How to make your lady bugs stick around
Often people buy a bag of lady bugs, bring them home, and release them in the evening, only to get up the next morning and find nary a trace of the little fellows because they have all flown away. What can you do to make them want to stay? First, don’t use any lingering pesticides (such as malathion or kelthane) for 3 or 4 weeks before you release the lady bugs, or any other beneficials. Switch to insecticide soaps or plain water to knock those aphids off. Second, release your lady bugs at night, while it’s cool, immediately after giving your plants a generous sprinkle of water. (this is about the only time you should water in the evening!) The combination of moisture and the cool evening temperatures will convince your lady bugs to hang around, at least overnight. By morning they will be hungry, so they will look for breakfast before they leave. If there are enough aphids, thrips, or other appetizing ( to the lady bug) insects around, they just might stay. You can provide even more encouragement to settle down by spraying a commercial preparation of insect food, such as Wheast or Honeydew, on a few lower leaves of the aphid infested plants, or plant marigolds, yarrow, or angelica, which attract lady bugs.
Another trick is to release only a few lady bugs at a time, over a period of about a week, instead of emptying the entire bag all at once. Store the rest in the refrigerator (NOT in an airtight container!), but warn all the members of your family! And be sure to handle your lady bugs gently, or they will fly away.