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Disease Note

First Report of Guava Rapid Death Syndrome Caused by Septofusidium sp. in South Africa. N. M. Grech, Citrus and Subtropical Fruit Research Institute, Nelspruit, Republic of South Africa. Plant Dis. 69:726. Accepted for publication 22 February 1985. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-726e.

A disease causing rapid wilt of guava (Psidium guajava L.) was first noticed in 1981 in the Malelane area of eastern Transvaal and has since appeared in eight other localities, affecting approximately 12% of the regionís production. Symptoms are chlorosis, partial defoliation, and eventual wilting. During the early disease stages, water uptake is reduced and postpruning flush emergence delayed. A fungus belonging to the genus Septofusidium was consistently isolated from diseased and dead trees. The pathogen was primarily soilborne, infecting the root system. Wood discoloration was apparent only after tree death. Kochís postulates were fulfilled in the field and laboratory. Infection studies indicated that the fungus is a wound pathogen that migrates after tree death to the outer tissues and sporulates on the roots and trunk. Amorphous materials plugging lateral pits of xylem were observed by scanning electron microscopy. Screening of guava cultivars for resistance has begun, but tolerance to Septofusidium has not been found as yet, and control has been limited to eradication procedures.