Developing pruning wound protection strategies for managing Eutypa dieback

Abstract

Background and Aims: Eutypa dieback is an economically important disease of grapevines and a major threat to vineyard longevity throughout the world. Developing effective preventative strategies offers the best means of control. In this study, pruning wound protectants and various spray applications were evaluated for their ability to prevent infection by ascospores of Eutypa lata. Methods and Results: Fungicides and natural alternative treatments were applied by hand to grapevine pruning wounds in winter prior to inoculation with E. lata. In a series of greenhouse and field experiments, tebuconazole, pyraclostrobin, fluazinam, garlic extract and lactoferrin significantly reduced infection. A range of tractor-driven sprayers was used to apply tebuconazole to pruning wounds, and those which provided good coverage reduced infection by E. lata to a level similar to that when tebuconazole was applied with a paintbrush. Conclusion: Eutypa dieback can be controlled with several fungicides and natural treatments. Tractor-driven sprayers, which by design or modification can efficiently deliver maximum possible coverage at high output rates, can be used for application of pruning wound treatments. Significance of the Study: Results of this study contributed to registration of fungicides for use as pruning wound treatments to control E. lata in Australia. Demonstrating the ability of tractor-driven sprayers to apply treatments effectively has led to greater industry adoption of dormant treatments and may decrease the future impact of Eutypa dieback.