Grass: brown spots; Tree: Honeylocust shedding

Asked June 12, 2018, 5:35 PM EDT

Hi, I'm having problems with both my grass and my Honeylocust. Perhaps you can shed some light on what's taking place. Grass. About 5 days ago our backyard grass developed a dozen brown spots about 8-12 inches in oblong diameter. I believe they occurred within a 24 hour time period. There's very little thatch on the soil, no fuzzy stuff on the spots, no slime and no surface bugs. I fertilized with a pre-emergent fertilizer about 3 weeks ago. The grass is mostly in the shade beneath our Honeylocust. Photos attached. Tree. For maybe a month our Honeylocust (possibly a Shademaster; thornless, no pods) dropped very tiny (1/16") organic matter that fell in abundance causing a twice daily need to blow off the deck (to avoid mashing the stuff onto the surface). At the same time there appeared innumerable tiny (1/8") green/yellow bugs under and around the tree (in my hair...). About 5 - days ago, overnight all the shedding stopped and the bugs disappeared. Overnight! Shortly thereafter the tree began to drop what looks like hundreds of tips of new growth (no leaves) and now some leaf clusters are starting to drop and the individual leaves appear stressed. My Googling may suggest Honeylocust Plant Bug. Have you any ideas? I've attached a couple of photos. Thank you, Michael Kehoe 612-722-7172

Hennepin County Minnesota

3 Responses

The grass looks very much like pesticide drift. Some of the spots on the leaves look like it too. Did you or your neighbor use any chemicals lately or have lawn treatments? Without a picture of the insect you describe it is not possible to accurately id the insect. There does seem to be some evidence of chewing insects on the branches and leaves. Four line plant bugs have been active lately. (They are green and yellow.). See:https://www.extension.umn.edu/garden/insects/find/fourlined-plant-bugs/. If they are honey locust plant bugs they would be feeding for at least a month. Their disappearance could be explained by pesticide drift. Trees can loose up to 80% of their leaves and still survive, See:https://www.mortonarb.org/trees-plants/tree-and-plant-advice/help-pests/honey-locust-plant-bug. If this is a high value tree you may want to have an onsite consultation with a certified arborist. They may suggest treating the tree to prevent overwintering of pests such as the honey locust plant bug if that is the problem.

Mary, thank you for your reply. Today I noticed my tomato plants had white fuzzy stuff with a white dot similar to a very small grain of rice. With a magnifying glass, I took a closer look at some of my fallen Locust leaves and I now see some indications of similar white fuzzy material and the white dot in among it. I also noticed some of the organic matter that had fallen in abundance from the locust tree had stuck to a nearby plastic shed. It appears to me that the organic matter may be leaf pods (?) just starting to open before they fell. And the curling new growth shown in a picture from yesterday looks like it may be a leaf stem (?) that fell once the leaf pods had all released leaving the stem bare. I don't see anything on the underside of the leaves, no casings, black spots, etc. There's also been no eating of the edges of the leaves. Does this help narrow down what's happening? Photos are attached. Thanks.

Thanks for the additional pictures. The white fluffy material appears to be cottonwood/poplar seeds. It can travel and get caught in other trees. See:http://www.treetopics.com/populus_deltoides/gallery1.htm The small bud like material appears to be a bud from the honey locust flower or other flowering tree like the cottonwood. Dropping flower buds would be normal for a honey locust tree as the thornless varieties are often sterile. And honey locust trees are known to drop branches in windy conditions. They are also known to have branches die back in winter. If only a few leaves and branches are affected, it should be fine. If you have concerns that the tree continues to decline, you may want to have an onsite consultation with a certified arborist. Also the brown spots on your lawn could be fertilizer burn...too much nitrogen. If you mixed the fertilizer on the lawn or cleaned out the equipment on the lawn, it could explain the patches. Additional information about lawn disease that show up as patches can be found at the following website. (I do not think this is the problem given the short timeframe in which the patches developed.) See:http://www.extension.umn.edu/garden/turfgrass/pests/turf-patch-diseases/index.html