Late Season Decline of Corn
Late season decline (LSD) is a new disease of corn that was first observed in 2020 and is believed to be caused by a new species of bacteria in the genus Pantoea. Plants can be infected by this bacterium at any growth stage. Early infections appear on leaves as light green, elongate, slightly translucent, and non-chlorotic lesions with non-wavy margins. The edges, or margins, of lesions can appear water-soaked under wet or humid conditions such as after rain or irrigation. Foliar symptoms are distinct and can be used to aid in diagnosis.
Foliar symptoms of late season decline disease on corn during early stages of reproductive growth.
Ken Obasa
Foliar symptoms of late season decline disease on corn during early stages of reproductive growth.
Ken Obasa
During the reproductive growth stages, the incidence and severity of the symptoms increases significantly. Foliar lesions often get larger, coalesce, and turn necrotic, resulting in leaf blight that usually progresses from leaf tips towards the base of affected leaves. This stage of the disease can progress rapidly, and previously green stands can turn necrotic and appear blighted within a week.
Foliar symptoms of late season decline during later stages of reproductive growth.
Ken Obasa
Foliar symptoms of late season decline during later stages of reproductive growth.
Ken Obasa
Stunting has also been observed in several corn hybrids infected by this bacterium. Additionally, infection can delay the onset of reproductive growth. Affected plants may have stalk rot from the infection of the vascular tissues, and this often goes undetected, predisposing affected plants to lodging. Other symptoms associated with the disease include aborted ears, small and poorly developed ears having few or no kernels that are often malformed, hypertrophied or swollen in appearance. The disease can significantly reduce grain yield and quality.
It is not known how this organism arrived in the United States, or Texas. Further research is needed to understand more about this new disease. Management information is not currently available. Do not use fungicides to manage bacterial diseases.
Prepared and reviewed by Ken Obasa, Texas A&M University.
Foliar symptoms of late season decline disease on corn during early stages of reproductive growth. Ken Obasa.
Foliar symptoms of late season decline disease on corn during early stages of reproductive growth. Ken Obasa.
Foliar symptoms of late season decline during later stages of reproductive growth. Ken Obasa.
Foliar symptoms of late season decline during later stages of reproductive growth. Ken Obasa.
Foliar symptoms of late season decline during later stages of reproductive growth. Ken Obasa.
Stunted growth of infected corn stands. Ken Obasa.
Stalk rot-induced lodging of infected corn stands. Ken Obasa.
Gallery images courtesy Ken Obasa.
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