Charles H. Bronson, Commissioner    -    James R. Karels, Director
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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 CAST

Needle cast.
Red-brown discoloration of pine needles typical of needle cast fungus infections.
Pathogens: Various fungi
Ploioderma spp.
Lophodermium spp.
Common Host: Pines Pinus spp.
Significance:
 Needle cast affects all of Florida's major pine species. In some years this disease develops to spectacular levels resulting in large numbers of trees giving the appearance of having been scorched by fire. Some degree of growth reduction due to premature loss (cast) of foliage is presumably the primary impact of this disease on infected trees. However, severe needle cast, in combination with other stresses such as drought or injury could well contribute to the vulnerability of trees to stress-related pests such as bark beetles. In most cases, the effects of needle cast on otherwise healthy trees are negligible. See Figure 10: Life cycle of a typical needle cast fungus.
Recognition:
 Infected needles generally turn red to brown from their tips beginning in winter or early spring. By mid to late spring the death of infected needles is well advanced giving diseased trees a red to brown "fire-scorched" appearance. Some individual trees are highly susceptible to needle cast fungi while others possess a high degree of genetic resistance. Therefore, it is not uncommon to see severely infected and perfectly healthy trees side by side. Following actual needle cast, the remaining green needles often appear somewhat tufted at the ends of branches. Small (1-2 mm), black elongate fruiting bodies (hysterothecia; sing., hysterothecium) of needle cast fungi are sometimes visible upon close inspection of symptomatic or dead needles.

Infection Biology:

 Microscopic spores, called ascospores, are produced in the fruiting bodies (hysterothecia; sing., hysterothecium) of the needle cast fungi on symptomatic or dead needles. Ascospores are liberated into the air where they are then disseminated largely by wind and rain. New infections occur when the ascospores are deposited on young, emerging needles of susceptible pines during the spring and early summer.
Control:
 Control is unnecessary in most situations. If control is desired for cosmetic reasons, protection of newly emerging needles through June with regular applications of an appropriate fungicide may be helpful.

 




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


Florida Department of Agriculture and Consumer Services