Disease · Maize (corn)
Northern corn leaf blight: before flowering, it hurts
Exserohilum turcicum
Long grey spots that start low and climb. We fly the maize and mark the areas where you should check the leaves on foot.
We have not flown this problem ourselves yet. We work it out with you, on your field.
The problem
Cigar-shaped spots
It is a fungus of maize (corn) and sorghum, also called turcicum leaf blight. First thin tan streaks appear along the veins; then long lesions, grey or tan, shaped like a cigar. They start on the lower leaves and climb. In heavy attacks the leaf looks scorched by frost.
It likes moderate temperatures, with rain, dew or irrigation wetting the leaf for several hours. It overwinters in maize residue left on the surface.
How it works
A flight to know where to look
1
We fly the maize
Before flowering, when the weather is damp and mild.
2
We send you the map
Areas where the leaf looks drier or more spotted than the rest, so you can go and check them.
3
You check on foot
The lesions are confirmed up close. Isolated lesions are only visible flying very low, a few metres up.
Where it shows up
Where it shows up
- Maize (corn)
Also in seed maize (seed corn) and silage maize, where healthy leaf is worth even more.
What farmers ask us
Leaf blight: your field questions
Why does it come back every year?
Because it overwinters in maize residue. One or two years out of maize, and burying the residue, reduce the amount of fungus.
How do I tell it from other spots?
By the long lesion, grey or tan, shaped like a cigar. Even so, from a distance it can be mistaken for other diseases.
What do I do for next year?
Choose hybrids with some resistance if the field has a history of it, and rotate the crop.
Know someone this would help?
Send them this page. If they have northern corn leaf blight in their fields, you save them some searching.