Crop Diseases Confirmed by Plant & Pest Lab June 15-27

Crop Diseases Confirmed by Plant & Pest Lab June 15-27 June 29, 2017

Holcus spot of corn
Figure 1. (left) Typical symptoms of Holcus spot caused by Pseudomonas syringae pv syringae: light tan to white round spots that look similar to minor damage from herbicide drift from cell membrane disruptors, such as gramoxone (like Paraquat). (right) More severe symptoms of Holcus spot. It is important to not mistake this disease for a fungal leaf disease as fungicides will not be effective against this bacterial pathogen.

The following diseases were reported in samples submitted to the UNL Plant and Pest Diagnostic Lab June 15 to June 27.

Map of Nebraska crop reporting districts
Figure 1. Reporting districts (View larger)

Wheat

East District – Septoria leaf spot, leaf rust, stripe rust, bacterial stripe/black chaff

Southwest District – Wheat streak mosaic virus, Septoria leaf spot, leaf rust, bacterial stripe/black chaff

Northwest District – Wheat streak mosaic virus, Septoria leaf spot, leaf rust

Soybean

East District – Pythium damping off

Southeast District – Rhizoctonia damping off

Central District – Rhizoctonia damping off

Corn

Southwest District – Holcus spot

East District – Pythium damping off

Southeast District – Rhizoctonia damping off, Holcus spot

Central District – Fusarium crown and stem rot damping off

South District – Fusarium crown and stem rot, Bacterial leaf streak, common rust, Holcus spot

Hops

East District – Downy mildew

Resources

Find more information and photos about each of these diseases in the Crop Disease Management section of CropWatch for Wheat, Soybean, and Corn.

Visit the Plant and Pest Diagnostic Clinic page in CropWatch for

  • information on how to submit crop and pest samples,
  • sample submission form, and
  • a fee schedule for diagnostic services.