Hello,
One of my hobbies is growing and breeding zinnias, which I have done for the last few years. I grow zinnias in the usual outdoor settings, but I also grow some "breeder" zinnias indoors during the late Fall, Winter, and early Spring. Zinnias are not houseplants, and growing them indoors presents a number of problems.
In the absence of normal outdoor enemies, Thrips can have a population explosion on indoor zinnias (and other indoor plants). Last Winter I fought an on-going battle with Thrips, which ended in a tie. I "controlled" a lot of Thrips and grew many breeder zinnias to seed production, but the Thrips developed an immunity to the Imidacloprid systemic insecticide I was using, and I had to move the third generation seedlings outside to spray them with Acephate, because the Thrips were killing them. I did spray some inside zinnia blooms with Acephate to kill the Thrips that infested the many crevices of the zinnia blooms, but commercial Acephate smells very bad and isn't suitable indoors for that reason. (The smell may actually be a contaminate, because a Google search turned up one foreign company that was offering to produce odorless Acephate, but as far as I know, no such product is available.)
So I am searching for a suitable systemic insecticide to control Thrips indoors on my zinnias. At this time last year I thought it was Imidacloprid, but it isn't. Incidentally, I believe the specific enemy was the Western Flower Thrips (Frankliniella occidentalis).
Thank you,
ZM
