Grapevine cultivar variation to pruning wound protection by <em>Trichoderma</em> species against trunk pathogens

Abstract

Using Trichoderma species to protect grapevine pruning wounds from trunk disease pathogensis one of the options available for managing grapevine trunk diseases. The growth and persistence of Trichoderma species in the pruning wound and the resulting control effect may depend on intrinsic wound factors and hence may vary between cultivars. Cultivar variability to pruning wound protection by Trichoderma species was evaluated in eight wine grape (Cabernet Sauvignon, Chardonnay, Chenin blanc, Colombar, Merlot,Pinotage, Sauvignon blanc and Shiraz) and four table grape (Prime, Red Globe, Thompson Seedless andVictoria) cultivars. Two strains of Trichoderma atroviride (USPP-T1 and USPP-T2) separately or in combinationand Eco 77® a registered pruning wound biocontrol agent based on T. harzianum, were applied to fresh pruning wounds of spur-pruned wine grapevines and cane-pruned table grapevines. Trichoderma spp. and a variety of trunk pathogens, Phaeomoniella chlamydospora and species of Phaeoacremonium, Phomopsis, Botryosphaeriaceae and Diatrypaceae, were isolated from the pruning wounds eight months after treatment. Significant treatment × cultivar interactions (P 0.50;P<0.05) though not in Chardonnay (r=0.37; P=0.11), Pinotage (r=-0.12; P=0.62), Sauvignon blanc (r=0.26;P=0.26) and Victoria (r=0.29; P=0.22). It was concluded that the wound protection effect of Trichoderma spp.is also dependent on the Trichoderma-grapevine interaction and is not only due to the suppressive effect of Trichoderma spp. on the pathogens.

Keywords

• Grapevine
• bio-control
• Phaeomoniella chlamydospora
• Phaeoacremonium
• Phomopsis
• Botryosphaeriaceae