Control of Avocado Root Rot by Trunk Injection with Phosethyl-Al. J. M. Darvas, Plant Pathologist, Research Department, Westfalia Estate, P.O. Box 14, Duiwelskloof 0835, South Africa. J. C. Toerien, Agricultural Manager, and D. L. Milne, General Manager, Research Department, Westfalia Estate, P.O. Box 14, Duiwelskloof 0835, South Africa. Plant Dis. 68:691-693. Accepted for publication 9 February 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-691.

Excellent control of Phytophthora root rot was achieved on fully grown avocado trees by injecting phosethyl-Al twice a year at a rate of 0.4 g a.i./m² of canopy area. The treatment resulted in a significant reduction of Phytophthora cinnamomi incidence in the feeder roots. An increase in the aluminum content of the treated trees was observed. A negligible amount of phytotoxicity occurred on the foliage of some phosethyl-Al-injected trees. Metalaxyl injected at 0.028 g a.i. and pyroxyfur at 0.4 g a.i./m² of canopy area failed to control the disease.

Keyword(s): Persea americana.