Foliar Diseases
FIELD GUIDE TO INSECTS AND DISEASES OF ARIZONA AND NEW MEXICO FORESTS
Red Band Needle Blight
Dothistroma septosporum (Dorog.) M. Morelet

Hosts:  Ponderosa pine and piñon

Figure 188. Figure 188. Dothistroma blight of Austrian pine.

Symptoms/Signs:  Symptoms first appear as yellow or tan bands around the needles, which later turn red. Infection of current and second year needles is usually in the lower crown of sapling size trees. Seedlings and large trees are rarely infected. Newly infected needles have green bands that turn red or brown in late summer. These needles die from the tips back. Infected second and older year needles can be cast the same year they become infected.

Biology:  Needles are infected during rainy periods by rain-splashed spores. The number of infection cycles depends on the climate. During wet years, several cycles of infection can occur. The Dothistroma septosporum stage is the asexual, imperfect stage, and the one most commonly found.

Effects:  Dothistroma needle cast has been observed on ponderosa, piñon, and Austrian pine in New Mexico. It is most often associated with offsite planting. Several years of severe infection results in reduced growth and death of infected trees.

Similar Insects and Diseases:  Infected trees can look like the lower crown was sprayed with herbicides. The death of needles from the tips to fascicle is similar to the affects caused by high concentrations of de-icing salts.

References:  78, 83, 93