Plant penetration by feeding aphids (Hemiptera, Aphidoidea): a review

Abstract

The factors responsible for determining the host-plants and feeding sites of aphids, and the various probing activities (the role of the labium, stylet insertion, surface saliva deposition, the behaviour of the aphid, virus transmission) are examined. There is a brief review of stylet structure and movement and the possible sensory nature of these organs, followed by a detailed review of the characteristics of aphid stylet paths in plant tissues. The penetration of epidermis and vascular tissues is treated separately while that within the intermediate tissues is covered in relation to leaves and stems, roots, trees, galls and excised tissue as well as in separate sections on Aphis fabaeScopoli and Myzus persicae (Sulzer). Stylet destinations and behaviour in the sieve tubes are discussed together with general features such as rate and depth of penetration, guidance to the feeding site, effects of tissue hardness and stylet withdrawal. The ingestion rate of plant sap is reviewed and its constitution and importance examined together with the significance of artificial diets. The salivary secretions including sheaths and tracks, their functions and their role in the transference of material between aphid and host are dealt with. The nature of the physical and internal damage resulting from aphid feeding is briefly covered, and also some plant-insect interrelations. The aphid species whose stylets have been examined in plant tissue are listed.

Categories of Resistance to Greenbug (Homoptera: Aphididae) Biotype I in <B> <I>Aegilops tauschii</I> </B> Germplasm

“…Aphids (Hemiptera: Aphididae) constitute the major group of phloem-feeding insects that utilize their slender stylets, which are modified mouthparts (Figure 1a and 1b), to tap into the sieve elements (Pollard, 1973;Blackman and Eastop, 2000). On their way to the vascular tissue, the aphid stylet follows a predominantly intercellular route (Tjallingii, 1990;Walling, 2000), thus minimizing physical damage to the plant tissue.…”

Intracellular ingestion and salivation by aphids may cause the acquisition and inoculation of non-persistently transmitted plant viruses.

“…Our results show that acquisition occurs primarily during the last sub-phase (II-3) of intracellular stylet punctures, whereas inoculation is achieved during the first sub-phase (II-1). An alternative mechanism to the ingestion-egestion hypothesis is proposed on the basis of our findings.The transmission of non-persistent plant viruses is unique to aphids (Homoptera : Aphididae) because they exhibit specific and characteristic activities during brief (a few seconds or minutes) and superficial probes, involved in host plant recognition (Pollard, 1973). Two different hypotheses have been proposed to explain the mechanism of transmission.…”

“…The transmission of non-persistent plant viruses is unique to aphids (Homoptera : Aphididae) because they exhibit specific and characteristic activities during brief (a few seconds or minutes) and superficial probes, involved in host plant recognition (Pollard, 1973). Two different hypotheses have been proposed to explain the mechanism of transmission.…”

Salivary gland structure of Ctenarytaina eucalypti (MASKELL, 1890) (Hemiptera) and phloem exudate in Eucalyptus globulus LABILLARDIÈRE, 1799 (Myrtaceae)

“…However, cursory details on stylet movement and feeding action in Psylla mali (SCHMIDBERGER, 1836) (Psyllidae) are available in WEBER (1929,1930), where WEBER explained that stylet action consists of a short protraction of one of the two mandibles followed by the other, each consequently sliding forward along the outside of the maxillae. However, this explanation was subsequently modified by POLLARD (1973). Extraction of phloem exudate was equally daunting especially because the well-known bleeding method (MERCHANT et al 2010), more suitable for Eucalyptus plants growing in natural conditions, could not be used.…”