![]() ![]() ![]() Needles on lower six feet of a tree are most noticeably affected. These black, pimple-like structures produce fungal spores. Within the spots and bands, you may see tiny bumps pushing through the surface of the needle. Older needles found close to the trunk are more severely affected compared to the younger needles that are found towards the ends of the branches. The transition from green to dead areas is abrupt.Įventually, needles turn completely brown and fall off. These two sections are separated by a reddish-brown band. Tip of the needle turns brown while the base of the needle remains green. These spots grow into a band, encircling the needle. ![]() Reddish-brown spots scattered on green needles. ISBN: 978-1-88.Young tree infected with Dothistroma needle blight has browning of older needles as well as bare branches from needle drop Needle symptoms Insects and Diseases of Woody Plants in Colorado.Compendium of Conifer Diseases, Second Edition.Tan or brown needle tips (often with a distinct interface between dead and live tissue) that start as yellowish or reddish-brown spots, eventually forming a distinct band around needles dark fruiting bodies (acervuli) with olivaceous, elongate, curved, one- to five-septate conidia: Brown spot needle blight.Photo by Eva Grimme, Montana State University. Reddish-brown band with resin droplet on pine tree needle caused by Dothistroma sp. Tan or brown needle tips (often with a distinct interface between dead and live tissue) that start as dark-green (water-soaked), tan, or reddish-brown spots, eventually forming a band (possibly with small resin drops) (Figure 4) around needles dark fruiting bodies (stromata) with hyaline, elongate, and one- to five-septate conidia: Dothistroma needle blight.įigure 4.Tan or brown needle tips with discoloration fading into green tissue at the base of needles (on trees near roads where salt is used for winter snow management): salt spray damage.Pine (primarily Austrian, ponderosa, mugo) Fruiting bodies of Sudden needle drop on a spruce tree branch. Photo by Eva Grimme, Montana State University.įigure 3. Spherical, spiny fruiting bodies (ascocarps) form on branches or pulvini (needle pegs) (Figure 3) with pale to medium brown, septate ascospores (asci may or may not be readily visible): Sudden needle drop (SNEED).įigure 2.Clusters of conidiophores emerge from stomata (possibly easier to detect on green than brown needles) with light brown, elongate, five- to eight-septate conidia: Stigmina needle cast disease.Spherical fruiting bodies (pycnidia) emerge from stomata with small, oval, hyaline, aseptate conidia: Rhizosphaera needle cast (Figure 2).Brown, bronze, or dark-purple discoloration of inner needles: possible needle cast diseases.Reddish to brown discoloration of the needles at the tip of branches:abiotic issues such as winter injury/burn or drought stress (Figure 1).Incubation of samples for 24 to 48 hours (or longer) in a moist chamber may help with confirmation. The following are tips to help identify common pine and spruce needle problems using a 10X hand lens (or dissecting microscope) and compound microscope. Diseases and abiotic disorders can adversely affect these trees, resulting in needle discoloration and loss, as well as potential dieback. Spruce and pine trees are staples in many landscapes. Photo by Brian Hudelson, University of Wisconsin-Madison.Įva Grimme, Montana State University, and Brian Hudelson, University of Wisconsin-Madison Needle discoloration due to abiotic factors.
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