Since aphids are on the leaves, I shouldn't think you would need to soak the pot. The imidacloprid in Bayer Tree and Shrub is supposedly systemic, but I've never seen much effect when it is applied to roots. As a spray, it works nicely. Beware of ethyl alcohol. Some plants are sensitive. I once killed a large Paphiopedilum specimen while experimenting with ethyl alcohol as an insecticide. The alcohol got down in the leaf axils and destroyed the plant tissue. Isopropyl alcohol is less toxic to plants, and I use 70% isopropyl to control mealybugs on a variety of orchids and bulbs. Nick On Tue, Feb 18, 2014 at 12:56 PM, Rimmer <oldtulips@gmail.com> wrote: > on advice of someone directly in hopes of ending the aphids i have soaked > all my pots with a Merit based insecticide (Bayer Tree and Shrub) - 1 tsp > per 1 quart, is this too strong a solution? > > the aphids came with Oxalis callosa and O. obtuse - i tried Daconal which > scorched the Oxalis leaves under the T-5 lights so i used the insect soap > which does very little. > > Rimmer > > > pbs@lists.ibiblio.org > http://pacificbulbsociety.org/list.php > http://pacificbulbsociety.org/pbswiki/ > 70%