Physoderma brown spot of corn

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

click image to zoomPhysoderma brown spot lesions on a corn leaf. Physoderma brown spot, caused by the pathogen Physoderma maydis, is making an appearance in Illinois cornfields. In some cases, severe symptoms have been observed. Symptoms appear as small, round to oblong spots on the leaves, generally occurring in bands. Symptoms also can occur on the leaf sheath as dark purple circular lesions, which may be confused with "purple leaf sheath." If there are no lesions on the leaves, then the leaf sheath symptoms likely are caused by purple leaf sheath. Purple leaf sheath occurs when pollen grains are trapped between the leaf sheath and stalk and are colonized by saprophytic fungi; the results are cosmetic only, causing no damage.

click image to zoomDark circular lesions of Physoderma brown spot on a corn leaf sheath. Infections by P. maydis generally take place in the leaf whorl or where free moisture is present. A quick scan of fungicide labels reveals that Headline and Headline AMP list Physoderma brown spot as a target disease. Although the disease symptoms may be somewhat severe in some fields, applying a foliar fungicide now may not be beneficial. Most affected cornfields would be at the stage where the leaf whorl is no longer present, so the likelihood of new infections is considerably decreased (in other words, noninfected tissue would not necessarily need protection from a fungicide because new infections are unlikely). In fields with severe symptoms this season, the best management practices are to rotate to a nonhost crop next year and plant a resistant hybrid (if available) the next time corn is grown in those fields. To confirm whether you have Physoderma brown spot in your field, send samples to the University of Illinois Plant Clinic.

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


Made of high quality 304 stainless steel, the Quickveyor is one of the strongest trailers on the market. It’s belt ... Read More

View all Products in this segment

View All Buyers Guides

Feedback Form
Feedback Form