When I had a lot of different plants at my old place I saw a lot of mealybugs as well as other pests. But I also had a lot of mealybug destroyers. Most people mistake them as mealybugs and kill them, but they will eat the mealybugs and the eggs. They also eat aphids and some soft scale. The adult mealybug destroyer will actually lay her eggs in the cottony egg-masses of the mealybugs so when they hatch they will have plenty to munch on. In these gardens I didn't spray because I was planting things for butterflies, ladybugs and LB larva, and any other good insect. But what I did do was put down the Bayer Tree and Shrub protect and feed granules when any infestations got ahead of the good bugs appetite. Since it is taken up into the plant through the roots it won't hurt the good insects since they don't munch on the plants, but it does kill any bad bugs that eat the plants (except spidermites). This isn't practical for large gardens though.
MEALYBUG DESTROYER LARVA
MEALYBUG DESTROYER ADULT
If you notice ant beds in the area, getting rid of them will help natural predators survive and keep the pests under control; this is true for aphids as well. Ants protect mealybugs and aphids so they can eat their honey dew (excretions). Parasitic wasp (mistaken for gnats often since they are so small) also help keep mealybugs under control.
If you need to use an insecticide I use the Bayer products with the Imidacloprid in it.
