Active Woolly Apple Aphid Populations in Western New York

Dr. Monique Rivera, Cornell AgriTech

In conflict with all messaging provided on woolly apple aphids (WAA), we have surprisingly found active colonies in western New York. Typically, we expect to see WAA in late May and early June, not in the last week of March. We are assuming finding WAA activity this early is due to the mild winter, but we assume these populations will pick up very quickly as the season progresses. We were finding these colonies feeding in previous woolly apple aphid tree wounds.

What to look for: Interestingly, we tended to find the colonies nearby old and dead woollies from the previous year. However, this was in a research orchard and unless your infestation was very substantial around harvest last year, I wouldn’t expect you to see dead older adults. In your own orchard, what you are looking for is young WAA (Photo 1). They are hard to see and very good at hiding. They are purple-ish brown in color and generally tuck themselves in crevices. We tended to find them with white residue from previous infestations which could be a useful looking cue when searching an orchard. You will absolutely need patience and a hand lens. If you have access to a microscope, collecting branch samples from the field and using the microscope makes looking a lot easier. If you are looking for a tool that is cheap and works like a microscope, look up “usb microscope” and there are great options for $40 and under.

Photo 1: Young, active, Woolly Apple Aphids collected from WNY March 26, 2024.

So, what does this mean for WAA management?

If you can time it correctly, putting an oils at 2-3% on is definitely recommended. There has not been work on what insecticides will work the best at early spring timing. If you do plan to put a WAA insecticide out pre-bloom, be sure to check the label and consider potential effects it may have on pollinators and beneficials.  Note that Movento cannot be applied before petal fall. Be ready in blocks that had high WAA populations last year to get an application on as soon as you can at petal fall.

Advice for applications: Apply during cooler temperatures because this slows down any movement the WAA will have. Because we do not have leaves, applying at 50 gallons per acre is sufficient for coverage but still continue to drive slow, 2.5 mph or less.

 

 

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