Corn foliar diseases can have similar symptoms. See below for a refresher on 6 of the most common foliar diseases in Beck's marketing area. For help with a specific situation, or to learn more about management options, reach out to your local Beck's representative.

Corn foliar diseases can have similar symptoms. See below for a refresher on six of the most common foliar diseases in Beck's marketing area. For help with a specific situation or to learn more about management options, reach out to your local Beck's representative.

Begins on lower leaves and works its way up the canopy

Large (1 to 6 in.) elliptical lesions that form parallel to the leaf

Begin as greyish-green lesions which then turn tan; not restricted by leaf veins

Infested corn residue from the prior year(s)

Wet, humid weather that keeps the leaves wet for long periods

Can quickly cover the canopy (and impact yield) due to large lesion size

If inoculum is present, rotate to a non-host crop

Select for a hybrid with a good NCLB rating

Medium (0.5 to 2 in.) rectangular lesions

Normally seen starting two weeks prior to tassel

Hot and humid (80° F and above) and cloudy

Select for a hybrid with a good GLS rating

Begin as light green or yellow and turn to orange raised pustules

Typically found on the upper leaf surface and seldom on lower

Lesions can be on the husks and stalks in addition to the leaves

Lesions can form concentric circles around the darker original pustule

Inoculum survives the winter on corn in more southern locations and is carried north by wind

Can be found throughout the Corn Belt, but severe cases have been limited to the southern states

Severity depends on when Southern Rust arrives

Crop rotation and residue management are irrelevant because the inoculum does not overwinter

Damage is often more severe on later planting dates or late-maturing hybrid

Hybrids vary in resistance to Southern Rust

Begin as light green or yellow and turn to brick-red raised pustules

Lesions can be on husks and stalks in addition to leaves

Normally seen between the V6 and R2 growth stages

Humid with moderate temperatures (60 to 77°F)

Younger leaf tissue is more susceptible to rust, so later-planted corn may show higher levels of rust than early-planted corn

Severity depends on when common rust arrives

Most modern hybrids have adequate resistance to common rust

Very small (1/8 to 1/4 in.) purple or black circles

Lesions found on the leaves in the middle of the canopy

Usually forms a band along the leaf midrib, but it can also form on the stalk and leaf sheath

Overwinters in infested corn residue from prior year(s)

This water-loving pathogen can also survive in the soil

Typically, symptoms first appear in mid to late vegetative stages. The lesions can be mistaken for Common Rust

Prolonged wet periods early in the season with warm temperatures (75 to 85°F)

Infection takes place when the whorl is full of water for an extended period of time

Corn plants become more resistant in the late vegetative growth stages

Disease has historically been of minor importance

Large (1 to 6 in.) elliptical lesions with small black freckles\

Lesions appear wilted and water-soaked and start off as dark green to black and eventually turn tan