UK Home Academics Athletics Medical Center Research Site Index Search UK

College of Agriculture Signature Logo Plant Pathology Header Image
  Diagnostic Images College of Ag Home Site Index Search People Help
                         
   
Corn
               

Note:
If you have a PopUp blocker
you may need to disable it
(in Internet Explorer,
go to Tools, Internet Options, Privacy
and uncheck the "Block pop-ups" choice)
or
choose "Allow Blocked Content..."
each time a pop-up is blocked (could get tedious).

    Choose from this list
or
scroll down the page
   

     
 
   
       

Send comments and questions to Paul Bachi,
Last Modified: 09-Oct-2012
Copyright © 2004, University of Kentucky, College of Agriculture, Department of Plant Pathology

       

Plant: Corn (Zea mays) (Poaceae) Back to List
Disease/Disorder: Gibberella stalk rot
Causal agent: Gibberella (teleomorph) Fusarium (anamorph) (fungus)
Signs: Perithecia of Gibberella are bluish black and superficial on stalk near nodes.
Symptoms: stalk rot
Total image number: 4

         
 
         
                           

Plant: Corn (Zea mays) (Poaceae) Back to List
Disease/Disorder: Diplodia leaf streak
Causal agent: Stenocarpella macrospora (fungus)
Signs: Pycnidia are seen immersed in the symptomatic leaf tissue.
Symptoms: tan, necrotic leaf tissue in fairly large oval spots similar in size to that seen with Northern corn leaf blight.
Total image number: 7

 

Back to List

         
                           

Plant: Corn (Zea mays) (Poaceae) Back to List
Disease/Disorder: 1- Stinkbug injury.
2- Damping-off and seedling blight caused by the fungus Pythium.
Causal agent: Stinkbug and Pythium sp. (fungus)
Signs: Oospores of Pythium sp.
Symptoms: With #1 there is symptomatic evidence of stinkbug feeding. With #2 incubation of hypocotyl and root tissue produced oospores (spore structures of the fungus) in the infected tissue (see four B&W micrographs).
Total image number: 8

 
 
 
                         

Plant: Corn (Zea mays) (Poaceae) Back to List
Disease/Disorder: Corn smut
Causal agent: Ustilago maydis (fungus)
Signs: Smut galls (the fungus itself) can be formed on any part of the plant from near the soil line to tassels, from seedlings to mature plants, but most commonly found on the ear.
Symptoms: see below
Total image number: 11

 
 
     
   
 
   
                         

Plant: Corn (Zea mays) (Poaceae) Back to List
Disease/Disorder: Crazy top
Causal agent: Sclerophthora macrospora (fungus)
Signs: none shown
Symptoms: The left-most image is of a plant that had its tassel replaced by a mass of leafy tissue.
As for the image of the very tall plant, this plant had no ears but that would not account for the plant's height; it is likely just a genetic mutation. The last two images on the right show a wrapping of the terminal leaves, which can be caused by a growth regulator.
Total image number: 4

           
 
           
                         

Plant: Corn (Zea mays) (Poaceae) Back to List
Disease/Disorder: Southern rust (suspected)
Causal agent: Puccinia polysora
Signs: The third image shows spores called "urediniospores".
The fourth image shows spores called "teliospores".
Symptoms: The disease resembles common rust but with some subtle differences. Most of the rust pustules or spots of rust can be found on the upper leaf surface and there shape is rounded as opposed to common rust where they are more elliptical. The rust spores themselves are yellowish to reddish-gold whereas those of common rust are more chestnut brown.
Total image number: 4

         
 
         
                         

Plant: Corn (Zea mays) (Poaceae) Back to List
Disease/Disorder: herbicide injury
Causal agent: 'glyphosate' ("RoundUp")
Signs: none
Symptoms: newly emerging corn with yellowed new leaf tissue. Seedlings were just poking through the soil when herbicide was sprayed, several days after planting.
Total image number: 4

         
 
         
                         
Plant: Corn (Zea mays) (Poaceae) Back to List
Disease/Disorder: Diplodia ear rot
Causal agent: Stenocarpella maydis (syn. Diplodia maydis)
Signs: The fungus is visible as white to gray mycelial growth over the husks and kernels. Globose or flask-shaped pycnidia containing olive to brown, two-celled conidia (5-6 x 25-20 um).
Symptoms: Symptoms often start at the base of the ear. The fungus is visible as white to gray mycelial growth over the husks and kernels. Infected ears are very light in weight and may be totally rotted.
Total image number: 9
         
 
         
                         
  Back to List
or
back to page with list of all crops