CONTAMINATION BY THE SHARKA VIRUS IN FRANCE : A SYNTHESIS
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The sharka is a vegetal disease native from Eastern Europe. Also called Plum-Pox-Virus, the sharka contaminated tree of the prunus type and other vegetals such as the XXX, tobacco, nettle, which become repositories for the virus.
In France, there are two strains of sharka, the Dideron and the Markus. The D strain is weakly infectious and slowly affects the trees it contaminated. The M strain is strongly infectious and contaminates a tree in three years in average if the tree is adult. For young trees the cycle is faster. The D strain is equally affecting plum trees, apricot trees, and peach trees; for unknown reasons, the M strain seems to be preferentially affecting peach orchards. Because of its strong infectiousness, the M strain expands its area of infection in concentric circles from the center of the infection, the pace of expansion of this area is of 1 kilometer a year, depending on the opportunities available.
The spread of sharka in France started in the 1960’s. Indeed, The D strain appeared in the end of the 1960’s, while the presence of the M strain is confirmed with certainty in 1984 in Salon de Provence. The L’Institut National de la Recherche Agronomique (INRA – National institute for agronomic research) asserts that the M strain was already present in France before 1980.
From 1980 on, the INRA imported thousand of cultivars from Eastern European countries, which are heavily infected by the sharka, into its Bordeaux located center “La Grande Ferrade”. However, the INRA did not systematically tested the imported plants, but only 2 to 3% of those. After implantation, some of the plants appeared to be infected. One cannot certify that the M strain entered in France through this channel, but there are strong presumptions to this effect.
Even though a sharka epidemics already started in 1980 at the Bordeaux “La Grande Ferrade” center, the INRA multiplied in green house the imported plant and sent them by lots in other INRA experiment sits and to the Centre Technique Interprofessionnel pour les fruits et légumes (CTIFL – Interprofessional technical center for fruits and vegetables), all of whom are located in fruit producing areas. This was done in the framework of stade A certification. A few of these lots proved to be infected by the sharka virus between 1980 and 1993.
The first contamination by the sharka virus was found in Salon de Provence in 1984, were it is established that the virus came from INRA’s experimental orchards and contaminated adjacent privately owned orchards. It was later found that the virus was from the M strain.
In 1986, the INRA started to acknowledge that some of its experimentation sites were contaminated by the virus.
In 1987, INRA orchards in the Pyrénées Orientales started to show contamination by the M strain of the sharka virus. They were followed in 1989 by privately owned orchards adjacent to the INRA site in Gotheron, Drôme that also show signs of contamination as did orchards adjacent to other INRA sites in Gard in 1990.
In the 1990’s, sharka contamination in privately owned orchards extended around all experimentation sites that previously received lots from the Bordeaux “La Grande Ferrade” site, to the exception of the CTIFL. Ever since, contamination by the virus geometrically increased, and it is known that it is mostly by the M strain. Contamination was also even more extended after the creation of secondary contamination sources.
Until 1993, efforts against sharka organized by the French state were mostly directed against the D strain. Indeed, the sharka disease was listed since 1970 among the diseases to be eradicated. The SPV (Service de Protection des Végétaux – Service of protection of vegetal strains) used the method of uprooting trees in infection areas and destroy them by fire. This method has been very successful against the weakly contaminating strain D of the sharka. It was applied with no result in 1986 in Salon de Provence.
In 1986, the SPV decided to stop searching for sharka at tree owners and instead concentrate its action in a radius of 900 meters around tree growers and in the same area around experimental sites owned by INRA.
In 1989, the Ministry of Agriculture and Fisheries decided not to launch an eradication campaign against sharck and that confinement measures were sufficient. It estimated that the INRA would discover sharka resistant prunus trees “within 10 years”. The Ministry also decided that the search for contaminated trees, to that date in charge of the SPV, would instead be “delegated” to orchard owners, without taking measures to prepare them or inform them about the M strain of the sharka virus.
