It is one of the smallest of all the ladybird beetles, yet Stethorus punctum , is often the most important beneficial insect to Pennsylvania apple growers. Growers have used integrated pest management practices to conserve this mite predator since it developed resistance by the 1970s to many of the organophosphate insecticides used in fruit production. By doing so, they have reduced miticide use in the state by half. They become blackish just before the larva emerges. Larvae are gray to blackish and have many long-branched hairs and black patches.
Pupae are uniformly black, small, and flattened.
The wing pads are prominent and the entire body is covered with yellow hairs. For a short period after it is formed, the pupa is orange. Stethorus produces three generations per year in south-central Pennsylvania. The average period from the time the egg is laid to the appearance of the adult is 23 days. The adults feed for an average of 25 days before beginning to lay eggs.