This article is part of our Organic Pest Control Series, which includes articles on attracting beneficial insects, controlling specific garden pests, and using organic pesticides.
Lady Beetles (Coleoptera)
Commonly called ladybugs, lady beetles are present in gardens throughout North America, in almost 200 slightly different variations. In addition to native ladybugs, the Asian lady beetles now inhabit millions of gardens, and move into houses and other structures for the winter. Most lady beetles are about one-quarter inch long, with red or orange-red backs decorated with black dots. Lady beetle larvae resemble tiny alligators, and are usually black or dark brown flecked with red or yellow.
When you see adult lady beetles on a plant, look about in the foliage for clusters of yellow to orange eggs, which are often located near an aphid colony. Dark little larvae hatch in about a week and begin searching for food. Young lady beetle larvae will consume several dozen aphids a day; in some species an almost-mature larvae may eat more than 100 aphids daily. After feeding for a month, the larvae pupate into adults. Multiple generations are common in warm climates.
What Do Ladybugs Eat?
Lady beetle larvae and adults eat aphids, small caterpillars, mites and random insect eggs. A few species specialize by feeding on scale insects, mealybugs, mites and even powdery mildew. Adult lady beetles also eat insect honeydew, flower nectar and pollen.
How to Attract Ladybugs
Tolerate light aphid outbreaks in spring, because they are an important food source for lady beetles, which emerge earlier in the season compared with hoverflies or lacewings. Do not use pesticides of any kind when lady beetles larvae are active. Grow a diversity of plants to provide pollen and nectar for lady beetles. Early-blooming mustard flowers attract adults in search of food.
Lady beetles are available for purchase and release from numerous companies that sell beneficial insects. Like other beneficial insects you might introduce into your garden, lady beetle releases are most likely to be successful if a good food source is ready and waiting. Lady beetles are able fliers, and will quickly leave an area where food is scarce.
More information on lady beetles is available from Colorado State University, Texas A & M University, and Oregon State University.