Interactions between a specialist herbivore, Crocidosema plebejana, and its host plants Malva parviflora and cotton, Gossypium hirsutum: Larval performance

Abstract

AbstractPrevious studies have shown populations of tipworm, Crocidosema plebejana Zeller (Lepidoptera: Tortricidae), on Malva parviflora L. persist throughout the development of the plant while those on cotton are greatly reduced after plant flowering. We investigated larval performance of tipworm on plants of both species at various stages of development. Tipworm reared on M. parviflora developed faster, survived better and tended to be heavier than those reared on cotton. On M. parviflora all parts of the plant were eaten while on cotton large squares, flowers and small to medium bolls were never eaten. Cotton quality for tipworm development decreased markedly at flowering and remained low thereafter, as shown by low survival of neonate larvae and extended development time of late instar larvae. The poor performance of tipworm on flowering cotton is strongly correlated with major changes in plant chemistry at that stage of plant development.