Jondreville C.,French National Institute for Agricultural Research |
Jondreville C.,University of Lorraine |
Lavigne A.,FREDON |
Jurjanz S.,French National Institute for Agricultural Research |
And 6 more authors.
Science of the Total Environment | Year: 2014
The former use of chlordecone (CLD) in the French West Indies has resulted in long-term pollution of soils and subsequently of food chains. In contaminated areas, free-range ducks used to control weeds in orchards may be exposed to CLD through polluted soil ingestion. The question arises whether they may be consumed. Muscovy ducks were raised on a guava orchard planted on a soil moderately contaminated (410. μg CLD/kg dry matter). Ducks were raised indoor up to 6. weeks of age and allowed to range freely outdoors thereafter. Twenty-nine females were sequentially slaughtered by groups of 2 to 5 ducks, after 4, 16, 19, 22 or 26. weeks spent in the orchard or after 16-17. weeks in the orchard followed by 3, 6 or 9. weeks in a closed shelter for depuration.CLD concentration increased from 258 to 1051, 96 to 278, 60 to 169 and 48 to 145. μg/kg fresh matter (FM) as the exposure through grazing increased from 4 to 22. weeks, in liver, abdominal fat and leg with and without skin, respectively. Eggs collected in the orchard contained up to 1001. μg CLD/kg FM. All these values exceeded the Maximum Residue Limit (MRL) of 20. μg/kg FM. CLD concentration in all tissues was divided by around 10 within the 9-week confinement period. Despite this quite rapid decontamination, it is estimated that 12-13. weeks would be required to achieve the MRL in liver and in eggs, and 5-6. weeks in leg muscle. Such durations would be too long in practice. Thus, the consumption of products from free-range ducks should be avoided, even in areas mildly contaminated with CLD. © 2014 Elsevier B.V.
Deberdt P.,CIRAD |
Guyot J.,CIRAD |
Coranson-Beaudu R.,CIRAD |
Launay J.,CIRAD |
And 6 more authors.
Phytopathology | Year: 2014
Although bacterial wilt remains a major plant disease throughout South America and the Caribbean, the diversity of prevalent Ralstonia solanacearum populations is largely unknown. The genetic and phenotypic diversity of R. solanacearum strains in French Guiana was assessed using diagnostic polymerase chain reactions and sequence-based (egl and mutS) genotyping on a 239-strain collection sampled on the families Solanaceae and Cucurbitaceae, revealing an unexpectedly high diversity. Strains were distributed within phylotypes I (46.9%), IIA (26.8%), and IIB (26.3%), with one new endoglucanase sequence type (egl ST) found within each group. Phylotype IIB strains consisted mostly (97%) of strains with the emerging ecotype (IIB/sequevar 4NPB). Host range of IIB/4NPB strains from French Guiana matched the original emerging reference strain from Martinique. They were virulent on cucumber; virulent and highly aggressive on tomato, including the resistant reference Hawaii 7996; and only controlled by eggplant SM6 and Surya accessions. The emerging ecotype IIB/4NPB is fully established in French Guiana in both cultivated fields and uncultivated forest, rendering the hypothesis of introduction via ornamental or banana cuttings unlikely. Thus, this ecotype may have originated from the Amazonian region and spread throughout the Caribbean region. © 2014 The American Phytopathological Society.
Lavigne A.,FREDON |
Dumbardon-Martial E.,FREDON |
Lavigne C.,CIRAD - Agricultural Research for Development
Fruits | Year: 2012
Introduction. Because of the humid tropical conditions, weed control is an important and permanent job in the outlay of a fruit producer in the West Indies. The practice of chemical weed control is to date the cheapest, but the recurring use of herbicides in the orchards of Martinique leads to soil erosion and water pollution. To mitigate the use of herbicides, we tested the association of poultry with a productive orchard in order to control the weeds. Materials and methods. The system was installed on a plot of 700 m2 divided into seven plots of 100 m2. Two plots were the control treatments and were mowed with a brush cutter. Each of the other five plots was subjected to five geese grazing for a week, then to 20 chickens grazing during the following week, then the plot was left without poultry for three more weeks. Three cycles of such rotations were observed (4 months). Biomass production by botanical groups (Poaceae, Cyperaceae and others) in the experimental plots was measured each week for four months. A monthly index of recovery by botanical group was noted. Results. The total biomass of the herbaceous cover decreased on grazed plots, which allowed the biological control of weeds for four months. Species diversity decreased because of the selection made by poultry for food and cover was homogenized by the percentage increase in biomass of Cyperaceae in the total biomass. This group, the least palatable for poultry, thus flourished on all plots grazed. Discussion. Poultry grazing, particularly geese, proved to be a promising method for controlling weeds in orchards. However, in the case of a high proportion of unpalatable species in the herbaceous cover, other weed control methods should be combined. The installation of a grass cover composed of a mixture of cover crops adapted to the combination of orchard and poultry as well as better management of the animal rotation should be considered to optimize this technique. © 2012 Cirad/EDP Sciences.