Station. : 
We have, however, collected it on apple leaves at Bayside, Long Island, 
during the past season. 
“Cordley, A. B. Some Preliminary Notes on Apple-Tree Anthracnose. 
Oreg. Agr. Exp. Sta., Bul. 60. 
