Thrips are minute insects that can generally be found in new leaves that are beginning to unfold. Thrips feed on these leaves by sucking juices from the sub-epidermal cells. Such feeding results in abnormal leaf growth and a crinkled appearance of the leaves as they unfold and expand. Thrips are generally most abundant during the seedling phase of plant growth in hot, dry weather. Heavy infestations may stunt plant growth during the early portion of a growing season.