Biology and ecology of Pentalonia nigronervosa Coq. in Hawaii and aspects of its chemical control with imidacloprid

Abstract

Aphids are small, soft-bodied insects with sucking mouthparts that belong to the order Hemiptera, suborder Sternorrhyncha, family Aphididae. Their reproduction can be parthenogenetic or sexual, with cyclical parthenogenesis and associated host alteration being a feature of the family. Aphids often alternate between viviparity and oviparity, and may exhibit polyphenism, showing different sexual and morphological forms. Their development is hernimetabolous (Dixon 1998). There are approximately 4000 species described worldwide, most of which are present in temperate 4 regions (Dixon et al. 1987). Approximately 250 species are considered to be agricultural pests (Blackman and Eastop 1984). Problems associated with aphids include direct feeding damage and powdery mildew associated with honeydew excretion, but aphids are often only considered of economic importance as vectors of plant viruses (Agnos 1997). Monitoring for the presence of a pest can provide knowledge about its distribution, changes in its abundance, and provide information for the development of sustainable control strategies. The central component of monitoring is insect sampling (Binns et al. 2000; Dent 2000). Different types of sampling plans for aphids on several crops have been published, such as soybean (Hodgson et al. 2004; Onstad et al. 2005), tomatoes (Hummel et al. 2004), and Brussels sprouts (Wilson et al. 1983). At present, there are no sampling plans available for banana aphid, in Hawaii or elsewhere. Without such a plan, control efforts for P. nigronervosa cannot be undertaken in an economical and ecologically sound fashion, in keeping with the principles of integrated pest management (Dent 2000). Summary of chapters. Because the pathogen vectored by P. nigronervosa is affecting Hawaii's banana industry so adversely, I studied aspects of the biology, ecology, and control of this organism. Without understanding of the biology and ecology of P. nigronervosa, long term control of BBID will be difficult. Relevant local studies would be helpful to formulate effective control strategies for this aphid and its vectored pathogen. Control strategies for P. nigronervosa cannot be consistently applied without an effective aphid sampling plan, so I have chosen to formulate one. In addition, I have studied the efficacy of the newly approved chemical control for P. nigronervosa - imidacloprid - (commercial name - Provado 1.6F®).