JenREES 7/25/21

Last week I heard several mention close calls on gravel roads. Please, slow down/stop before crossing unmarked intersections, fully stop at marked ones, and please remind young people of this too.

Crop Update: Keep watching silk clipping on corn that’s pollinating; rootworm and Japanese beetles clipping silks to ½” long triggers treatment thresholds. Southern rust was found in Nemaha and Greeley Counties last week from two samples at low incidence and severity. You can view updates at: https://corn.ipmpipe.org/southerncornrust/. Consultants and farmers with suspect samples are welcome to get them to me as in the past, or send to the Plant and Pest Diagnostic clinic in Lincoln. I’ve only seen gray leaf spot on the lowest leaves of fields last week so far, so disease is currently very low.

South Central Ag Lab Field Day: Reminder of this field day near Clay Center this week on July 28th which will cover nutrient, insect, disease, and weed management topics in addition to irrigation, cover crops, and biomass ones. There was a press release from UNL that had the wrong date, so just want to make sure those in the area interested in attending are clear that this will be held on July 28th from 8:45 a.m.-4 p.m. (Registration at 8:30). More details and registration at: https://enrec.unl.edu/2021scalfieldday. Walk-ins are also welcome; we just ask for pre-registration to aid in meal planning purposes.

Workshops on ag land management, leasing, carbon credits: Nebraska Extension and the University of Nebraska-Lincoln’s Center for Agricultural Profitability will host a land management workshop. It will offer updated leasing information relevant to landlords and tenants, including the latest financial trends in Nebraska agriculture, updated land values and cash rental rates for the state, strategies for equitable leasing and farm succession considerations. The latest information on carbon credit contracts for ag producers and landlords will also be discussed. The presentations will be led by Jim Jansen, an extension educator and agricultural economist, and Allan Vyhnalek, an extension educator specializing in farm and ranch transition and succession. The meeting is free to attend with meal sponsored by People’s Company, but registration is required. Locations include:

  • July 28, 10:30-1:30 p.m., Extension Office, Columbus, Reg. 402-563-4901.
  • Aug. 2, 10:30-1:30 p.m., Fairgrounds, Auburn. Reg. 402-274-4755.
  • Aug. 3, 10:30-1:30 p.m., College Park, Grand Island. Reg. 308-385-5088.
  • Aug. 17, 10:30-1:30 p.m., Extension Office, Lincoln. Reg. 402-441-7180
  • Aug. 18, 9-Noon, Extension Office, Wilbur, Reg. 402-821-2151

Leaf Drop in Trees: Still receiving questions on this. For leaves such as Linden and Birch trees that have a lacy appearance of feeding on them, this is due to Japanese beetles. We hopefully are on our last week of them. For crabapple, flowering pear, ash, maples whose leaves are turning yellow/brown and dropping, this is due to fungal diseases and we wouldn’t recommend you do anything for this either. Next week I’ll talk about iron chlorosis and treatments for trees.

Brown Leaves on Oak Trees: Browning on leaf margins of individual leaves is anthracnose, which is a common fungus of shade trees. We don’t recommend that you do anything for this.

Anthracnose on oak.

The past few years around fair time, we’ve seen oak trees (but sometimes others such as hackberry, honeylocust, elm, linden) that get a cluster of brown leaves towards the ends of branches. This damage is caused by twig girdlers or twig pruners, different types of beetles. Basically, the adult beetles chew a circle in the bark between where the old and new wood occurs on a twig. This girdles the twig, cutting off the water and nutrient supply causing its death. Eggs are then deposited and larvae hatch, tunnel, and survive in the dead twigs. Twigs girdled by any of these insects may stay attached to the main branch for several weeks or be broken out of the tree by wind. Tunneling in the twigs may not be evident in the fall if twigs fall out of the trees before the insect eggs have hatched. Mature trees with heavy infestations can look bad, but the damage isn’t a serious health problem to the tree and no chemical control is recommended. You can burn or discard infected twigs in the fall and spring that contain developing larvae to minimize the impacts for the future.


About jenreesources

I'm the Crops and Water Extension Educator for York and Seward counties in Nebraska with a focus in irrigated crop production and plant pathology.

Posted on July 25, 2021, in JenREES Columns, Trees and tagged , , . Bookmark the permalink. Leave a comment.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: