Dothistroma Needle Blight

Image of Dothistroma on an Austrian Pine
Dothistroma on an Austrian Pine 

Need to know:

  • Brown bands will appear on infected needles and the portion beyond the band will die.

Overview of Dothistroma needle blight

Dothistroma needle blight is especially common on Austrian pines.

Symptoms of Dothistroma needle blight

Early symptoms of dothistroma needle blight include resin-soaked needles with dark green bands and spots that may be dark green, yellow, or tan in color. Trees are often affected from the bottom of the canopy working up. As the disease progresses the bands and spots turn to a brown or reddish-brown color. In the fall or over winter the parts of the needle past the band may die and turn brown.

See this article about Dothistroma needle blight.

Early symptoms of dothistroma needle blight include resin-soaked needles with dark green bands and spots that may be dark green, yellow, or tan in color. Trees are often affected from the bottom of the canopy working up. As the disease progresses the bands and spots turn to a brown or reddish-brown color. In the fall or over winter the parts of the needle past the band may die and turn brown.

Type of Sample Needed for Diagnosis and Confirmation

The Iowa State University Plant & Insect Diagnostic Clinic can help you to investigate and confirm if you plant has this disease. Please see our website for current forms and fees. Contact information for each states diagnostic laboratory for U.S. residents.  If your sample is from outside of Iowa please do not submit it to the Plant & Insect Diagnostic Clinic without contacting us

To confirm Dothistroma needle blight we need to examine a sample under the microscope. Samples should include symptomatic needles, living and still attached to a branch. Branches can be packed into a box with paper towel for shipping. DO NOT add water to the samples. If you are uncertain  about the type of sample feel free to contact us.

Fungicide applications may be avoided by following good Integrated Pest Management practices like those listed in this encyclopedia article. Often, the only preventative application is effective to manage plant diseases. If the problem requires a fungicide, state law requires the user to read and follow all labels accordingly. For more information, read Proper fungicide use.

Closeup image of Dothistroma on an Austrian Pine
Dothistroma on an Austrian Pine 

 

 

 

 

 

 

 

 

 

 

 

 

Image of Dothistroma on the needles of an Austrian Pine
Dothistroma on the needles of an Austrian Pine 

 

Authors: 

Lina Rodriguez Salamanca Extension Plant Pathologist and Diagnostician

Dr. Lina Rodriguez-Salamanca is a diagnostician and extension plant pathologist with the Iowa State University Plant and Insect Diagnostic Clinic  (clinic.ipm.iastate.edu), a member of the National Plant Diagnostic Network (NPDN, ...

Last Reviewed: 
April, 2022
Category: 

Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on . The information contained within may not be the most current and accurate depending on when it is accessed.