Spraying for peach leaf curl. I’m planning to spray my multi fruit nectarine tree with Lime sulphur. The instructions say to apply before buds break but I’m wondering if the buds I see have come out early with the warm weather.
Is this what is considered bud break or do I still have time to spray my tree?
I’ve wondered about this often! My unexpert opinion is that they are close but not quite at bud break.
This question has been forwarded to the Vancouver Island Master Gardeners. They should have a response for us by next Thursday (they receive questions once per week, on Tuesdays). With the cold weather coming, it’s unlikely the buds will open any further right now.
Thank you to members of the Vancouver Island Master Gardeners through the Garden Advice Line at Milner Gardens and Woodland for this response:
Peach Leaf Curl (Taphrina deformans) is caused by a fungus. Spores overwinter in crevices of tree bark and around buds and develop on infected leaves. Entomologist Linda Gilkeson says, “Lime-Sulphur sprays reduce the levels of infections [from leaf curl] by preventing spores from germinating. Spray in the fall after most (about 90%) of the leaves have fallen and again in the very early spring before buds swell.”
Since it looks like the buds have already begun to swell (likely due to a long warmish spell earlier this winter) it probably won’t be effective to spray now, although it won’t damage the tree to do so.
The best defense against leaf curl is to keep the tree out of the rain, especially during the February to March infection period. A tree can be espaliered against a garage wall, for example, so it is sheltered by the roof overhang.
The tree in the photo may not be situated next to a wall. However, a makeshift canopy can be used instead, perhaps made with stakes and a tarp or heavy duty plastic.
The spores need the right conditions to germinate. We have had a dry spell so maybe that will prevent them from germinating this year. However, they can go dormant and germinate next year.