Foliar Diseases
FIELD GUIDE TO INSECTS AND DISEASES OF ARIZONA AND NEW MEXICO FORESTS
White Pine Needle Cast
Lophodermella arcuata (Darker) Darker

Host:  Southwestern white pine

Figure 192. Figure 192. Lophodermella arcuata causes browning of 1-year needles, which is most noticeable just before bud break of current year needles.

Symptoms/signs:  This fungus is identified by the dark brown to concolorous, elongate to elliptical, fruiting structures, which develop on previous year’s dead and dying needles.

Biology:  Fruiting bodies in dead, second year needles open by means of a longitudinal fissure during warm wet weather and release colorless spores that have sticky, gelatinous sheaths. Airborne spores settle and penetrate young, developing needles. The following spring, diseased needles turn reddish brown and by July, they are straw colored.

Figure 193. Figure 193. Fruiting bodies of Lophodermella arcuata are the same color as the faded needle.

Effects:  Lophodermella arcuata infects only the current year’s needles, and a single attack results in only partial defoliation of the host. Repeated consecutive infections are rare, but can lead to reduced tree growth and vigor.

Similar Insects and Diseases:  This is the only known needle cast disease of white pine in the Southwest.

References:  83, 93