WINETECH Technical Yearbook 2020

and they found that application during the rehydration stage was best to reduce fungal infections. Also, that application to the basal callus followed by soil drench- ing improved root quality and increased the number of certifiable vines. In British Columbia, novel Trichoderma isolates were collected in the field and screened for their potential to protect pruning wounds challenged with D. seriata and N. parvum conidia. Treatment combinations of the best three Trichoderma isolates reduced pathogen re-isolations by 100% from 1 day to 21 days after pathogen application. This indicates the time needed for the biocon- trol agent to establish on the wound. In an overview management presentation by Dr Mark Sosnowski, he referred to the

‘Best practice management guide’ that can be sourced from the Wine Australia website (www.wineaustralia.com). This updated guide provides valuable management information to best manage trunk diseases. In Australia, the two major trunk diseases are Eutypa dieback and Botryosphaeria dieback. In this guide, a method is described as to how dieback can be visually monitored, as well as a decision tree as to how to go about deciding on retraining vines. A practical guide is also provided to execute remedial pruning. Several pruning wound products have been registered in Australia, including fungicides that can be applied by spray application. This provides growers with a choice of products that can be used. In South Africa, there needs to be a

help our understanding of the infection and growth of the biocontrol fungus in the vine. In general, the workshop provided a plat- form to communicate the latest findings with regard to trunk diseases on grape- vines world-wide. The wealth of knowledge gained will aid our local efforts to study and develop effective management strategies for trunk diseases on grapevine.

greater effort from producers and industry that will motivate chemical companies to execute registration trials with prospective products. From our own research, we presented our latest findings on the use of Trichoderma atroviride in nurseries for the management of black foot disease. Different application methods and also different products were tested over a two-year period. Applying Trichoderma atroviride as a dry prod- uct on wet bases of callused vines before planting, gave the best establishment of this biocontrol fungus on the bases of the vines assessed after eight months. Also, a fluorescent isolate of Trichoderma atro- viride was developed, which can be used in the laboratory on potted vines. This will

For more information, contact Lizel Mostert at lmost@sun.ac.za or Francois Halleen at halleenf@arc.agric.za.

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