Stem Canker of Black Walnut Caused by Fusarium solani in Kansas. N. Tisserat, Department of Plant Pathology, Kansas State University, Manhattan 66506. Plant Dis. 71:557. Accepted for publication 11 March 1987. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0557D.
In April 1985, multiple trunk and branch cankers were noted on 64 of
184 trees in a 7-yr-old black walnut (Juglans nigra L.) plantation near
Hutchinson, Kansas. The annual stem cankers often were more than I
m long and occasionally extended to the soil line. Necrotic bark on the
canker faces commonly sloughed off, exposing discolored sapwood.
Fusarium solani (Mart.) Appel & Wollenw. emend. Synd. & Hans.
(identified by T. A. Toussoun, Pennsylvania State University) was
consistently isolated from the sapwood and cambium near the canker
margins. Four-month-old black walnut trees were inoculated by
inserting potato-dextrose agar containing mycelium and spores of F.
solani into wounds. made in the bark. Inoculated trees developed
sunken, black elongate cankers within I mo; F. solani was reisolated
from the canker margins. Symptoms of the disease are similar to those
on black walnut caused by F. sporotrichioides Sherb., F. lateritium
Nees, and F. oxysporum Schl. (1,2). This is the first report of a canker
disease of black walnut incited by F. solani.