Holcus leaf spot of corn in southern Indiana

decrease font size  Resize text   increase font size       Printer-friendly version of this article Printer-friendly version of this article

Figure 1. Yellow and white lesions with a water-soaked halo are indicative of holcus leaf spot in corn. Corn fields in southern Indiana are exhibiting symptoms of holcus leaf spot, a disease caused by the bacterium Pseudomonas syringae pv. syringae. Infected plants will have round, discrete lesions that are initially pale yellow to white and then enlarge and turn gray or brown.

Lesions have a water-soaked halo and on certain hybrids, the margin of the lesion may appear brown or purple (Figure 1). Lesions are typically distributed from the center to the tips of leaves (Figure 2). Holcus leaf spot can easily be confused with symptoms caused by herbicide drift or injury. To determine if the symptoms are caused by disease or an abiotic disorder, it may be necessary to submit a sample to a diagnostic lab where it will be checked for the presence of the bacterium.

Figure 2. Holcus leaf spot observed on centers and tips of leaves. Holcus leaf spot development is favored by warm temperatures (mid 70s-to mid-80s) and rainy, windy weather. Although rain has been scarce in Indiana, most symptoms appeared after rains that occurred at the end of May. The bacterium enters the plant through wounds or through stomates, and is not known to spread from infected leaves to healthy leaves. The bacterium will overwinter in infected residue, and also on other grass species, including weeds.

Holcus leaf spot is not a common disease in Indiana, and is not known to limit yield. Although the disease may cause concern based on symptom appearance, no in-season treatment is available or necessary. Fungicide applications will not have efficacy against this bacterial disease.


Buyers Guide

Doyle Equipment Manufacturing Co.
Doyle Equipment Manufacturing prides themselves as being “The King of the Rotary’s” with their Direct Drive Rotary Blend Systems. With numerous setup possibilities and sizes, ranging from a  more...
A.J. Sackett Sons & Company
Sackett Blend Towers feature the H.I.M, High Intensity Mixer, the next generation of blending and coating technology which supports Precision Fertilizer Blending®. Its unique design allows  more...
R&R Manufacturing Inc.
The R&R Minuteman Blend System is the original proven performer. Fast, precise blending with a compact foot print. Significantly lower horsepower requirement. Low inload height with large  more...
Junge Control Inc.
Junge Control Inc. creates state-of-the-art product blending and measuring solutions that allow you to totally maximize operating efficiency with amazing accuracy and repeatability, superior  more...
Yargus Manufacturing
The flagship blending system for the Layco product line is the fully automated Layco DW System™. The advanced technology of the Layco DW (Declining Weight) system results in a blending  more...
Yargus Manufacturing
The LAYCOTE™ Automated Coating System provides a new level of coating accuracy for a stand-alone coating system or for coating (impregnating) in an automated blending system. The unique  more...
John Deere
The DN345 Drawn Dry Spreader can carry more than 12 tons of fertilizer and 17.5 tons of lime. Designed to operate at field speeds up to 20 MPH with full loads and the G4 spreader uniformly  more...
Force Unlimited
The Pro-Force is a multi-purpose spreader with a wider apron and steeper sides. Our Pro-Force has the most aggressive 30” spinner on the market, and is capable of spreading higher rates of  more...
BBI Spreaders
MagnaSpread 2 & MagnaSpread 3 — With BBI’s patented multi-bin technology, these spreaders operate multiple hoppers guided by independent, variable-rate technology. These models are built on  more...

Comments (0) Leave a comment 

e-Mail (required)


characters left

Declining Weigh Blending System

Ranco Declining Weigh (DW) is the standard in fertilizer blending because of the speed and accuracy of the blending process. ... Read More

View all Products in this segment

View All Buyers Guides

Feedback Form
Feedback Form