Threatening Plant Diseases not Reported, or of Limited Distribution, in the U.S.

Type*	Disease***	Pathogen	Major Host	1995- Distribution[Needs an update]	Threat**
Fo	Larch canker	Lachnellula willcommii	Larch	Europe	3
Fo	Brown rust of larch	Triphragmiopsis laricinum	Larch	China	3
Fo	"oak disease"	Phytophthora quercina sp nov.	Oak	Europe	3
Fo	Needle blight	Cercospora pini-densiflorae	Pine	Japan	2+
Fo	Resin top disease	Cronartium flaccidum	2-needled Pines	Europe	3
Fo	Pine twist rust	Melampsora pinitorqua	2-needled Pines	Europe	3
Fo	(blue stain of beech)	Ceratocystis nothofagi	Nothofagus	S. America	3
Fo	(armillaria root disease)	Armillaria novae-zelandiae	Hardwoods and pine	Australia, New Zealand, PNG	2
Fo	(blue stain of beech)	Ophiostoma valdivianum	Nothofagus	S. America	2
Fo	Phytophthora disease of alders	Phytophthora alni	Alder	Europe	3
Fo	(root disease and wilt)	Leptographium truncatum	All pines	New Zealand, S. America, Canada	3
Fo	Watermark disease	Erwinia salicis	willow	Europe, Japan	3
Fo	Pink disease	Erythricium salmonicolor	fruit trees, woody perennials	Humid tropics, FL, LA, MS	3
Fo	Sudden Oak Death	Phytophthora ramorum	Oaks, Ericaceae	Germany, CA, OR	3
Fo	Scleroderris canker (European)	Gremmeniella abietina(European strain)	pine, other conifers	Europe, Canada	2+

* FF: field and forage; Ve: vegetable; Fr: fruit; OT: ornamentals and turf; Fo: forest ** Threat to U.S. *** These are not necessarily accepted common names… A disease can be a threat because of its impact on yield (quantity or quality) and international trade, toxin production, very high cost of control, etc.

0: No real threat to U.S. (remove from list); 1: Small threat (could have some economic impact if uncontrolled); 2: Moderate to large threat; 3: Severe threat (must be kept out, or immediately eradicated if discovered, at all costs). Numbers for threat represent a preliminary average score. Very tentative.

The forest pathogens were provided as a consensus from the Forest Pathology Committee. The list of forest pathogens was reviewed and modified by Joe O'Brien and Linda Haugen on 9/17/01.