Partenaires et organisations internationales
(Anglais)
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A, B, CZ, DK, FIN, F, D, H, IRL, I, NL, N, PL, P, RO, E, S, CH, GB
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Résumé des résultats (Abstract)
(Anglais)
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Two insect pests of rape, the cabbage root fly (Delia radicum) and the diamond-back moth, (Plutella xylostella) clearly preferred normally or double fertilized plants over plants receiving no sulphur nutrition at all. The females of both insects laid more eggs on the sulphur fertilized plants and the progeny emerging from the eggs (larvae, caterpillars) fed more and developed better and faster than on the non-fertilized plants. Sulphur fertilization enhanced in the leaves the content of sulphur containing secondary metabolites such as the glucosinolates. Specific compounds increased the attractivity of the plants and stimulated egg laying by each of the two pest insects.Thus the question arises if sulphur fertilization of rape is leading to increased numbers of pests attacking the crop and to a multiplication of the pest populations in the fields. In order to test this question we compared normal with double normal fertilized plants. Within the levels of sulphur fertilization tested the pests showed only a minor, mostly not significant, preference for the plants receiving the double amount of sulphur. Based on these results we concluded that the plant sulphur supply, in the range of the field concentration, could be varied by a factor of two without dramatically effecting the pest insect populations. Thus sulphur fertilization can be optimized to allow good harvests without significantly increasing pest problems.
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