Topic
Aphid
About: Aphid is a research topic. Over the lifetime, 11380 publications have been published within this topic receiving 229721 citations. The topic is also known as: Aphidoidea & plant lice.
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TL;DR: The progress made on identifying molecular factors and mechanisms that contribute to host defense, including plant resistance genes and signaling components, as well as aphid-derived effectors that elicit or attenuate host defenses are highlighted.
120 citations
TL;DR: The underlying mechanisms involved in the plant-mediated interaction between the non-pathogenic rhizobacterium Pseudomonas fluorescens and the parasitoid Diaeretiella rapae are evaluated by combining ecological, chemical and molecular approaches.
Abstract: Beneficial soil-borne microbes, such as mycorrhizal fungi or rhizobacteria, can affect the interactions of plants with aboveground insects at several trophic levels. While the mechanisms of interactions with herbivorous insects, that is, the second trophic level, are starting to be understood, it remains unknown how plants mediate the interactions between soil microbes and carnivorous insects, that is, the third trophic level. Using Arabidopsis thaliana Col-0 and the aphid Myzus persicae, we evaluate here the underlying mechanisms involved in the plant-mediated interaction between the non-pathogenic rhizobacterium Pseudomonas fluorescens and the parasitoid Diaeretiella rapae, by combining ecological, chemical and molecular approaches. Rhizobacterial colonization modifies the composition of the blend of herbivore-induced plant volatiles. The volatile blend from rhizobacteria-treated aphid-infested plants is less attractive to an aphid parasitoid, in terms of both olfactory preference behaviour and oviposition, than the volatile blend from aphid-infested plants without rhizobacteria. Importantly, the effect of rhizobacteria on both the emission of herbivore-induced volatiles and parasitoid response to aphid-infested plants is lost in an Arabidopsis mutant (aos/dde2-2) that is impaired in jasmonic acid production. By modifying the blend of herbivore-induced plant volatiles that depend on the jasmonic acid-signalling pathway, root-colonizing microbes interfere with the attraction of parasitoids of leaf herbivores.
120 citations
TL;DR: The monitored populations of the cabbage aphid, Brevicoryne brassicae, and the green peach aphid were monitored on broccoli interplanted with three leguminous cover crops and compared with broccoli without cover crop (clean cultivation), suggesting differential population growth rates and parasitism seen for M. persicae are a result of inhibition of D. rapae in the living mulches.
119 citations
TL;DR: The pest status of some aphids such as the pea aphid,Acyrthosiphon pisum (Harris), is considerably reduced by natural epizootics of fungal disease, however, disease may contribute little to practical control as it is mainly effective in high density populations when weather conditions are suitable.
Abstract: Diseases form an important component of the natural enemy complex of aphids. The most common and obvious of these diseases are entomophthoran fungi such asErynia neoaphidis Remaudiere & Herbert,Entomophthora planchoniana Cornu,Zoophthora radicans (Brefeld) Batko andConidiobolus obscurus (Hall & Dunn) Remaudiere & Keller. The pest status of some aphids such as the pea aphid,Acyrthosiphon pisum (Harris), is considerably reduced by natural epizootics of fungal disease. However, disease may contribute little to practical control as it is mainly effective in high density populations when weather conditions are suitable. Introduction of exotic diseases for classical biological control is only rarely possible since most diseases, like their aphid hosts, are distributed world-wide. One exception was the successful introduction into Australia of a strain ofZ. radicans for control of spotted alfalfa aphid,Therioaphis trifolii (Monell) f.maculata in 1979. Attempts to manipulate entomophthoran fungi have had limited success because of problems with mass production, the fragility of the conidia and the need for suitably moist conditions. Hyphomycete fungi such asVerticillium lecanii (Zimm.) Viegas,Metarhizium anisopliae (Metsch.) Sorokin,Beauveria bassiana (Bals.) Vuill. andPaecilomyces spp. are more suitable for development as mycoinsecticides as they are cheap to mass produce and form stable conidia. “Vertalec™”, a formulation ofV. lecanii, has been sold in small quantities commercially in Britain and parts of Europe for many years and used mainly in glasshouses. Recently promising results have been obtained with use ofM. anisopliae for control of lettuce root aphid,Pemphigus bursarius (L.) in the UK. Laboratory studies on selected isolates ofB. bassiana andPaecilomyces spp. show a promising level of activity. Problems may occur with these species as they can kill aphid predators such as coccinelids. In addition, more research is needed on developing improved formulations which enable control to be achieved under low humidity conditions.
118 citations
TL;DR: These experiments are the first to demonstrate a more indirect influence of parasites on insect polyphenism and the induction of wing development by parasitoids shows that host defences against parasites may also include an increased rate of dispersal away from infected habitats.
Abstract: In animals, inducible morphological defences against natural enemies mostly involve structures that are protective or make the individual invulnerable to future attack. In the majority of such examples, predators are the selecting agent while examples involving parasites are much less common. Aphids produce a winged dispersal morph under adverse conditions, such as crowding or poor plant quality. It has recently been demonstrated that pea aphids, Acyrthosiphon pisum, also produce winged offspring when exposed to predatory ladybirds, the first example of an enemy-induced morphological change facilitating dispersal. We examined the response of A. pisum to another important natural enemy, the parasitoid Aphidius ervi, in two sets of experiments. In the first set of experiments, two aphid clones both produced the highest proportion of winged offspring when exposed as colonies on plants to parasitoid females. In all cases, aphids exposed to male parasitoids produced a higher mean proportion of winged offspring than controls, but not significantly so. Aphid disturbance by parasitoids was greatest in female treatments, much less in male treatments and least in controls, tending to match the pattern of winged offspring production. In a second set of experiments, directly parasitised aphids produced no greater proportion of winged offspring than unparasitised controls, thus being parasitised itself is not used by aphids for induction of the winged morph. The induction of wing development by parasitoids shows that host defences against parasites may also include an increased rate of dispersal away from infected habitats. While previous work has shown that parasitism suppresses wing development in parasitised individuals, our experiments are the first to demonstrate a more indirect influence of parasites on insect polyphenism. Because predators and parasites differ fundamentally in a variety of attributes, our finding suggests that the wing production in response to natural enemies is of general occurrence in A. pisum and, perhaps, in other aphids.
118 citations