ROOT ROT 

Causal fungus: Cylindrocarpon sp.

Subdivision: Deuteromycotina

Hosts: Conifer seedlings in nurseries 

Symptoms: Root rot; damping-off 

Signs: Conidiophores with conidiospores. 

Chlamydospores (rounding and thickening of mycelia during unfavorable conditions). This is common in soilborne, root pathogenic fungi. 

TO DO:

1. Make a slide from the plate and look for chlamydospores. 

2. Note the intercalary (in the middle of the hyphae) and the terminal (at the end of the hypha) chlamydospores. 

3. What is the other name for the subdivision of this fungus? 

ROOT ROT 

Common name: Armillaria root rot or Shoestring root rot

Causal fungus: Armillaria sp.

Subdivision: Basidiomycotina

Hosts: All trees and shrubs 

Symptoms:Chlorosis/necrosis of foliage; branch dieback. 

Signs: Gilled "honey mushrooms" at tree base in fall. 

Black shoestring-like rhizomorphs on roots.

White mycelial fans beneath bark.

In eastern hardwood forests, Armillaria is usually a secondary pathogen of trees stressed by other factors, but in the West, the fungus can be an aggressive pathogen of conifers. 

TO DO:

1. Observe rhizomorphs on samples and possibly in the culture plates. 

2. Note the white mycelial fans beneath the bark. 

3. Become familiar with the basidiocarp of the fungus--the "honey mushroom". 

a. What type of spores are produced? 

b. How are the spores formed on the mushroom gills? Review your notes from the second lab and draw a diagram. 

4. What are the 3 means of spread for this fungus? 

ROOT AND BUTT ROT 

Common name: Stand opening disease of conifers

Causal fungus: Inonotus tomentosus

Hosts: Most conifers, especially spruce 

Symptoms: Dieback and mortality of trees in patches. Reddish stain in infected wood.

Signs: Yellowish to rusty brown basidiocarps produced at base of tree in summer. Spore producing surface is made up of pores. 

TO DO:

1. Observe the basidiocarps. How do they differ from those of Armillaria or Phaeolus? 

2. To which subdivision does this fungus belong? 

3. What type of spores do the fruiting bodies produce? 

ROOT AND BUTT ROT 

Common name: Brown root and butt rot of conifers

Causal fungus: Phaeolus schweinitzii

Hosts: Most conifers 

Symptoms: In late stages of decay, wood turns dark brown and cracks into cube-shaped pieces called brown cubicle rot. 

Signs: Dark, rusty brown, velvety basidiocarps grow on the ground or on the base of the tree in summer and fall. 

This fungus is the most serious butt rot fungus in old-growth forests in the U.S.

TO DO:

1. Be able to distinguish Phaeolus fruiting bodies from those of Inonotus. 

2. To what subdivision does this fungus belong? 

ROOT, BUTT AND TRUNK ROT 

Common name: Artist's conk

Causal fungus: Ganoderma applanatum

Subdivision: Basidiomycotina

Hosts: Most hardwoods and some conifers 

Signs: Perennial fan-shaped basidiocarp with a brown upper surface and a white pore surface. These conks can become very large. 

TO DO:

1. Become familiar with the fruiting body. Count the layers where the conk was attached to the host and determine how old it was when collected. 

2. Look at the prepared slide of a spore-producing surface. Draw a diagram of pores, basidia and spores. What type of spores are they? 

3. Why is the common name for this fungus "Artist's conk"? 

TRUNK ROT 

Common name: Red ring rot or White pocket rot

Causal fungus: Phellinus pini

Subdivision: Basidiomycotina

Hosts: Most conifers 

Symptoms: Wood is pinkish-red in early stages of decay. 

Signs:Basidiocarps are nearly flat to large hoof- or fan-shaped conks. The upper surface is brown to black and the lower pore surface is yellowish to reddish brown. 

The fungus generally infects through wounds or branch stubs and may extend into the butt and roots. This rot is commonly associated with stem rust cankers in pine. 

