Black Stain Root Disease
From Bugwoodwiki
Contents |
Hosts
Douglas-fir, lodgepole pine, ponderosa pine, and eastern white pine are known to be infected in Idaho and Montana.
Distribution
This disease has been found in relatively few locations in Idaho and Montana. All known locations in Montana are west of the Continental Divide.
Damage
Trees are killed by the fungus growing in trachieds and blocking water conduction. Bark beetles usually attack infected trees.
Identification
Trees with black stain root disease may have crown symptoms typical of root diseases but often they die too quickly for root disease crown symptoms to develop. In this case crowns remain full and needle length near normal, while the entire crown fades uniformly to yellow and then red. The disease is indicated by brown, or black stain in roots and root collar sapwood (fig. 69) which follows the annual rings. In cross section the stain forms concentric crescents in the sapwood (fig. 70). Presence of black stain root disease is sometimes obscured by Armillaria root rot which often attacks trees with black stain root disease.
Similar damages
Blue stains caused by nonpathogenic or only weakly pathogenic fungi are common in dying or dead trees. Contrary to their name 'blue' stains can be black, brown, or even red. Blue stains do not follow the annual rings. They are wedge-shaped and follow the rays inward from the cambium.
Table Comparison of Common Root Diseases
| Fungus | Hosts | Basal Resinosus | Decay | Other Distinguishing Characteristics |
|---|---|---|---|---|
| Armillaria ostoyae | 1. DG, GF, saping pines 2. Other conifers | Yes | White or yellowish, stringy with black zone line and rhizomorphs | Thick fan-shaped felts of white mycelium in cambium |
| Phellinus
wirii | 1. DF, GF
2. Other conifers | Yes | Laminated, separating at annual rings, pitted with pinhead-sized holes | Cream-colored mycelium on outer bark of roots and root collar under duff. Cinnamon-colored mycelium often in bark cracks with cream cycelium. |
| Phaeolus schweinitzii | 1. DF
2. Other conifers | No | Brown cubical rot of root and butt heartwood | Small roots with red-brown resinous heart; galled roots; large brown, velvety conks with green or brown pore layer on underside produced on ground or base of tree. |
| Fomes
annosus | 1. DF, GF
2. SAF, WH, PP, WRC, WWP | No | White or yellowish, stringy to somewhat laminate. White pockets with black flects sometimes present | Conks shelving or flat on sides in hollow stumps. Conks have brown upper surface and white lower, pored surface with brown, non-pored margin. Cream-colored mounds (button conks) below duff on seedlings. |
| Ceratocystis wageneri | 1. PP,LPP, DF
2. ? | No | No decay produced | Black or brown stain in sapwood follows annual rings. |
References
Anonymous. 1982. For. Insect & disease identification and management. USDA For. Serv.,Northern Region; Idaho Dept. of Lands, Insect and Disease Control; Montana Dept. of State Lands, Division of Forestry. 192 p.
Bega, R. V. 1978. Diseases of Pacific Coast conifers. USDA For. Serv. Ag. Hndbk. No. 521, 206 p.
Smith, R. S., Jr., and D. Graham. 1975. Black stain root disease of conifers. USDA For. Serv., For. Pest Leaflet 145, 4 p.
Field Guide to Diseases and Insect Pests of Idaho and Montana Forests, USDA Forest Service Northern Region, Publication Number R1-89-54
