The application of Trichoderma species on grapevine pruning wound surfaces reduces wound infection fromtrunk pathogens that cause grapevine decline. The aim of this studywas to determine the efficacy of pruning wound treatments containing Trichoderma as influenced by the time of pruning and time of application following pruning.
Cultivars Chenin Blanc and Cabernet Sauvignon were pruned early and late in thewinter season, respectively, corresponding to the break from thewinter dormancy period and the normal pruning time for these cultivars. After pruning, the woundswere treated immediately, 6, 24, 48 or 96h after pruning with either T. atroviride or T. harzianum. Colonisation of grapevine pruning wounds by the Trichoderma spp. was dependent on the physiological state of the vines as well as the weather conditions at pruning. In dormant vines, colonisation remained high from immediate application up to 48h after pruning. In vines at break of dormancy, colonisation was highest at 6 and 24h after application. Natural wound infection was higher in wounds pruned in late winter compared with that in early winter.
Conclusions: Applying the biocontrol agent 6h after pruning consistently resulted in a high incidence of Trichoderma spp. in both cultivars at either early or late pruning regardless of vine physiological state or the weather conditions.
Significance of Study: Pruning early in the season in combination with the application of Trichoderma spp. pruning-wound agents approximately 6h after pruning can significantly reduce wound infection by trunk pathogens.