Life cycle of mealybugs Mealybugs appear frequently in ornamental and vegetable crops. Populations can reach a high density and so are a serious threat for growers. They cause damage by sucking plant sap. The overall effect is reduced photosynthesis and therefore decreasing yield. Where flowers and fruits are concerned, these often drop off. Mealy bugs also produce honeydew on which moulds grow. These sooty moulds result in considerable damage in crops. Mealy bugs get their name from the fact th