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The essential oils extracted from six plants from Kabylia (Algeria), namely Eucalyptus globulus, Eucalyptus radiata, Myrtus communis, Salvia officinalis, Laurus nobilis and Pistacia lentiscus, were analysed by gas chromatography (GC/MS). Their biological activity was assessed on a pest destructive of stored products, Callosobruchus maculatus on cowpea (Vigna unguicultata). The results showed that these oils have two monoterpene compounds in common: alpha-pinene and beta-pinene in different proportions. The bio-tests were conducted through contact, fumigation and repellency, under laboratory conditions. All the oils tested proved to be active, and the most significant action was the inhibition of oviposition during the tests through contact at a dose of 12 mu l/50 g of bean seed. The essential oil of E. globulus caused 50% mortality in adult C. maculatus at 24 hours at a dose of 4 mu l/l of air in fumigation tests. In addition, the essential oils tested were highly repellent towards adult C. maculatus at a dose of 16 mu l.

International audience

International audience

International audience

International audience

Conventional agriculture is based on a high level of chemical inputs such as pesticides and fertilisers, leading to serious environmental impacts, health risks and loss of biodiversity in agrosystems. The reduction of pesticide use is a priority for intensively sprayed agricultural systems such as orchards. The preservation and promotion of biodiversity within orchards and their boundaries is therefore an issue to explore. Indeed, orchard systems contain high plant diversity and perennial multi-strata designs that provide wealthy resources and habitats to living communities such as beneficial organisms. Orchards thus offer favourable areas to maintain food-webs within the agrosystem, provided that favourable situations are not altered by cultural practices such as applying an excess of pesticides. Here, we analysed literature on the effects of the manipulation of plant diversity and habitats on the control of pests by arthropod and bird communities in apple, pear and peach orchards. Many investigations focus on the role of plant management to enhance biodiversity in orchards but only 22 research reports presenting 30 case studies were dedicated to the study of the ecosystem service provided by plant diversity for orchard pest control. The underlying mechanisms were seldom demonstrated, and the tested grass covers and tree assemblages aimed at favouring either the beneficial complex or only some beneficial species to control one or a few pests. The effect of plant management on pest control was mostly positive (16 cases) or null (9), but also negative in some cases (5). This finding reveals the difficulties of identifying selected plants or plant assemblages for the control of key pests. We conclude that further research is needed to identify the processes involved on different scales for biological control. Orchard systems should be re-designed to optimise ecosystem services provided by biodiversity.

National audience; Farming intensification in recent decades has led to an alarming level of degradation and loss of wildlife and its hedgerow habitat. The relationship between biodiversity and ecosystem functioning has emerged as a central issue in ecological sciences, but the situation regarding hedgerow function as a potential source of biological control agents against agricultural pests remains poorly understood. We evaluated possible effects of the arthropod community in a neighbouring hedge on the distribution of the pest psylla Cacopsylla pyri L. (Hemiptera: Psyllidae) in a pear orchard Pyrus communis L. over three consecutive years (1999-2001). We measured the diversity of the arthropod community in the hedge and in the orchard at increasing distances from the hedge using Shannon index of diversity, and the Hellinger distance and Mahalanobis index to highlight dissimilarities between population distributions. Our results showed a convergence between predator populations in the orchard and the hedgerow during Psylla proliferation. There was a decreasing diversity gradient as distance from the hedge increased. Beneficial arthropod exchanges occurring between the mixed hedgerow and the pear orchard during the pest proliferation period suggest that field border management can be used in an integrated pest management strategy aimed at reducing insecticide use.