Unusually heavy and prolonged rains have drenched Florida this year. The soils in citrus groves and blueberry groves across the state were saturated for weeks or months.

“I've never seen anything like it in my 20 plus years in the industry, and the true ‘old timers’ have not either,” said Mark White with Growth Products, Ltd.

When soils become saturated, oxygen is crowded out and anaerobic bacteria gain a foothold. These anaerobic bacteria, which produce a foul-smelling rotten-egg odor in the soil, harm the roots of trees and shrubs.

In as little as four or five days in drenched and anaerobic soils, a tree's root systems can begin to die back and shrink. The damage to the roots and—consequently—to the tree can be considerable. Symptoms of damage include leaf yellowing and leaf drop, fruit drop, wilting, and canopy die-back, White explained. 

“We couldn't stop the rain this summer, but we can minimize the damage from excessive rain to groves, fields, and crops by carefully managing and tweaking nutrient applications from here on out. In fact, our best window of opportunity for reversing damage is now, as new feeder roots begin to emerge as the soil dries and returns to more normal conditions,” he said.

White is recommending a heavy dose of a phosphite product, heavier than he would normally recommend at this time in the year, “but the heavy rains and unique environmental conditions demand an adjustment such as this,” in his opinion.

He said, “The phosphite reduces plant stress caused by environmental extremes, including temperature extremes, drought, and excess rain and flooding. Researchers don't precisely know how phosphite reduces harmful stress effects in plants, but it may have to do in part with the thickening and fortifying of the plants' cell walls. Regardless of the mechanism, the positive effects are real and measurable.”

He concluded by suggesting, “Any time you reduce the symptoms of stress, you reduce the symptoms and the effects of citrus greening (HLB). By making a late-season application of in citrus groves, you'll reduce the stress brought on by the anaerobic soil conditions of this summer. You will also help reduce fruit drop. In Valencias in particular, which are a late-season crop, you will improve fruit size.”

The phosphite product White is promoting is "TKO" Phosphite 0-29-26 from Growth Products (800) 648-7626.