VT Apple IPM: Bloom

With orchards in the Champlain and Connecticut valleys heading into bloom now and even inland/upland orchards expected to show some blossoms later this week, it’s ‘go-time’ for setting up the 2023 Vermont apple crop. We are thankfully looking at an incredible week- sunny and 60s or 70s every day as far as the outlook goes, and cool but not cold nights expected, no rain. If ever there were a Goldilocks bloom season, this is it.

It goes without saying but I will say it that we don’t need to be spraying any insecticides heading into bloom. If you are at early pink stage at the latest and if you have a documented population of tarnished plant bug or European apple sawfly and if your markets can’t absorb a little cosmetically-damaged fruit (i.e., if you sell to wholesale markets) and if you have mowed all flowering weeds like dandelions that would be bringing pollinators into your orchard now , then a low-residual non-systemic (i.e., non-neonicotinoid) insecticide may be applied to manage those pests- but that’s a pretty small Venn diagram I described. Given the dry weather, I don’t see any need for a fungicide, assuming that you were covered during last week’s long apple scab infection event. The cool weather looks to be keeping fire blight bacteria at a low epiphytic infection potential so we can’t expect that disease to be an issues- but pay attention to NEWA this week as the bacteria that causes the disease can rapidly multiply if the weather warms and open blossoms would need treatment with streptomycin or a biological material (Blossom Protect, etc., only recommended for organic orchards as the efficacy is much lower than strep).

This is a good week to get irrigation going. This would also allow for fertigation of important nutrients, especially nitrogen and boron that are in high demand with the flush of new growth we see at this time of year. Finally, I hope to see some of you at the Apple Pollinator Workshop at 4:30-6:30 on Wednesday, May 10 at the UVM Horticulture Research and Education Center, 65 Green Mountain Drive, South Burlington VT.

Apple meeting agenda for 5.10.2023 twilight meeting.pdf