Summary of Progress:

This is the second year of the project focused on evaluating alternative nursery practices to reduce graft union failure in grapevine propagation.  This study examined how nursery practices influence graft union success and disease management in grapevine propagation.  Results showed that fresh cut length did not significantly impact grafting success across three nurseries.  However, certain biological and chemical treatments, including Pseudomonas chlororaphis, Bacillus velezensis (GCM), Vintec, Serifel, and Topsin M, enhanced callus formation at the graft union and rootstock ends under varying nursery conditions.  Greenhouse trials demonstrated that Bacillus velezensis (GCM) and Topsin M effectively reduced lesion size and necrosis caused by Neofusicoccum parvum, while Vintec lowered pathogen recovery.  For Eutypa lata, treatments had minimal impact on lesion size, though Bacillus velezensis (GCM) and Topsin M reduced necrotic tissue, and pathogen recovery was lowered with Vintec, Bacillus velezensis (GCM), Topsin M, and Luna Sensation.  Treatment effectiveness varied between nurseries, and responses to Eutypa lata were inconsistent.  Additionally, Botrytis cinerea contamination during cold storage may contribute to graft union failure, highlighting the need for further study.

Future research will focus on testing additional biological and chemical treatments for GTD pathogen control, investigating Botrytis cinerea contamination, and refining nursery handling practices to improve hygiene and disease prevention.  Continued funding is essential to expand these trials, validate findings in real-world nursery settings, and provide growers with reliable disease management strategies.  Our work aims to identify factors influencing graft success, including biological and chemical treatments on propagation material, with the goal of improving overall plant quality and disease resistance.