Armillaria root rot

Armillaria root rot
Armillaria fuscipes
Armillaria heimii Pegler
Root rot

White thick mycelial mat under the bark of stems, white mycelial mat on roots, fruiting bodies at the stem base, die back at advanced stage of disease, basal cankers with resin oozing from the stem.

Production of thick white mycelial mats, production of rhizomorphs (shoe string like structures) in culture and sometimes on the roots. During the sexual phase mushrooms are formed with caps up to 51 mm (average 35 mm) diam, convex later broadly plane, center broadly umbonate sometimes depressed encircling zone, citrine in the center, becomes orange yellow to shades of light cream at margin, brussels brown squamules are present on the cap, margin of cap incurved, striate. Lamellae: white, decurrent, close. Stipe: 64-87 mm X 2-4.5 mm, central, cylindrical, solid, olive gray becomes lighter towards the ring, buff coloured just above the ring, becomes citrine towards the apex, pale olive gray flocci are present from base to ring, brownish white inner tissue. Ring: close to apex, membranous saccate, circumscissile, whitish.    

1900’s (as Armillaria mellea) (Pole Evans 1933, Kotzé 1935, Bottomley 1937)
KwaZulu-Natal,Limpopo,Mpumalanga
Africa (Coetzee et al. 2005 and reference therein)

Image

Armillaria fuscipes mushrooms