Tool hygiene and supervision important through pruning
KVH this week visited a Gold3 orchard with multiple plants showing Psa infection symptoms both above and below autumn applied girdles.
Vines had been girdled for the first time ever in January, with the girdle re-opened in February. Copper was applied to girdles in January; in February no copper was applied, though girdles were taped to assist healing.
The pattern of infection within blocks suggested poor girdling technique and lack of tool hygiene are likely to have been factors leading to vine infection - grower survey found that for some rows, 50% of plants were affected.
This result is disappointing and a reminder that wounds are potential infection points for Psa. Research (available on the KVH website) has shown unprotected girdles can be infected for at least 15 days after the girdle is applied, and infection generally follows specific high-risk weather patterns.
Similar risk should also be considered when planning pruning rounds. As pruning commences, make sure winter rate copper is applied ahead of and after pruning. Insist on good tool hygiene and team supervision to make sure your rules are being followed.
Check the Psa risk model to help with spray and pruning planning.