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University of Illinois Extension

Pine Diseases Chart

by Jim Schuster retired University of Illinois State Extension Educator – Horticulture & Plant Pathology

 

Needle Blight
(Dothistroma sp.)

Brown Spot
(Sricca sp.)

Needle Cast
(Lophodermium sp.)

Tip Blight
(Sphaeropsis sp.)

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


Filed under plants: Evergreen Trees & Shrubs

More information is available on Hort Answers.