Your letter of Aug. 7 is received, together with the specimens. The stems of the Corylus are affected with one of the Pyrenomycetes. Cryptospora anomala, Pk. The fungus is described in "North American Pyrenomycetes," by Ellis and Everhart, p. 531. It attacks Corylus Americana, but appears to be worst on the European varieties, as you say. The pustules appear first on the young branches, and later on the older ones and on the trunk. The roots are not killed.
The only remedy known is to cut out and burn the diseased stems. Whether Bordeaux mixture or any other copper solution will protect the shrub from attack, is not known. So far as I know, it has not been tried. It is probable, however, that if the stems were thoroughly sprayed with the Bordeaux mixture they would be protected from attack. The mycelium of the fungus grows into the cambium and practically girdles the stems. The black pustules contain the spores.
Very truly yours,
ALBERT F. WOODS, Acting Chief.
On the receipt of this note of Prof. Woods, I looked up Ellis and Everhart's work, a voluminous one of over 800 octavo pages, published by the authors at Newfield, N. J. This filbert blight is briefly described under the scientific name of Cryptospora anomala, Pk., but Prof. Peck writes me that "the description was made from specimens discovered near Albany, N. Y., in May, 1874. In 1882 this description was republished by Saccardo, in his "Syllage Fungorum," Vol. I, p. 470, under the name of Cryptosporella anomala. The original name in Report 28, p. 72, was Diatrype anomala. In 1892 Ellis and Everhart, in "Pyrenomycetes of North America," p. 531, changed the name again, making it Cryptospora anomala." So at present we have the names of this fungus in the following order:
Diatrypes anomal, Peck, 1876.
Cryptosporella anomala, Sacc., 1882.
Cryptospora anomala, E. and E., 1892.
Ellis and Everhart, after giving scientific description, add,
"On living stems of Corylus Americana, Albany, N. Y. (Peck), Iowa (Holoway), on Corylus Avellana, Newfield, N. J. The pustules appear first on the smaller branches, and are serrately arranged along one side of the branch; afterwards they appear also on the larger branches and on the trunk itself, and in the course of two or three years the part of tree above ground is entirely killed. The roots, however, still retain their vitality, and continue to send up each year a luxuriant growth of new shoots, destined to be destroyed the succeeding year by the inexorable pest. The imported trees seem to be more injuriously affected than the native species."
The observations of Ellis and Everhart and Prof. Woods accord with my own, but I may say that the infested branches often show the presence of the mycelium in the bark and alburnum,—by a slight shrinking,— weeks or months before the pustules appear, for these are merely indications of the last stage in the life of the fungus, and with the throwing off the spores from these pustules the old parasite perishes.
The pustules, when fully open, are from one-sixteenth to one-eighth of an inch in diameter, usually round, but sometimes slightly oval in form, and placed mainly in almost straight rows lengthways of the branch, as shown in Fig. 44. These pustules appear on wood of all ages, from two years upward, and in what may be termed patches, ranging from a few inches to a foot or more in length, and more frequently on the upper side than the underside of the branches.