Change in relative frequencies of the three main genetic types of Botrytis cinerea (Group I, Group II vacuma, and Group II transposa) were monitored over time from 1998 to 2000 in three Bordeaux vineyards not treated with fungicides. During 2000, Group I isolates, detected mostly at flowering comprised only 2.5% of the entire population. Within Group II, the complementary frequencies of vacuma and transposa isolates differed significantly depending on grapevine phenological stages and organs. Every year and at all sites, including one noble rot site, transposa isolates dominated at every stage, particularly on overwintering canes and at harvest (greater than 86.7% on berries). The complementary frequency of vacuma isolates reached a maximum on senescing floral caps (between 23.5 and 71.4%) and then decreased significantly until harvest on leaves and berries. In pathogenicity tests on grape berries, transposa isolates were significantly more virulent than were vacuma isolates. Mycelial growth rate was negatively correlated with virulence, notably on leaves in transposa and with double resistance to the fungicides carbendazim and vinclozolin. In vacuma, this double resistance was positively correlated with virulence on leaves. Change in the vacuma and transposa frequencies was most likely caused by differences in saprotrophic and pathogenic fitness. Possible interactions between fungicide resistance profiles and fitness are discussed.

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Grapevine cultivars Cabernet Sauvignon (susceptible to Eutypa dieback), and Merlot (tolerant), were pruned three times during the dormant season (mid-December, mid-January and mid-February) and wounds on the 1-year-old canes were inoculated weekly with ascospores of Eutypa lata after pruning. No differences in susceptibility to infection were observed between cultivars, although in the vineyard they differed in symptom expression. Infection by E. lata varied with pruning date and the age of the pruning wound, and was higher and of longer duration with early pruning (December). At low temperature, infection of the pruning wounds by E. lata was increased, whereas the growth of other microorganisms was reduced. Moderate temperatures encouraged the growth of other microorganisms, notably Rhodotorula sp. This natural colonizer of grapevine pruning wounds was able to reduce the infection capacity of E. lata. It was more effective when inoculation with E. lata was carried out with low numbers of ascospores and when it was delayed until 14 days after application of the wound colonizer, infection being reduced by 95-100%.

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Les auteurs ont répertorié et analysé 260 cas de pourridiés en France sur vigne, arbres fruitiers et plantes florales, ornementales et à parfums.Vigne, L'armillaire est l'agent de pourridié le plus répandu et le plus grave sur la vigne, le pêcher, l'abricotier et Arbres fruitiers, l'amandier. Le pourridié laineux à Rosellinia est au contraire plus fréquent sur pommier, jasmin, lavande, Plantes florales, ainsi que sur les cultures florales non ligneuses. Le rosier, le cerisier, le figuier et l'olivier hébergent l'un et Pourridiés, l'autre parasite avec des fréquences comparables. Armillariella,Les symptômes des deux agents de pourridié sur divers hôtes font l'objet d'une description. Les deux R osell i n i a .champignons sont indiscernables par les symptômes qu'ils entraînent sur la partie aérienne des plantes parasitées. Par contre, l'aspect du mycélium agrégé souterrain permet généralement une distinction aisée entre les deux espèces. SUMMARYRoot-rot caused by Armillariella and Roseliinia in France on vine, orchard trees and flower crops. L Etiology and symptoms Vine,Orchard trees, About 260 cases of root-rot were observed and analyzed on vine, orchard-trees and flower crops in central and Flower crops, southern France. Root-rots, 'Apart from a single attack of Roesleria hypogea on vine, only two parasites were encountered : the honey Armillaria (ella) , fungus (Armillariella mellea sensu stricto = species « D » according to Korhonen) and the white root-rot Rosellinia.' fungus (Rosellinia necatrix (Hart.) Berl.). 'Armillariella is by far the more common on vine, peach, almond and apricots. It is a serious problem in the « Côtes-du-Rhône » vineyards and in the peach and apricots crops of Southern France. On the contrary, Rosellinia is the more frequent on apple, lavender, jasmine, carnation and all the fleshy flower plants. It sometimes causes important damage in apple orchards. On rose, cherry, fig and olive, both fungi are encountered. In two cases (on a fig-tree and on an olive-tree), Armillariella and Rosellinia were found together, attacking the same plant.The symptoms due to both fungi on several hosts are described. The symptoms on the foliage do not differ but the two parasites are generally easily distinguished by the appearance of aggregated mycelium inside the roots and collar.