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.

Antagonistic effects of soybean viruses on soybean aphid performance.

Abstract: Although there is long-standing recognition that pest complexes require different management approaches than individual pests, relatively little research has explored how pests interact. In particular, little is known of how herbivorous insects and plant pathogens interact when sharing the same host plant. The soybean aphid, Aphis glycines Mastumura, a recently introduced pest of soybean in the upper midwestern United States, and a complex of plant viruses vectored to soybean by insects have become a major concern for growers in the region. Given the abundance of soybean aphid and the increase in virus incidence in recent years, soybean aphids often use soybean infected by plant viral pathogens. We tested the hypothesis that soybean aphid performance is affected by virus infection of soybean plants. We conducted a series of field and laboratory experiments that examined how infection of soybeans with the common plant viruses, alfalfa mosaic, soybean mosaic, and bean pod mottle viruses, influenced soybean aphid performance. Soybean plants (in the field and laboratory) were hand inoculated with individual viruses, and aphids were allowed to colonize plants naturally in field experiments or added to the plants in clip-cages or within mesh bags in laboratory assays. In the field, aphid density on uninfected control soybean plants was nearly double that on infected plants. In laboratory assays, aphid population growth rates were on average 20% lower for aphids on virus infected compared with uninfected plants. Life table analyses showed that increased mortality on virus-infected plants likely explain differences in aphid population growth. Although there was some heterogeneity in the significance of treatment effects among different experiments, when independent experiments are taken together, there is on average an overall negative effect of these viruses on soybean aphids.

The chemical ecology of aphid host alternation: How do return migrants find the primary host plant?

Abstract: The life cycle of some aphid species involves seasonal switches between unrelated summer (secondary) and winter (primary) host plants. Many of these “host-alternating” species, belonging to the sub-family Aphidinae, produce two return migrant forms on secondary host plants in autumn. Winged females (gynoparae) are produced first; these locate the primary host and deposit their sexual female offspring (oviparae). Later, males are produced on the secondary host and these locate the primary host independently before mating with the oviparae. The mechanisms of primary-host location by gynoparae and males are reviewed in this paper. Studies with several aphid species indicate that both forms are able to respond to volatile cues released by their specific primary host plant. Plant odours may also enhance or modify the responses of return migrants to the sex pheromone released by mature oviparae. Aphids are also able to sample non-volatile plant chemicals after landing, but there have been very few detailed investigations of the behaviour of return migrants at the primary-host-plant surface. Recent experiments with gynoparae of the black bean aphid, Aphis fabae Scopoli, show that these insects detect primary-host-specific cues during stylet penetration of peripheral plant tissues, and these stimuli promote settling and reproduction. Similar behavioural studies with males are required to shed light on the processes of speciation and reproductive isolation in host-alternating aphids.

Change in response of Rhopalosiphum padi spring migrants to the repellent winter host component methyl salicylate

Abstract: Olfactometry showed that the response of spring migrants of the bird cherry-oat aphid, Rhopalosiphum padi (L.) (Homoptera: Aphididae), to the repellent winter host volatile methyl salicylate changes with age of the adult aphid. Between three and four days after becoming adult, and having left the winter host Prunus padus L., aphids lost their negative response to the chemical. The change in response was not associated with contact with a summer host, oats. In a settling choice bioassay, migrants avoided oats which had been exposed to volatile methyl salicylate. Aphids with removed antennal tips did not avoid the exposed plant, indicating that plant choice was influenced by cues from the plant surface. The results are discussed in relation to the use of methyl salicylate in integrated control.