Flat scarlet mite is a relatively sedentary pest which tends to live in groups.
- It overwinters as fertilised females on the bark of apple.
- They become active in early spring, from April onwards, and invade the foliage and flower/fruit clusters in May.
- The first eggs are laid on the wood late in April but subsequently eggs are laid along the midrib, beneath the leaf hairs. Eggs hatch from late June onwards.
- Mating takes place in August and September.
- The males die and fertilised females migrate to the bark where they overwinter.
- There is one generation per year.