by Jim Schuster retired University of Illinois State Extension Educator – Horticulture & Plant Pathology
Needle Blight |
Brown Spot |
Needle Cast |
Tip Blight |
|
Time of infection |
New needles – midsummer to Oct Older needles- may to Oct (worse in Sept & Oct) |
Early in growing season |
Usually August and September |
As new growth emerges |
Time from infection to symptoms |
5 weeks to 6 months |
Several weeks |
Several weeks |
Several weeks |
Symptoms |
Water soaked lesions that become tan to light brown spots – needles may break off or fold at the infection site |
Gray-green to gray-black that turn brown with yellow halos. Eventually needles turn all brown. New shoots & needles often die by fall. Needles may or may not fall off |
Brown spots with yellow halos. Eventually needles turn all brown in April & May and fall off leaving only new growth in June & July |
Bleeding at base of branch tip & browning of foliage |
Time to look for symptoms |
Throughout the year |
Summer to fall |
Late summer thru late spring |
Late spring to winter |
Some susceptible hosts |
Austrian & Ponderosa most, Lodgepole, mugo, Japanese red, slash & western white often |
Ponderosa & red most, Jack, Scots & black sometimes |
Austrian, red & Scots most. Jack & white almost never |
Austrian, ponderosa, Scots most, mugo, red, swiss stone pinion & eastern white sometimes |