Articles
MEANS TO PRESERVE BENEFICIAL ARTHROPOD POPULATIONS IN FRENCH HAZELNUT ORCHARDS AS PART OF AN INTEGRATED PEST MANAGEMENT APPROACH
Article number
845_71
Pages
457 – 464
Language
English
Abstract
Two main pests that have to be chemically controlled in French hazelnut orchards are Curculio nucum and Phytoptus avellanae. Recent developments in regulations on pesticide use, which risk leading to a multiplication of sprays with less efficient pesticide treatments, have raised the prospect of outbreaks of secondary pests that were hitherto controlled naturally by beneficials.
Faced with this situation, it appeared important to identify populations of natural enemy species present in hazelnut orchards, to evaluate what non-target effects these forthcoming chemical substances could have on populations of beneficials and finally, to search for cultural practices that could be used to promote the return of predators into plots between two sprays.
The two first points were studied in 2006 and 2007 in five commercial orchards and in one wild orchard: the relative occurrences of the various categories of beneficials were quantified and the negative impacts of seven pesticides were compared.
Several were found to be more likely to induce outbreaks of minor pests, due to their toxicity for beneficials that kill aphids or mites in June.
The third objective was approached in 2007 on eight-year-old trees growing in a plot edged by a natural hedgerow.
Two levels of chemical control were compared in order to test whether it is possible to manage hazelnut orchards with minimal chemical control; the implication of environment in enhancing functional biodiversity was also observed.
It was concluded that, in a young orchard, restricting insecticide management to a single spray for nut weevil control does not induce an economically prejudicial damage rate, but what would be the outcome if a single spray control program were applied over consecutive years? The natural hedgerow, the grass cover, and the open space contribute to migrations of predators and prey; however, some vegetative species could provide shelter for the hazelnut weevil.
Faced with this situation, it appeared important to identify populations of natural enemy species present in hazelnut orchards, to evaluate what non-target effects these forthcoming chemical substances could have on populations of beneficials and finally, to search for cultural practices that could be used to promote the return of predators into plots between two sprays.
The two first points were studied in 2006 and 2007 in five commercial orchards and in one wild orchard: the relative occurrences of the various categories of beneficials were quantified and the negative impacts of seven pesticides were compared.
Several were found to be more likely to induce outbreaks of minor pests, due to their toxicity for beneficials that kill aphids or mites in June.
The third objective was approached in 2007 on eight-year-old trees growing in a plot edged by a natural hedgerow.
Two levels of chemical control were compared in order to test whether it is possible to manage hazelnut orchards with minimal chemical control; the implication of environment in enhancing functional biodiversity was also observed.
It was concluded that, in a young orchard, restricting insecticide management to a single spray for nut weevil control does not induce an economically prejudicial damage rate, but what would be the outcome if a single spray control program were applied over consecutive years? The natural hedgerow, the grass cover, and the open space contribute to migrations of predators and prey; however, some vegetative species could provide shelter for the hazelnut weevil.
Publication
Authors
M.M. Fernandez, L. Guitter, A. Bellahirech, A. Comte
Keywords
hazelnut Integrated Pest Management, non-target effects, biological control through conservation, Ecological Compensation Areas, functional biodiversity
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