Asked November 10, 2023, 10:12 AM EST
Normally, I can expect one invasion of caterpillars (tobacco budworms and....?) towards the end of July/August, on my petunias, snapdragons, and lantana in planter boxes on my 3rd floor balconies. While I experience some destruction, I can keep up with them enough to keep them blooming (hand picking them and throwing them overboard. This year, I had a second invasion in Sept. that decimated my plants. In addition, I had whiteflies and aphids, something I've never had to deal with. I tried using a solution of alcohol and water for the latter two, as well as insecticidal soap. The blooms didn't fair well with either, and neither got rid of the insects.
My 1st question is this: Should I dispose of all the potting soil to reduce the number of insects that might have laid eggs, or be cocooning in the soil? I know that the aphids have several strange life cycles--winged, wingless, etc. So I can't entirely rid myself of them. I don't know what to say about the caterpillars (it might have been two different species) to reduce my stress about losing all my blooms when normally the flowers are at peak. It's very time consuming to search for them as they cause lots of damage when they're still very small and camouflaged.
2nd question: I saw very few ladybugs helping out. Not nearly enough. Any suggestions for the aphids and whiteflies?
Many thanks!!
Judy
Hennepin County Minnesota