CYCLANEUSMA NEEDLECAST ( Cyclaneusma minus )
Cyclaneusma needlecast was once mistaken for natural senescence occurring in the interior of pine trees. Eventually it was discovered that a fungus was indeed responsible and that it could be controlled with a fungicide. Cyclaneusma needlecast is caused by the fungus that mainly attacks Scots pine, although Austrian and Eastern white pine as well a few other pine species may also be affected. This disease may be found on all but the current season's needles.
Fig. 1. Yellow internal needles on Scots pine
Symptoms begin in early Autumn when the interior needles begin to turn bright yellow. Later the needles become more of a tan color, with darker brown transverse bands developing on the needle surfaces. The infected needles will overwinter in this manner, many of them remaining on the tree. In the spring, small ( 2-3 mm or about 1/16 in long) cream colored blisters develop on the infected needles. During wet weather, possibly beginning as early as March and going through October, these fruiting bodies split open and release spores into the air which land on needles and infect them. Needles are infected throughout the growing season as the fruiting bodies release more spores.
It is difficult to control Cyclaneusma needlecast because spore production and infection can take place whenever temperatures are above freezing and needles are wet. A registered fungicide must be used throughout the growing season and five treatments are recommended.
Fig. 2. Needles of Scots pine infected with Cyclaneusma needlecast turn yellow to tan and develop darker, transverse bands that are characteristic of this disease.
Fig. 3. Close-up of fruiting bodies (apothecia) on an infected needle.
Return to Pest Menu