Sick oak in Rockville? - Ask Extension
Hi, I've just noticed that one of my oak trees is looking sick. It sits in a cluster of 2 other mature oak trees, both of which appear healthy. This ...
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Sick oak in Rockville? #252975
Asked June 10, 2015, 1:25 PM EDT
Hi, I've just noticed that one of my oak trees is looking sick. It sits in a cluster of 2 other mature oak trees, both of which appear healthy. This is the first season I've noticed the problem. The leaves are prematurely browning and drying. There are tiny white hairy bugs on the underside of the leaves and lots of small holes chewed in the leaves. There is also a white fuzzy substance on the underside of leaves. In prior years another one of the oaks was affected with slime flux, if that matters.
Montgomery County Maryland
Expert Response
Your tree has several issues, but the two major ones are jumping oak gall and anthracnose.
Jumping oak gall is the gall formed from the egg laying of a tiny wasp. The larva lives inside. (Look at search engine images.) Like many galls, the population varies greatly from year to year and tree to tree. It does not need to be controlled. Here is a good (and interesting) website about it: http://extension.missouri.edu/news/DisplayStory.aspx?N=806
The anthracnose is a fungal disease and is very weather dependent. Here is info from our website: http://extension.umd.edu/hgic/shade-tree-anthracnose-trees
Again, no control is recommended. We're getting reports of quite a bit of anthracnose this year on many species of trees.
The other things going on are incidental.
ECN
Jumping oak gall is the gall formed from the egg laying of a tiny wasp. The larva lives inside. (Look at search engine images.) Like many galls, the population varies greatly from year to year and tree to tree. It does not need to be controlled. Here is a good (and interesting) website about it: http://extension.missouri.edu/news/DisplayStory.aspx?N=806
The anthracnose is a fungal disease and is very weather dependent. Here is info from our website: http://extension.umd.edu/hgic/shade-tree-anthracnose-trees
Again, no control is recommended. We're getting reports of quite a bit of anthracnose this year on many species of trees.
The other things going on are incidental.
ECN
