| Plant |
Disease |
Remarks |
| Ash |
Anthracnose |
Green ash is relatively resistant. |
| Ash yellows |
Both white and green ash are affected, but green ash often tolerates infection without progressive decline. |
| Azalea and Rhododendron |
Phytophthora root rot |
The most resistant cultivars of azalea include Formosa, Fakir and Corrine Murrah. As a group, Indica hybrids are most resistant. Resistant cultivars of rhododendron include Caroline, Professor Hugo deVries and Red Head. Note: extremes in soil moisture often affect susceptibility. |
| Cotoneaster |
Fireblight |
Cotoneaster adpressus, C. apiculatua, C. dielsiana, C. foveolatus, C. franchetii, C. integerrimus, C. apiculatua, C. nitens and C. zabelii are reported to be resistant. |
| Cottonwood |
Mycosphaerella (Septoria) leaf spot and stem canker |
All native North American species of poplar and aspen are susceptible. Check with local nurseryman or catalogs for information about resistant clones. |
| Crabapple |
Cedar-apple rust, Fireblight and Scab |
The following crabapples types are reported to be resistant to all three common diseases: Adams, Adirondack, Autumn Glory, Beauty, Centurion, Color Parade, David, Dolgo, Donald Wyman, Doubloons, Gibbs Golden Gage, Golden Raindrops, Indian Summer, Jewelberry, Molten Lava, Narragansett, Pink Princess, Prairiefire, Prof. Sprenger, Robinson, Sargentii, Strawberry Parfait, Sugar Tyme, White Angel and White Cascade. Check with nurserymen or catalogs for other varieties. Resistance may vary under different growing conditions. |
| Elm |
Black leaf spot |
Chinese, Japanese and Siberian elms are somewhat resistant. Resistant clones include Dynasty, Groeneveld, Homestead, Jacan, Pioneer, Regal, Sapporo Autumn Gold, Thompson and Urban. |
| Juniper |
Phomopsis tip blight, Cedar-apple and related rusts |
The following have resistance to both Phomopsis tip blight and the rusts: Juniperus chinensis cv. Foemina and var. sargentii, J. communis cv. Aureospica, cv. Suecica and var. saxatilis, J. sabina, J. squamata var. fargesii and J. virginiana cv. Tripartita. |
| Lilac |
Powdery mildew |
The common lilac, Syringa vulgaris, is more severely affected than other Syringa spp. |
| Callery Pear (Flowering Ornamental Pear) |
Fire blight |
The following cultivars are reported as highly susceptible, 'Aristocrat','Autumn Blaze','Capital', 'Fauriei'and 'Redspire'. The following are moderately susceptible, 'Cleveland Select', 'Earlyred' and
'Whitehouse'. 'Bradford' is moderately resistant. |
| Pine |
Brown spot |
In Scots pine, short needle varieties from France and Spain are very susceptible while long needle varieties from Germany and Austria are resistant. |
| Dothistroma needle blight |
Scots pine generally are resistant. |
| Pine wilt |
Under Missouri conditions, shortleaf, jack and eastern white pines are resistant. |
| Plum |
Black knot |
resistant cultivars include: President |
| slightly susceptible: Formosa, Shiro, Santa Rosa |
| moderately susceptible: Fellenburg, Methley, Milton, Bradshaw and Early Italian |
| highly susceptible: Stanley, Damson, Bluefree and Shropshire |
| Plum pockets |
Commercial varieties from European and Asian sources are not susceptible. |
| Pyracantha (firethorn) |
Fireblight |
Resistant firethorns include Pyracantha coccinea cv. `Sensation', P. koidzumii and cv. `Santa Cruz Prostrata' and hybrids, `San Jose' and `Shawnee'. |
| Scab |
The following appear to be somewhat resistant: P. coccinea `Government Red', `Prostrata' and `Rutgers', P. koidzumii `Bella', `Duval', `Santa Cruz Prostrata', `Flava' and hybrid `Shawnee', `Firey Cascade'. |
| Rose |
Black spot |
Yellow or gold flowering types generally are more susceptible than red or pink ones. Rosa rugosa cultivars and hybrids, and R. wichuriana cultivars generally are resistant. Because of the wide variety of cultivars and hybrids available, consult catalogs or your local nurseryman for more information. |
| Powdery mildew |
Species and cultivars differ widely in susceptibility. |
| Spruce |
Rhizosphaera needlecast |
Norway spruce are relatively resistant. |
| Sycamore |
Anthracnose |
Native sycamores are highly susceptible. London plane trees are resistant, but hybridization with susceptible sycamores can produce susceptible seedlings. Resistant clonal lines include `Bloodgood', `Columbia' and `Liberty'. |