TO DO:

1. Become familiar with the fruiting body. What type of spores does it produce? 

2. Note the white pocket rot and red heart rot in the wood samples. 

TRUNK ROT 

Common name: Red belt fungus

Causal fungus: Fomitopsis pinicola

Subdivision: Basidiomycotina

Hosts: Most conifers and hardwoods 

Symptoms: Brown cubicle rot 

Signs: Perennial basidiocarps that are fan-shaped to hoof-shaped with a red-brown band near the white edge of the upper surface. 

TO DO:

1. Be able to recognize the conk and distinguish it from Ganoderma sp. and others. 

2. What type of spores does it produce? 

TRUNK ROT 

Causal fungus: Phellinus igniarius

Hosts: Most hardwoods 

Causal fungus: Phellinus tremulae

Hosts: Aspens 

Symptoms: White spongy rot of wood 

Signs: Hoof-shaped perennial basidiocarps

P. tremulae is the most important decay pathogen of aspen. The spores of the fungus enter the tree at branch stubs where the basidiocarps are later produced. 

TO DO:

1. Become familiar with the conk. Note the slanted spore-producing surface and compare it to Fomes fomentarius. 

2. Note the spongy rot in the aspen cookie and the young conk growing from a branch scar. 

3. To what subdivision do these fungi belong? 

TRUNK ROT 

Causal fungus: Fomes fomentarius

Subdivision: Basidiomycotina

Hosts: Most hardwoods 

Symptoms: White mottled trunk rot 

Signs: Perennial hoof-shaped basidiocarps

TO DO: 

1. Compare the conks to those of Phellinus igniarius and P. tremulae. 

2. What type of spores does this fungus produce? 

ROOT AND BUTT ROT 

Causal fungus: Ganoderma tsugae

Subdivision: Basidiomycotina

Hosts: Conifers in the Southwest and Northeast, especially eastern hemlock 

Symptoms: White spongy rot 

Signs: Red, varnished-like basidiocarps

This fungus is not considered pathogenic and causes rot of roots and butts of dead trees. 

TO DO:

Be able to recognize the basidiocarps. 

TRUNK ROT 

Common name: Canker rot of birch

Causal fungus: Inonotus obliquus

Subdivision: Basidiomycotina

Hosts: Birch (Betula sp.) 

Symptoms: Spongy white rot of wood; canker on trunk. 

Signs: Rough black perennial sterile conk that erupts at old wounds or branch stubs. Flat brown inconspicuous basidiocarps form 3-4 years after tree dies. 

This fungus is different from the other decay fungi because mycelia of the fungus invade and kill adjacent bark and cambium resulting in a canker. 

TO DO:

1. Be able to recognize the sterile conk. 

2. What type of spores do the basidiocarps produce? 

TRUNK ROT 

Causal fungus: Oxyporus populinus

Subdivision: Basidiomycotina

Hosts: Most hardwoods 

Symptoms: Spongy white rot of wood 

Signs: Perennial spongy white basidiocarps singly or in clusters in cracks, wounds, or Eutypella and Nectria cankers. 

Green moss often grows on the upper surface of the basidiocarps. 

TO DO:

Become familiar with the basidiocarps. 

TRUNK ROT 

Common name: Turkeytail fungus

Causal fungus: Trametes versicolor

Subdivision: Basidiomycotina

Hosts: Most hardwoods and some conifers 

Symptoms: White spongy rot 

Signs: Velvety, brightly colored fan-shaped basidiocarps in clusters. Pore surface is white to cream-colored. 

Although this fungus colonizes living wood it is most often found fruiting on dead, fallen logs. 

TO DO:

Be able to recognize the basidiocarps and distinguish them from other very similar fungi that are out there. Note the pore surface. 

TRUNK & LIMB ROT 

Causal fungus: Schizophyllum commune

Subdivision: Basidiomycotina

Hosts: Most hardwoods and conifers 

Signs: Fuzzy white gilled annual basidiocarps in clusters. 

TO DO: