LSU AgCenter rice specialist Johnny Saichuk is on the trail of a mystery, and he's asking farmers for clues.

“Nobody seems to be able to get a good hold on it,” Saichuk said. “In fields afflicted with the ‘mystery disease,’ areas of the field usually are completely killed — or at least thinned out severely. Plants also are shorter, less healthy and have bronzed or rust colored lower leaves.”

Saichuk said some rice fields have been showing symptoms similar to bronzing, which usually is corrected with an application of zinc. “But most of these fields don't respond to zinc,” he said.

The problem also resembles some aspects of potassium deficiency, he said, but that's not always the case. “Some fields still will respond to potassium and some will not,” the LSU AgCenter expert said.

Saichuk also said he has ruled out hydrogen sulfide toxicity.

So far, the only thing that seems to remedy the problem is draining an affected field, which leads Saichuk to believe the problem is somehow related to anaerobic conditions. “The introduction of oxygen to the soil will alleviate the problem,” he said.

The condition has been found only in silt loam soil, according to Saichuk, who said, “At least no one can recall the condition occurring in clay or clay loam soils.”

So far, the mystery disease has surfaced in Vermilion, Acadia and Jefferson Davis parishes, Saichuk said. But one piece in the puzzle indicates that it hasn't been found in rice varieties of Wells or Francis, according to Saichuk.

The LSU AgCenter specialist said farmers who have this problem should contact their LSU AgCenter Extension office to pass along such information as: soil type; when fertilizer was applied; whether the field was worked dry or in the water; if the field was worked in the water, when fertilizer was applied in relation to working the field; whether the problem occurs in the top paddies or bottom; whether it occurs in deep areas or high spots; and whether or not it occurs near water inlets?

“It's very frustrating, but the more input people give us, the better off we'll be,” Saichuk stressed.


Bruce Schultz writes for the LSU AgCenter.