aphid control on rudbeckia?
Hello, I have lots of dark colored aphids on my rudbeckia. The last photo shows one white aphid (?) I've sprayed with a garlic, dish soap plus a few drops of olive oil spray, I've also tried spraying the hose at force to knock them off the plants. Not much luck. I've tried to squish the aphids with my fingers but can't get them all. Is it worth trying to spray with a neem oil solution? Or spraying again with water? I've been told that black eyed susans are fairly tough so maybe the effort is not worthwhile?
Here is our link on aphids and management. Usually predators and parasites (natural enemies keep them in check). No control is necessary. Simply monitor the health of the plants. You will have to decide later if you need to spray based on symptoms and pest levels. http://extension.umd.edu/hgic/aphids-flowers