Charles H. Bronson, Commissioner    -    James R. Karels, Director
  Download Document Viewers



Conifer Foliage Diseases:
Needle Rust
Needle Cast
Brown Spot Needle Blight
Southern Cone Rust
Foliage Blights of Junipers and Related Conifers
Cedar Apple Rusts


 
Forest Health > Insects and Diseases publication

Diseases of... Conifer Foliage

Common Name:

 

NEEDLE RUST

Needle rust fungus.
Papery, white aecial pustules of a needle rust fungus on pine; appear in late spring or early summer.
Pathogens: Various fungi Coleosporium spp.
Common Host: Pines Pinus spp.
Alternate Host: Various broad-leaved plants
Significance:
 Most species of pines in Florida can become infected with needle rust fungi. Needle rust is a common disease, often causing considerable distress to tree lovers seeing it for the first time. Fortunately, the disease is generally innocuous, having little, if any, impact on affected trees. Only where particularly severe infections occur in nurseries, young pine plantations, or high value ornamental plantings is this disease any more than a curiosity. See Figure 9: Generalized life cycle of needle rust fungi.
Recognition:
 Infections are usually first noticed in late spring or early summer when small papery white pustules begin to emerge from the surface of infected pine needles. Soon these pustules, called aecia, (sing., aecium) become filled with yellow-orange spores that are later released into the air in small puffs or clouds when the needles are jarred or shaken by wind.

Infection Biology:

 Spores produced on pines do not reinfect pines, but as is typical of most rust fungi, they initiate infections on other plants referred to as alternate hosts. Common alternate hosts for Coleosporium spp. include goldenrods, asters, sunflowers, morning-glories, and others, depending upon the particular species of rust fungus. A different spore type is produced later in the season on the infected leaves of the alternate host. Reinfection of susceptible pine needle tissues by these spores results in new pine infections.
Control:
 Control of needle rusts is seldom necessary. If control is desired, fungicidal protection of vulnerable pines during late summer and fall may be useful. Otherwise, avoid planting of pines near heavy populations of the alternate host(s) and eradicate alternate host plants growing near susceptible pines where practicable.
Needle rust fissures.
Yellow-orange fissures in pine needle infected with a needle rust fungus: appear in late spring.



Bulletin No. 196-A | Printed October, 1983 | Contact the Forest Health Section
Division of Forestry Shield


Florida Department of Agriculture and Consumer Services