Pythium and related species on blueberry plants in South Africa

Abstract

The blueberry industry is one of the successful and expanding agricultural cropping systems in South Africa. As a result of this growth, research into identifying plant disease agents has become increasingly important, yet there are relatively few scientific reports published on the subject in the country. The aim of this study was to identify the causal agents of stunting and leaf scorch on blueberry plants and evaluate their pathogenicity. Root samples were collected from a commercial southern highbush blueberry planting in North West, South Africa. The resulting isolates were identified based on sequence data from the rDNA-ITS. Three Pythiaceae were identified including Globisporangium ultimum var. sporangiiferum, Globisporangium splendens and Pythium aphanidermatum. Results of pathogenicity trials showed that the isolated species were able to cause disease on 40% of the plants. This is the first official report for G. ultimum var. sporangiiferum in South Africa and the first report of G. ultimum var. sporangiiferum and P. aphanidermatum from blueberry plants.