Brown Spots on Ash Tree

We have a couple of Marshal Ashes. The one in the front yard is getting brown rusty colored spots on the leaves. It doesn't look like insects have been eating on it. No holes. Just brown spots. We live in Northwest Arkansas. The temperature has been in the upper 80's. I might have been watering it too much. I was told recently that it needs done only once or twice a week. I'm doing it about every night. Could that be the cause of the spots?
Thanks, Greg
p.s. anyone have a suggestion to get rid of johnson grass? I'm to the point where I am going to have to pull each one up by hand.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

"Rust", a fungal condition. They make a fungicide to control it. Visit your local plant nursery & see if they have a book with pictures to help you identify it.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Yes. They are orange/rust looking. I had read on a site today about this condition. I'll tear off a leaf tomorrow and take it to a nursery and see if they can confirm it.
Thanks.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Just a note on watering. Green Ash trees (Marshall is a Green Ash) don't usually suffer from overwatering. If you are watering the leaves, make sure you do it in the morning, rather than the evening to discourage fungus and mildew.

Torch them! You can also use a damp rag soaked in round-up and wipe the leaves. This method will keep you from killing the surrounding grass.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Never heard of it.
wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

MSMA is primarily used on Bermuda grass lawns. When used correctly, it's very effective against crabgrass. Johnson grass usually does not grow in the middle of a lawn because it can't survive very well when regularly mowed. You may have crabgrass rather than Johnson grass. If this is the case, and you have a Bermuda lawn, MSMA works very well especially this time of year. MSMA is also pretty cheap, but use it for spot treatment only.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Yes. I do have bermuda lawn. But I'm pretty sure this is either johnson grass or dallisgrass (from the pictures I've seen on the web)

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

MSMA says it will work on Johnsongrass or Dallisgrass so you should probably give it a try. There are some listed weeds which I found MSMA doesn't work all that well on. It works best when the temperature is high, so now and throughout the summer is when the best results can be had from MSMA. You'll know within a week if it's working or not. You may have to reapply in 2-3 weeks.
MSMA is the best thing I've found for postemergent control of crabgrass in Bermuda lawns. It will discolor your grass, but won't kill Bermuda as long as you mix it at recommended levels.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks. I'll make a run to Lowe's tonight.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.