Influence de la phenologie de la plante hote sur la reproduction de Ceuthorhynchus assimilis Payk
1991
Lerin, J.
Influence of host plant phenology on the reproduction of the rape weevil, Ceuthorhynchus assimilis Payk Results of a four years experiment on the reproduction of the seed pod weevil Ceuthorhynchus assimilis Payk. on winter rape (cultivar Jet Neuf) are presented. The mean fecundity of females has been assessed in cage experiments by the number of larvae reaching the last stage, as larval mortality in these conditions is negligible. Mean fecundity ranges from 45 to more than 150 eggs depending on the duration of flowering. The experimental results have been adjusted to a logistic curve explaining 78 % of the variability. The variability of pod infestation levels among years for the same number of females per plant is explained by the difference in flowering duration and plant vigour. The results are discussed along two main lines: the seed pod weevil adaptation to winter rape and the agronomical consequences of this variable fecundity on the control threshold of the pest.
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