If your insects aren't too bad you could use orthenex 3in1. Kills common stuff like mites, mealies and aphids and has a fungicide. I have used it once in a while when the insects weren't too bad. If you have a really bad infestation you might want to consider Orthene or concentrated Merit (Imidacloprid) paired with an exterior fungicide if you are really worried about fungal problems being persistent.
Heres orthenex
Orthenex Insect & Disease Concentrate Pint at Merrifield Garden Center
and here and here is a link to a page with Orthene and Merit in concentrated forms, there are also a few other insecticides and fungicides mentioned if you want to explore a little.
Insecticides
Hope this is helpful
Have Fun!