In 1993, the Ministry of Agriculture and Fisheries defined the principles of a “collective and mandatory eradication effort”. The first element of this effort is based on measures aimed at confining the virus. The first step is a visual inspection that identifies sick trees showing signs of the disease. The second step is the uprooting of sick trees. When the share of contaminated tree in a field is less than 10%, only those have to be uprooted ; after the 10% threshold, the whole field needs to be uprooted and the trees burnt. Financial compensation that were initially granted were gradually decreased until their cancellation in 2005, as the size of affected areas kept on growing. The decisions to uproot orchards are made by the SPV with the assistance of the Prefecture (local representation of central government). A body named FREDEC was put in charge of the inspections, the cost of which is paid by half by the owner of the contaminated orchard. This body was later renamed Fédération Régional de Défense contre les Organismes Nuisibles (FREDON – regional federation of defense against crop threatening organisms). The second element rested on INRA finding new trees varieties that are resistant to sharka.
Since 1993, the Ministry has persisted in its policy of inspection and uprooting in order to “confine” the disease, assuming that the only way out is for INRA to create tree strain that are resistant to the sharka virus. Former Minister of agriculture, Mr Dominique Busserau was nevertheless informed, notably by the Derrien Report, that only the creation of an area of totally free of sharka could efficiently fight sharka. The policy of “collective and mandatory eradication effort” as established only reduces the multiplication of contaminated trees but does not slow down the extension of contaminated areas.
Surprisingly, state representatives claim that the “collective and mandatory eradication effort” is efficient for reducing the prevalence of the virus to the extent that “the agriculture profession is durably committed”. This is what they explain to orchard owner and to representative of other EU countries, while basic knowledge of the virus and elementary logic suggests otherwise as we will soon see.
Some professional organizations such as the Chambers of Agricultures and the Fédération Départementale des Groupements de Défense des Organismes Nuisibles (FDGDON – District federation of groups of defense against crop threatening organisms) claim that orchard owners “can live with the sharka” if they apply the procedures of inspection and uprooting laid out by the Ministry of agriculture.
Actually, the M strain is so infectious that even the most assiduous inspection cannot eradicate all contaminated tree in an orchard. Indeed, the inspection is visual, and made by identifying the symptoms shown by contaminated trees. However, contaminated trees only show symptoms 3 year in average after having been contaminated and, during that period, they are already contaminating other healthy trees. Visual inspection is therefore missing many contaminated and contaminating trees.
Owners of orchards contaminated have been suing the INRA and the French state at administrative courts in order to be compensated for the losses due to the introduction and extension of the M strain in France. According to those orchard owners, the virus arrived in 1980 with the trees imported by INRA, which in turn multiplied and disseminated the disease to its local experimentation sites in the 1980’s. Although the INRA gradually came to know about the contamination, the institute has not been reacting seriously or efficiently against the contamination of its own orchards. The INRA did not either worry for the risks being run by orchards located in the proximity of its sites. As a consequence, hundreds of orchard owners were put out of business. Moreover, the INRA is claiming not to be responsible of the introduction of the M strain in France and of further contamination.
Regarding the grievance against the French State, suing orchard owners are reproaching the behavior of the SRPV services which was late to react (rapidly and efficiently), before pulling out gradually of inspection and eradication efforts. Moreover, the Ministry of Agriculture is keeping on promoting its policy of “collective and mandatory eradication effort” even though it can neither confine nor fight the highly virulent M strain of the sharka virus that cannot be contained.
These grievances also regard the officially stated policy of the State that “consults” orchard owners but does not take their opinion into account and keeps on taking them responsible for contamination.
In conclusion, one can consider that the presence and extension in France of the two sharka virus strains has been influence for a long while by public policy. However, since public agencies have decided to underestimate the importance of the contamination and to under invest in its control and eradication, the epidemics has taken proportions that getting out of control. Nevertheless, public agencies have not updated their inconsistent and inefficient policies.