Suppression of Citrus Young Tree Decline with Humus. J. A. Pinckard, Professor Emeritus, Department of Plant Pathology, Louisiana State University, Baton Rouge. Plant Dis. 66:311-312. Accepted for publication 12 August 1981. Copyright 1982 American Phytopathological Society. DOI: 10.1094/PD-66-311.

Citrus young tree decline, which has caused an average estimated 10% tree loss in Florida for the past several years, has been suppressed by addition of a special humus as a soil amendment to 12-yr-old Valencia orange trees. A 6-yr study showed an 82% recovery of affected trees in soil top-dressed once with 100 lb (45 kg) of humus. In a 5-yr study of yields, fruit was increased about 20% in a treated block of 400 trees. Yields declined approximately 28% in an adjoining untreated block of 900 trees. Use of the humus as a one-time topdressing to the soil under the leaf canopy of affected orange trees appeared to partially correct an unfavorable soil condition frequently associated with citrus growing on the sandy flatwoods and ridge soils of Florida.

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