Insect Blog

Marssonina Leaf Blight

May 14th, 2019

Plants Affected:

Aspen, cottonwoods, and poplars.


Tan or brown spots appear on the leaves which gives them a blackened appearance.

Live Cycle:

This disease is aggravated by wet humid weather. Heavy infections may follow wet or humid spring conditions.


Spraying may help reduce infections of this disease but as of yet there is no good chemical control.  Cultural practices such as raking up leaves in the fall, pruning to promote better air movement, and making sure the sprinklers are not hitting the foliage are recommended.  Even severe infestations will usually not adversely affect the tree if it is relatively healthy.