Southern Rust spores have arrived in a three-county area of the Upper Texas coast and many growers in the region are now hoping for clear skies as corn slowly dries down before harvest commences in the weeks ahead.

The corn crop in Jackson, Wharton and Matagorda Counties has benefited from early spring rains followed by a drying period and more rain in May and early June. While the rains have helped plants develop, combined with moderate morning dews, it has created leaf moisture, a condition ripe for the growth of rust spores.

Dr. Thomas Isakeit, Professor and Extension Plant Pathologist for Texas AgriLife in College Station, reports early detection of Southern Rust along the Upper Coast first began to surface during the first week in June, but he says early signs on lower leaf corn appeared in late May. A period of dry weather this week, however, is keeping the Rust from spreading up the plant.

“Spores from the south, probably Southern Mexico, were carried by the wind until they found a home. Moist leafy material represents the perfect environment for the spores to germinate, and we are now seeing some Southern Rust move up the plants in these three counties,” said Isakeit.

Southern Rust has also been reported in Rio Grande Valley corn, though “not widespread” and under control because of dry weather.

Southern Rust is more common in Louisiana and around the coast to Florida, but because conditions must be just right for germination, it becomes a problem for coastal Texas growers about every five years or so. Isakeit says along the Upper Coast, rust is not widely spread across the region and can be found in one field and not the next.

“It has a lot to do with the hybrids planted in our test plots and in the fields. Some hybrids are more resistant to Southern Rust than others. The same is true about how the final yield will be for infected corn. That’s a variable we don’t have an answer for currently. I know of one instance where an infected crop actually yielded better with the rust condition than other varieties in the same field. In other cases yields have suffered as much as 45 percent. But we need to conduct trials on the newer varieties of hybrids before we can determine which is best from a resistance standpoint,” he adds.