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.

Effect of Weedy Backgrounds on Colonization of Collards by Green Peach Aphid, Myzus persicae , and Its Major Predators

Abstract: Insect colonization of collards in contiguous weedy and weed-free plots was monitored in 1978 and 1979. Green peach aphids, Myzus persicae (Sulzer) preferentially invaded weed-free collards and developed higher densities thereon. Numbers of Chrysopa oculata (Say), Coccinellidae, and Syrphidae were higher in plots in which weeds were uncut, despite lower aphid densities. When weeds were trimmed to 10 cm maximum height, predators became more numerous on weedless collards. Predator response were generally inefficient, especially when overall aphid densities were low.

The aphids' peripheral perception of plant volatiles

Abstract: In aphids the olfactory receptor neurones are housed in placoid sensilla on the antennae, the so-called distal and proximal primary rhinaria on segments six and five, respectively, and, in winged aphids, the secondary rhinaria on segments three and four (Shambaugh et al, 1978; Bromley et al., 1979). The overall responses of these receptors to plant odours can be studied by the electroantennogram (EAG) technique. In this way, it can be shown which plant volatiles are detected and, thus, are likely to play a role in the discrimination between the odour blends of host and non-host plant species during orientation and landing. EAGs in response to plant volatiles have been recorded in a number of aphid species, i.e., the English grain aphid Sitobion avenae (F.) and the rose-grain aphid Metopolophium dirhodum (Walk.) (Yan & Visser, 1982; Visser & Yan, 1995), the black bean aphid Aphis fabae Scop. (Hardie et al., 1995), and the vetch aphid Megoura viciae Buckton (Visser & Piron, 1994, 1995).

Behavioural and physiological adaptations of pea aphids (homoptera: aphididae) to high ground temperatures and predator disturbance

Abstract: Pea aphids can avoid ladybug predators by dropping from the food plant when disturbed. Once off the plant the aphid must find another food plant. If temperatures on the ground are high, the aphid may die before finding a new food plant. In Kamloops, B.C., summers are hot and dry, compared with Vancouver where the climate is warm and moist. Pea aphids from Kamloops generally exhibit back-up behaviour and rarely drop from the plant when approached by a ladybug. By contrast, Vancouver pea aphids readily drop from the plant when disturbed by a predator. Adult aphids from Kamloops are more tolerant of heat under moist conditions at 37.5 °C than Vancouver adults but under dry conditions and at 42 °C, both groups have similar survival times. First instars of both aphid biotypes die sooner at high temperatures than adults. Mortality of aphids on the ground is sufficiently high to select against dropping behaviour as a first line defense against predators in areas with hot, dry climates.

A screen of worldwide wheat cultivars for hydroxamic acid levels and aphid antixenosis

Abstract: Summary In a screen of seedlings of a worldwide range of 47 cultivars of Triticum (mainly T. aestivum) the concentration of the hydroxamic acid DIMBOA ranged between 1 and 8 mmol/kg fresh wt. In a bioassay in which alatae of the aphid Sitobion avenae were released among replicated test seedlings, there were highly significant correlations between aphid ‘preference’ and DIMBOA levels in the seedlings. The value of these results in work leading to the production of aphid-resistant cultivars is discussed.