Grape growers know that pruning provides better quantity and quality of grapes come harvest time. But remember, pruning wounds are also a port of entry for many fungal pathogens.
Fungi that infect pruning wounds can eventually cause diseases which reduce the vine’s productivity and fruit quality and shorten the life of the vine. These diseases include bot canker, Phomopsis and Eutypa dieback.
“Eutypa is a pretty serious disease, which can actually kill the whole arm of the vine,” says Emily Smith, Technical Service Manager for UPL. “Eventually the shoots will be stunted and there will be no fruit. This will absolutely affect the grower’s pocketbook at the end of the season.”
A first step toward preventing pruning infections is to prune in the springtime when the weather is relatively warm and dry, says Smith. Pruning wounds will heal faster during warm weather than cold weather, whereas rain disperses the fungal spores, making conditions worse.
Applying a pruning wound protectant is another way to minimize damage to your vineyard. Good coverage is important for optimizing the performance of protectants.
Wound sealants with boric acid and essential oils can help protect pruning wounds. Applying fungicides to the pruning wounds while the vine is healing can also limit infection.
“UPL has a product called TOPSIN® M fungicide that is quite effective on Eutypa and bot canker,” says Smith. “It’s often used in conjunction with Rally fungicide. Together, these two products provide excellent control of Eutypa, bot canker and Phomopsis. They also can take care of any type of powdery mildew that’s out there at the time.”
TOPSIN® M WSB fungicide (FRAC M1) is a systemic fungicide that moves from top to bottom, and upward and outward within the leaves and stem. It is recommended that TOPSIN be rotated with fungicides in different FRAC groups. TOPSIN M WSB for Eutypa dieback is approved for use under specific state local-need labels.
“We have a 2ee registration for Topsin that covers pruning wound applications for western grapevines,” says Smith. “It is a very, very effective product.”
To hear more from Emily on pruning wounds, click here.
For more on TOPSIN or other UPL products, contact your local UPL representative.
