As a result, infected needles may produce a lot of sap in response to the infection. One proposed mechanism of resistance involves the plant inhibiting fungal growth by producing fatty acids and resin, or sap, on the surface of needles. There are no species of pine that are completely resistant and resistance will vary greatly among the same species. General instructions for sample collection and shipment can be found at: and directing your browser to the diagnostic laboratory sample submission information. Care should be taken not to expose the bag to excessive heat or cold so that the specimen and pathogen remain alive until the sample is received. Plant tissues should be sealed in a plastic bag and sent to: Utah Plant Diagnostic Lab, Department of Biology, 5305 Old Main Hill, Logan, UT 84322. To do this, collect several branches exhibiting symptoms of infection. If confirmation is desired, the sample may be sent to the diagnostic lab. Local county Extension agents may be able to do this for you. To be sure that Dothistroma needle blight is the problem in your tree, they can be sampled and checked for the the fungus. They then disperse and start infectioning other trees. The spores are exposed as the stromata push through the outer layer of the needle, rupturing it. Stromata will mature and begin producing spores in the spring. It is typically shorter in the spring and longer in the winter. The interval from infection to when symptoms appear can vary from 4 weeks to 6 months, depending on environmental conditions and hosts. After the first year the disease has occurred, lesions in all stages of development and sporulation can be found throughout the growing season. Second-year needles and older needles can become infected from May to October.

First-year needles are typically infected beginning of mid-summer. Small black fungal structures called stromata will break through the outside of the dead parts of the needle, either singly or in groupsĭothistroma needle blight most often has only one disease cycle each year, although secondary cycles can occur in areas with a mild, moist climate.

Small yellow, tan, brown, or red lesions.Symptoms of Dothistroma blight are very similar to another pine disease, brown spot needle blight, which is also caused by a Mycosphaerella fungal species. Symptoms of this disease can be very similar to another pine disease, brown spot needle blight. This banding symptom is due to the accumulation of toxins produced by the fungus. It is also know as 'red band' disease in the western United States. Needles may produce resin, or sap, as a defense mechanism to inhibit fungal growth.ĭothistroma needle blight is a fungal disease that occurs on a variety of coniferous trees. Stromata under the epidermis of the needle that will emerge soon, dispersing spores for new infections. Needles will die back to the lesion and break off, leaving a gray or ashy appearance on the needle tips. The red banding symptoms observed on infected needles is the most distinctive symptom of this disease.