I bought a Tropicana rose that I kept inside through winter. It had aphids that got bad and I used it as like a test subject to see what would work. Insecticidal soap hurt the rose worse than the aphids. Neem oil sprays and root soaks did nothing. So I finally decided to hit them with a real pesticide and got some Eight brand with lambda cyhalothrin. I sprayed the whole plant. Twice, over five days. And it seemed to do absolutely nothing to the green aphids.
I've searched the web and can find nothing about a pyrethroid failing to kill aphids, except a little I formation about some soybean aphids in the Midwest that are resistant. I'm wondering if the bottle of stuff is so old that the pyrethroid broke down completely. I got it off Amazon but there's no date on it.
Any thoughts or experience?
