Biological control of Cylindrocarpon spp. on grapevine roots.

Those inoculated with Streptomyces sp. or with C. macrodidymum and Streptomyces sp. together, were healthy. SEM showed evidence of parasitism of C. macrodidymum conidia by Streptomyces sp.. Table 1: Potted Chardonnay vines 14 weeks after inoculation1. Root length (cm) Root rot 2Control 333 a 1.0 aC. macrodidymum 28 b 4.0 bC. macrodidymum plus Streptomyces sp. 258 a 1.0 aStreptomyces sp. 305 a 0.8 a1 ANOVA performed for data from 4 replicate pots; 2 0 = no disease symptoms; 1 = 1-25%; 2 = 26-50%; 3 = 51-75%; 4 = 76-100% root rot. Values within a column followed by the same letter are not significantly different based on l.s.d. (P = 0.05). Discussion:Streptomyces sp. was shown to be antagonistic towards Cylindrocarpon macrodidymum. Future work will further investigate parasitism and induction of plant degenes by the actinomycete.for 5th ASDS Melanie Weckert, National Wine and Grape Industry Centre, Charles Sturt University, Wagga Wagga, NSW12/11/08 (282 words)Biological control of Cylindrocarpon spp. on grapevine rootsStreptomyces sp. isolated from vineyard soil in Wagga Wagga, NSW, decreased vegetative growth of Cylindrocarpon liriodendri and Cylindrocarpon macrodidymum on potato dextrose agar. The actinomycete also demonstrated biocontrol activity against C. liriodendri in a long term Vitis vinifera cv. Chardonnay soil pot experiment. In order to study the interactions between the actinomycete and pathogenic fungus, a gnotobiotic pot experiment was conducted with Vitis vinifera var. Chardonnay rooted cuttings in sterile sand/peat. Materials and Methods Two-month old Chardonnay rooted cuttings were inoculated with Streptomyces sp. and then with Cylindrocarpon macrodidymum three weeks later. Four replicate uninoculated vines plus vines inoculated with C. macrodidymum alone; C. macrodidymum and Streptomyces sp. together; and Streptomyces alone were grown in enclosed pots in a glasshouse for 14 weeks. Results:The vines inoculated solely with C. macrodidymum were dead after 14 weeks.