Pine Needle Cast Disease: Identification and Fungicide Treatment

When pine needles turn reddish-brown in early summer, causes could be trunk beetles, root compaction, or needle disease.

Year after wet summer, 'needle cast' may cause numerous pines to become 'red-topped'.

Usually interior needles affected; new needles on branch tips remain green. Disease infected older needles during wet weather previous summer. Young needles current year not yet infected, sporulation occurs late summer.

If current summer dry, needle cast halted, pine recovers. If wet, disease may kill young pines.

Dr. Jean Williams-Woodward: "Most likely cause: fungus Lophodermella cerina, Lophodermella needle cast. Spores on infected one-year-old needles spread to current year's growth late summer.

Needle cast diseases typically controlled by chlorothalonil (Daconil, Bravo). Bayleton (triadimefon), Cleary's 3336 (thiophanate methyl), Banner Maxx (propiconazole) also labeled. Applications, if desired, begin early July to protect fully expanded current year's growth."

Red-Topped Pines in Urban Forest: Guide to Recognition and Roles of Pine Bark Beetles and Needle Cast Disease