Papers by Jean-françois Toubon
Naturwissenschaften, 2007
The behavioral and electroantennographic responses of Cydia pomonella (L.) to the ripe pear volat... more The behavioral and electroantennographic responses of Cydia pomonella (L.) to the ripe pear volatile ethyl (2E,4Z)-2,4-decadienoate (Et-E,Z-DD), were compared in insecticide-susceptible and -resistant populations originating from southern France. A dose–response relationship to this kairomonal attractant was established for antennal activity and did not reveal differences between susceptible and resistant strains. Conversely, males of the laboratory strains expressing metabolic [cytochrome P450-dependent
Environmental Toxicology and Chemistry, 2005
The impact of conventional, organic, and integrated pest management (IPM) strategies of apple orc... more The impact of conventional, organic, and integrated pest management (IPM) strategies of apple orchards on the reproduction of the great tit Parus major was investigated during a three-year period in southeastern France. The colonization process, egg-laying dates, clutch sizes, and fledging success were similar among pairs of P. major nesting in orchards conducted under the three studied management strategies. However, the mean number of young produced per ha (orchard productivity) was significantly higher in organic orchards than in both conventional and IPM orchards. Such divergences between both fledging success and orchard productivity primarily resulted from higher densities of P. major nesting pairs, but also from lower rates of nest abandonment during incubation in organic orchards. We suggest that intensive pesticide use under both IPM and conventional managements may have resulted in a substantial reduction in insect prey availability that enhanced intraspecific competition, which then led to failure in reproduction in pairs with low competitive ability. Our results highlight the relevance of P. major in assessing the environmental impact of apple orchard management strategies.
PLoS ONE, 2012
Resistance to insecticides is one interesting example of a rapid current evolutionary change. DNA... more Resistance to insecticides is one interesting example of a rapid current evolutionary change. DNA variability in the voltagegated sodium channel gene (trans-membrane segments 5 and 6 in domain II) was investigated in order to estimate resistance evolution to pyrethroid in codling moth populations at the World level. DNA variation among 38 sequences revealed a unique kdr mutation (L1014F) involved in pyrethroid resistance in this gene region, which likely resulted from several convergent substitutions. The analysis of codling moth samples from 52 apple orchards in 19 countries using a simple PCR-RFLP confirmed that this kdr mutation is almost worldwide distributed. The proportions of kdr mutation were negatively correlated with the annual temperatures in the sampled regions. Homozygous kdr genotypes in the French apple orchards showed lower P450 cytochrome oxidase activities than other genotypes. The most plausible interpretation of the geographic distribution of kdr in codling moth populations is that it has both multiple independent origins and a spreading limited by low temperature and negative interaction with the presence of alternative resistance mechanisms to pyrethroid in the populations.
Landscape Ecology, 2009
Managing the spatial distribution of crop and non-crop habitats over landscapes could be used as ... more Managing the spatial distribution of crop and non-crop habitats over landscapes could be used as a means to reduce insect pest densities. In this study, we investigated whether or not landscape characteristics affected the number of codling moths in commercial orchards. To do this, we collected overwintering larvae in 2006 and 2007 in 76 orchards over a 70 km² area in
Heredity, 1998
Genetic variability of 22 populations of Helicoverpa armigera (Hübner) (Lepidoptera, Noctuidae) w... more Genetic variability of 22 populations of Helicoverpa armigera (Hübner) (Lepidoptera, Noctuidae) was studied by comparison of allozyme frequencies at 15 loci. Seven loci were polymorphic at the 99% level. Populations originated from the south of France, Portugal, Morocco, Tunisia, Burkina Faso and Ivory Coast. Few significant deviations from Hardy-Weinberg equilibrium occurred, except for the Acp locus. Overall comparison of allele frequencies revealed significant differences for four loci, although the value of was low (0.007). At a lower geographical scale, two situations were observed. Populations from France and Portugal showed significant differences when comparing allele frequencies, although was low (0.0099). On the other hand, in northern and western Africa, no significant difference exists even when comparing populations located on either side of the Sahara desert. Results are discussed in relation to the migratory abilities of the species.
Environmental Toxicology and Chemistry, 2005
The impact of conventional, organic, and integrated pest management (IPM) strategies of apple orc... more The impact of conventional, organic, and integrated pest management (IPM) strategies of apple orchards on the reproduction of the great tit Parus major was investigated during a three-year period in southeastern France. The colonization process, egg-laying dates, clutch sizes, and fledging success were similar among pairs of P. major nesting in orchards conducted under the three studied management strategies. However, the mean number of young produced per ha (orchard productivity) was significantly higher in organic orchards than in both conventional and IPM orchards. Such divergences between both fledging success and orchard productivity primarily resulted from higher densities of P. major nesting pairs, but also from lower rates of nest abandonment during incubation in organic orchards. We suggest that intensive pesticide use under both IPM and conventional managements may have resulted in a substantial reduction in insect prey availability that enhanced intraspecific competition, which then led to failure in reproduction in pairs with low competitive ability. Our results highlight the relevance of P. major in assessing the environmental impact of apple orchard management strategies.
Agriculture, Ecosystems & Environment, 2013
Pest control that results from the activity of naturally occurring parasitoids is an important se... more Pest control that results from the activity of naturally occurring parasitoids is an important service that could help reduce pesticide use. We analyzed parasitism in codling moth diapausing larvae from a total of 122 apple orchards in southeastern France during five consecutive years (2006)(2007)(2008)(2009)(2010) in relation to the agronomic and land cover characteristics at both the local and landscape levels. Three species of hymenoptera parasitoids were observed, including two primary (Braconidae and Ichneumonidae) and one hyperparasitoid (Perilampidae) wasps. Parasitoid community compositions differed according to the year (in term of the relative abundance of the primary parasitoid species) and the presence of windbreaks and spontaneous hedgerows around the orchards (in terms of the relative abundance of primary vs. hyperparasitoid species). The parasitism rates were globally low in all orchards each year (<4.5% in average), but they were significantly higher in organic orchards than in conventional orchards as well as in orchards surrounded by a low proportion of conventional orchards in a 250 m vicinity. These results are discussed here in terms of biocontrol enhancement and conservation.
Agriculture, Ecosystems & Environment, 2013
Abstract The low sustainability of pesticides calls for alternative pest control practices. Among... more Abstract The low sustainability of pesticides calls for alternative pest control practices. Among these, the conservation of pest natural enemies is governed both by the local farming practices and by the presence of resources in the surrounding landscape. We ...
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Papers by Jean-françois Toubon