Plant pathologist studies disease in flooded and row rice

Kyle Peveto, Morgan, Johnny W.

Over the past two rice-growing seasons, LSU AgCenter plant pathologist Trey Price has begun to research diseases common to both flooded and upland rice, also known as row rice.

The diseases being researched include sheath blight, kernel smut, leaf blast and salt toxicity.

To study sheath blight, over the 2020 and 2021 seasons, research plots were established at the AgCenter Macon Ridge Research Station near Winnsboro. Multiple varieties, including Jupiter, CL163, Cheniere, CLL16 and RT7521, were planted and grown under upland and flooded conditions with 14 total trials.

For the study, Cheniere, CLL16 and RT7521 were inoculated with Rhizoctonia solani to ensure sheath blight development. The test plots were treated using 11 different fungicide applications, while the control plots were left untreated.

These fungicides were applied on the test plots at these amounts: Amistar Top (12.5 fluid ounces per acre), Elegia (22 fluid ounces per acre), Flint (4 fluid ounces per acre), Quadris (12 fluid ounces per acre), Quilt Xcel (22 fluid ounces per acre), Stratego (5.5 fluid ounces per acre), Sercadis (17.5 fluid ounces per acre), Tilt (8 fluid ounces per acre), Excalia (2.5 fluid ounces per acre), Artisan (40 fluid ounces per acre) and Flint (4 fluid ounces per acre) plus Tilt (8 fluid ounces per acre).

Salt damage in rice fieldjpg

All the tested fungicides resulted in lower sheath blight severity when compared to the nontreated control, Price said. Some fungicides performed better when checked later in the season.

When the plots in flooded conditions were checked in August, all the fungicides except for Quadris significantly reduced sheath blight compared to the control. Later in the study, in September, the plots treated with Elegia, Flint, Sercadis, Excalia and Artisan showed significantly lower sheath blight severity than the control.

All the upland plots treated with fungicide also showed lower sheath blight severity in mid-August. In early September, the plots treated with Elegia, Flint, Stratego, Sercadis, Excalia and Artisan had significantly lower sheath blight than the nontreated control.

For 2022 Price plans to continue to study the fungicide test at Macon Ridge.

During the 2020 and 2021 seasons, Price worked with AgCenter rice breeder Adam Famoso in variety development.

“We’ve managed nine variety trials containing conventional, Clearfield and Provisia lines for the breeding group,” Price said.

Plans are to continue this collaboration in the future.

Over the past two seasons, Price also worked with AgCenter plant geneticist Prasanta Subudhi to test salt-tolerant lines for salt toxicity at Macon Ridge.

“A site far removed from our traditional rice fields was selected where access to salty well water could be achieved,” Price said.

Total salts in the main irrigation well ranged from 2,100 to 2,700 parts per million with chloride values as high as 550 parts per million — levels that are considered very high for rice production, Price said.

In 2020, the study focused on six salt-tolerant lines. No foliar symptoms of salt toxicity were observed during the growing season, Price said. In 2021 nine entries were provided for the study, and results are not yet available.

For 2022 Price plans to continue to test the salt-tolerant lines.

12/15/2021 6:22:57 PM
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