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The P&PDL Picture of the Week
for 14 April 2003



Heat Stress & Corn Ear Development

Bob Nielsen, Department of Agronomy, Purdue University

Direct effects of extremely hot temperatures during pollination is not in my top 10 list of stress factors for Indiana corn fields. I usually downplay the direct effects of severe heat because Indiana usually does not suffer many days of truly stressful temperatures (100F or greater) during the growing season. For most Indiana situations, heat amplifies the direct effects of drought during pollination rather than directly affecting pollination itself.

Having said that, though, I had the occasion to observe the consequences of extreme heat and wind during pollination on a recent visit to Australia. These photos illustrate the leaf damage and near total arrest of ear development in an irrigated corn field in drought-stricken Queensland that had endured more than a few days of extreme (104F and greater) and dry searing winds during pollination.

Click on the small image to view a larger image.

Leaf death due to excessive hot
temperatures and dry winds

Kernel abortion resulting from
heat stress to plant
Kernel abortion resulting from
heat stress to plant

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Last updated: 10 April 2003/amd
The Plant & Pest Diagnostic Laboratory at Purdue University