Just wrote a long reply and then lost it. Here we go again...
Deb. I never remember aphids in my greenhouse until last year some showed up on my California Wonder Bells. I sprayed them with soapy water, and that kept them in check, but did not eliminate them totally.
One thing I did differently was to grow all winter in this new greenhouse. The temperature never fell below 40 all winter. The last few years, I left my old greenhouse empty for the winter so I could store and cut firewood during the winter. I believe the freezing temps at night probably killed any bugs that thought about overwintering in my greenhouse. I noticed them first this winter on my spinach and lettuce. I figured they were "hold outs" in the greenhouse from the summer peppers, but that is all guesswork on my part. May or may not be true. Next, they were on my potatoes, and now they are on my pepper and tomatoes seedlings. All brown aphids. They don't seem to care for my brassicas, melons, or any other vegetables at this time. I spray with soapy water every day. I can see the shriveled, dead aphids the next day where I sprayed, but more keep coming...not an overwhelming amount, but like I said, I spray just about every day. I am terrified of them getting out of control.
From your description, sounds like your case is worse than mine, but I get panicky when I think of what could happen in my greenhouse if I don't get/keep them in check. (I don't ever remember seeing aphids on my outdoor plants/fruit trees/berry bushes, but my fruit trees are only 3-4 years old and not big fruit bearers yet. Some have yet to bear fruit at all.) I am planting a ton of marigolds, geraniums and yellow yarrow in my greenhouse this summer. Aphids hate marigolds and geranium scent, and all three attract beneficial insects that like to eat aphids, especially the yellow yarrow that attracts lacewings. Aphids are very high on the diet for lacewings.
You could try planting (especially) yellow yarrow in the vicinity of your fruit trees. They are easy to grow from seed, but they take a while to bloom.
Problem with using flowers is the aphids usually show up before the flowers bloom and give off their scents and/or attract aphid eating bugs. I do plan to keep these three plants growing all year in my greenhouse if possible, and if they work as I have read.
Another vey organic, very effective treatment against just about all pests that attach fruit and fruit trees is Kaolin Clay. (
https://www.phillyorchards.org...) There are many articles and you tubes available on Kaolin Caly. You thoroughly mix it with water and spray on your trees, leaves and fruits. It forms a white coating of clay that bugs hate/messes with them. It is perfectly safe for the plants, humans and animals. It needs to be sprayed with a diaphragm sprayer or a sprayer that mixes continuously during use. It will clog the normal piston garden sprayer unless you keep shaking it alot.
Here in this picture is a tree that has been sprayed (from the internet). Not pretty, but there are long-time fruit growers who swear by it.
Let's keep sharing ideas/methods. I'm sure others have had/are having this problem as well.
