VT Apple IPM: First big apple scab event expected

I may be a little late in getting this out, but everyone in the state should be prepared for the expected scab infection event that will be occurring Wednesday – Friday of this week. The NEWA model for some sites is still reading low for ascospore maturity- they are working on that in the back end. For most orchard in the Champlain Valley, we should have about 20% of ascospores mature- plenty to protect against. Be prepared with a preventative contact fungicide (mancozeb / captan, sulfur if organic) and consider adding a single-site product like Vangard or one of the DMI materials if you can’t get on before the rains start or you want some powdery mildew protection.

Insects are quiet so far, but I know some growers like to put a pink insecticide in as a matter of course. I’m not in that camp, and most sites are still a week out from pink anyway, but if you do use a prebloom insecticide, please stay away from neonicotinoids (IRAC group 4, e.g. Assail, Actara, Transform WG) that could express themselves in pollen and nectar and pose a unique danger to pollinators. Better yet, use white traps and only apply a prebloom insecticide against European apple safely and/or, in rare cases, tarnished plant bug, if populations are above threshold.

Make sure you order you codling moth traps and get them up in the orchard by bloom.

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