The work described was done with larvae and adults of virginoparae of the green peach aphid, Myzus persicae Sulz. and the cabbage aphid, Brvicoryne brassicae L. on Brussels sprouts, Brassica oleracea L. var. bullata gemmifera. The responses of the aphids to three leaf ages of the plants subjected to differing levels of intermittent water strain are described and compared for each aphid species in terms of 1) the selection of the leaves and plants by settling alatae, 2) the preferences of the apterae for leaves of different age and water status, and 3) the fecundity, reproductive rate, rate of development, longevity, reproductive life, post-reproductive life and proportion of alatae in the progeny of apterae on leaves of different age and water status. The suitability of the different leaves and plants as hosts for the two aphid species is assessed. The responses of the aphids to three leaf ages of plants subjected to no water strain or to a single period of increasing water strain are described and compared for each aphid species in terms of the survival, reproductive rate and restlessness of apterae. A relationship is demonstrated between the water content of the growing medium of the plants and the larvi position of aphids feeding on the plants. The methods of penetration and the destinations of the stylets and salivary sheaths of the two aphid species in the leaves of the plants are described. Preliminary experiments are described in which aphids were fed on artificial liquid diets under controlled pressures. The possible causes of the responses of the aphids to leaves of different age on plants of different water status are examined particularly by comparing the two aphid species. The possible economic importance of the responses of aphids to water strain in plants is discussed with reference to aphid control.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:622980 |
| Date | January 1967 |
| Creators | Wearing, Christopher Howard |
| Publisher | Imperial College London |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/10044/1/17614 |
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