September 2020 Disease Reports from the UNL Diagnostic Clinic

September 2020 Disease Reports from the UNL Diagnostic Clinic

The following diseases and pests were reported in samples submitted to the UNL Plant and Pest Diagnostic Clinic from August 16 through September 2, 2020.

Soybean

  • Central District – Bacterial Pustule, Brown Spot, Frogeye Leaf Spot, Septoria Brown Spot, Sudden Death Syndrome
  • East District – Bacterial Pustule, Brown Stem Rot, Frogeye Leaf Spot, Septoria Brown Spot, Stem Canker, Sudden Death Syndrome
  • North District – Bacterial Blight, Bacterial Pustule, Stem Canker, Sudden Death Syndrome
  • Southeast District – Bacterial Pustule, Brown Stem Rot, Dectes Stem Borer, Frogeye Leaf Spot, Phyllosticta Leaf Spot, Septoria Brown Spot, Sudden Death Syndrome
  • South District – Frogeye Leaf Spot, Septoria Brown Spot, Sudden Death Syndrome
Interveinal chlorosis
Photo 1. Interveinal chlorosis on upper soybean leaves can be caused by different diseases. Cutting stems is necessary to determine the cause.
Split stem of soybean
Photo 2. Split stem of soybean showing brown streaking of vascular tissue that is common with Sudden Death Syndrome. The center pith remains healthy.
Split stem of soybean
Photo 3. Split stem of soybean showing rotten, segmented pith and discolored vascular tissue that is common with Brown Stem Rot.
Split stem of soybean
Photo 4. Split stem of soybean showing brown frass and sawdust from Dectes Stem Borer. Does not cause interveinal chlorosis, but browning of pith may be confused with Brown Stem Rot. Cream-colored borer is noticeable at the base of the cut portion of stem.

Corn

  • Central District – Anthracnose Leaf Blight, Bacterial Leaf Streak, Common Rust, Diplodia Leaf Streak, Eyespot, Fusarium Leaf Scorch, Goss’s Wilt, Gray Leaf Spot, Maize Chlorotic Mottle Virus, Northern Corn Leaf Blight, Physoderma Brown Spot, Southern Corn Leaf Blight, Southern Rust
  • East District – Anthracnose Leaf Blight, Bacterial Leaf Streak, Common Rust, Diplodia Leaf Streak, Eyespot, Gray Leaf Spot, Northern Corn Leaf Blight, Physoderma Brown Spot, Southern Rust
  • North District – Bacterial Leaf Streak, Common Rust, Gray Leaf Spot, Northern Corn Leaf Blight, Southern Rust
  • Northeast District – Bacterial Leaf Streak, Common Rust, Common Smut, Goss’s Wilt, Gray Leaf Spot, Northern Corn Leaf Blight, Northern Corn Leaf Spot, Physoderma Brown Spot, Southern Rust
  • South Central District – Anthracnose Leaf Blight, Bacterial Leaf Streak, Common Rust, Eyespot, Fusarium Leaf Scorch, Goss’s Wilt, Gray Leaf Spot, Northern Corn Leaf Blight, Physoderma Brown Spot, Southern Corn Leaf Blight, Southern Rust
  • Southeast District – Bacterial Leaf Streak, Common Rust, Goss’s Wilt, Gray Leaf Spot, Northern Corn Leaf Blight, Northern Corn Leaf Spot, Physoderma Brown Spot, Purple Leaf Sheath, Southern Rust
  • Southwest District – Southern Corn Leaf Blight, Gray Leaf Spot, Southern Rust

Alfalfa

  • Southeast District – Alfalfa rust, Summer black stem

Resources

Find more information and photos about each of these diseases in the Crop Disease Management section of CropWatch for Wheat, Soybean, and Corn. If you'd like to submit a sample to the clinic for diagnosis, check this CW story, Quality Samples Lead to Better Diagnosis, for tips on packaging and sending samples.

Visit the Plant and Pest Diagnostic Clinic page in CropWatch for

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