Performance of the tobacco aphid Myzus persicae (Hemiptera : Aphididae) on Oriental and Virginia tobacco varieties

1 The life parameters of one red and one green clone of Myzus persicae reared on 11 Oriental tobacco type varieties (KP7, K63, KZ10/z, MA13/b, BX2/a, N34/4, KP14/a, Kolindros, S79, TA21 and BX81) and on five Virginia ones (VE9, VE3, SPG28-VE2, Kleio-KN1 and Niki-NK3) at 20degreesC and LD 16: 8 h were examined. 2 In general, the clones, performed better on Oriental than on Virginia type varieties. The varieties TA21 and Kolindros could be considered as the most resistant among the Oriental ones. Aphids on Virginia varieties showed longer developmental time (9.1-9.6days), a lower intrinsic rate of increase (0.2347-0.2647) and higher nymphal mortality (27.9-52.5%) than on Oriental varieties. The corresponding values in the latter were 7.3-9.0 days, 0.2784-0.3302 and 10.0-47.9%. 3 The leaves of Virginia type varieties (188-471 hairs/cm(2)) and one Oriental (K63) 273 hairs/cm(2) were more hairy than the other Oriental type varieties (61-150 hairs/cm(2)). The Virginia type varieties showed also a lower level of reducing sugars (3.5-7.2%) than the Oriental ones (7.0-9.8%). Trichome density and level of reducing sugars were significantly negatively correlated with developmental time and intrinsic rate of increase. 4 An interclonal variation in performance, possibly related to the colour of aphids, was observed. The red clone performed better than the green one. The same trend was observed when the results of the previous clones on the variety KP14/a were analysed with the data obtained on the same variety from two other clones (one red and one green)

Unraveling the tripartite interactions among the woolly poplar aphid, its host tree, and their environment: a lead to improve the management of a major tree plantation pest?

Article en open accessInternational audienceKey message For an optimal deployment of poplar resistance to the gall-inducing aphid Phloeomyzus passerinii, a laboratory susceptibility assay has been developed. The nature of aphid–tree interactions during compatible and incompatible situations has been studied in detail. This should help at identifying specific resistance markers and at testing effects of site conditions on tree–pest interactions. Context P. passerinii is a major pest of poplar plantations in Europe, and the plantation of resistant poplar genotypes is regarded as the best long-term management strategy for this pest. This requires a sound knowledge of the interactions among the pest, its host and their environment. Aims Here, we review the recent advances aiming at developing an optimal deployment of host resistance versus P. passerinii. Results Investigations on aphid-host interactions demonstrated that P. passerinii induces pseudogalls within the bark of susceptible hosts. This results in a reduction of starch bark content during aphid outbreaks, which could be involved in tree death. The constitutive level of starch in the bark could be related to the tolerance level of trees. A susceptibility test has been designed for poplar genotypes, discriminating three categories of susceptibility depending on tree’s ability to totally or partially inhibit pseudogall induction. The test still has several limitations however. It neither takes into account the large level of individual genetic diversity of the aphid in France, nor the environmental modulation of tree resistance and tolerance, while water deficit and fertilization could potentially affect these parameters. Conclusion The hypotheses drawn regarding the processes leading to tree death or resistance should help at identifying resistance markers, and at testing effects of site conditions on tree–pest interactions