The familliar convergent ladybug (Hippodamia convergens) is commonly found wherever aphids are abundant. Ladybugs are considered to be a generalist predator, meaning they will eat other soft bodied insects such as whiteflies or thrips. Ladybugs are field collected in the coastal montains and sold for home release or for use at commercial greenhouses. The ladybugs sold at Garden Retreat are the native Hippodamia convergens.
Ladybugs migrate in the same way that many birds do. At the end of the summer, the beetles will move into the mountains to feed on pollen and nectar, and store fat. When the weather turns cool, they will form large aggregations, up to one million beetles in a given area.
Now, when you are releasing ladybugs in your greenhouse or garden, since they have a tendency to disperse, you must follow the directions on the package carefully. The general idea is to release them at night in a cool nest-like environment. Mist the bugs and infested plants lightly with water and release the beetles onto the tree/shrub/greenhouse. Cover the plants with cheesecloth, remay, or a light blanket, and remove in the morning. The adults will consume some aphids, lay eggs on the undersides of leaves and may fly away. The nymphs will consume more aphids in their infancy than the adults, so be sure not to spray them.
You can encourage ladybugs to stay in your yard by growing dill, yarrow, carrots, and plants with bright flowers.