Resumen de Optimisation of time of application of Trichoderma biocontrol agents for protection of grapevine pruning wounds
C. Mutawila, F. Halleen, Lizel Mostert
Background and Aims The application of Trichoderma species on grapevine pruning wound surfaces reduces wound infection from trunk pathogens that cause grapevine decline. The aim of this study was to determine the efficacy of pruning wound treatments containing Trichoderma as influenced by the time of pruning and time of application following pruning.
Methods and Results Cultivars Chenin Blanc and Cabernet Sauvignon were pruned early and late in the winter season, respectively, corresponding to the break from the winter dormancy period and the normal pruning time for these cultivars. After pruning, the wounds were treated immediately, 6, 24, 48 or 96 h 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 48 h after pruning. In vines at break of dormancy, colonisation was highest at 6 and 24 h after application. Natural wound infection was higher in wounds pruned in late winter compared with that in early winter.
Conclusions Applying the biocontrol agent 6 h 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 6 h after pruning can significantly reduce wound infection by trunk pathogens.
