See UW-Extension Bulletin A2620, or contact your county Extension agent. Early identification and removal of infected areas is the best method of control. If you have established trees that are suffering from Dothistroma needle blight, remove fallen needles from around the base of these trees as these can serve as a source of fungal spores.įor more information on Dothistroma needle blight: Be sure to provide adequate spacing between trees to ensure good airflow and promote rapid needle drying. The tips of infected needles turn brown as the bases stay green. The spots can enlarge into reddish-brown bands and encircle the needles. When planting new trees, make sure they are disease-free. Mycosphaerella pini) (fungus) DAMAGE/SYMPTOMS Reddish-brown spots appear randomly on needles in late summer to fall. Bareroot seedlings and natural regeneration can be particularly at risk from this disease, more so than containerized seedlings, because they can stay in the. Use white or Black Hills spruce, or white fir instead. Brown spot needle blight (Mycosphaeralla dearnessii, formerly Scirrhia acicola) can heavily infest longleaf pine seedlings in the grass stage and repeated defoliations can cause death. How do I avoid problems with Dothistroma needle blight in the future?ĭo not plant Austrian pines as they are extremely susceptible to Dothistroma needle blight. Seedlings ( 40% of the crown affected) may not survive and should be removed. Young trees are more likely to suffer damage than older trees. The tip of the needle beyond the band eventually dies leaving the base of the needle alive and green.
The spots become tan, yellow, or reddish-brown, and may encircle the needles to form bands. What does Dothistroma needle blight look like?ĭothistroma needle blight first appears as dark green, water-soaked spots on the needles.
Apply treatments at 3-4 week intervals, beginning when new. In Wisconsin, Austrian pines are most commonly and severely affected by this disease. Preventive fungicide applications to the newly developing foliage will suppress new infections. Jim Olis* and Brian Hudelson, UW-Madison Plant Pathology *Completed as partial fulfillment of the requirements for a BS in Plant Pathology at the University of Wisconsin Madison.ĭothistroma needle blight is a common needle disease that can affect over thirty species of pine trees. Browning of needles typical of Dothistroma needle blight.
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