Preliminary Studies on the Biology of «Phaeoacremonium»

Comparative microflora studies of one-year-old pruned and unpruned canes carried out during dormancy period over three consecutive years showed that Phaeoacremonium chlamydosporum was more frequently isolated from pruned than unpruned canes, while Phaeoacremonium aleophilum was found as much in pruned as in unpruned canes. Inoculations of pruning wounds made in two consecutive winters by suspensions of conidia of P. chlamydosporum and P. aleophilum showed that both fungi were able to invade through wounds during winter. Infections varied with pruning date and age of pruning wound, but were more serious and of longer duration with early pruning (December, January). Trapping studies showed that spores of P. chlamydosporum were captured throughout the whole year, while spores of P. aleophilum were mostly trapped during the vegetative period. Microscopic examination of adhesive tape applied to without bark zones of the canes showed the presence of conidia of P. aleophilum. From these studies, it emerged that only P. chlamydosporum is able to contaminate pruning wounds during winter. P. chlamydosporum and P. aleophilum may be propagated by infected canes in the nursery. They can be considered airborne fungi during a period of their biological cycle

Observation on Black Dead Arm in French Vineyards

Black dead arm was first identified in French vineyards in 1999. It produces symptoms in the vine wood, causing decline and eventually death. Previously, this disease was confused with esca because of the similarity of the foliar symptoms. Two forms of black dead arm, a mild and a severe form, were observed in French vineyards on Cabernet Sauvignon and Sauvignon. Isolations from 23 vines collected from four vineyards located in three viticultural districts of Bordeaux showed that the main fungi associated with the brown streaks were Botryosphaeria obtusa, B. dothidea and Trichoderma spp. Pathogenicity tests showed that B. obtusa and B. dothidea caused dark lesions on 1- year-old canes. Therefore, these two fungi merit further study to determine their role in causing black dead arm

Biological control in vineyards, use of antagonistic properties of Thrichoderma Harzianum Rifai against botrytis cinerea pers.

Biological control in vineyards, use of antagonistic properties of Thrichoderma Harzianum Rifai against botrytis cinerea pers.. International conference of integrated plant protectio

L'eutypiose de la vigne

 L'eutypiose de la vign

The «Hoja de Malvón» Grape Disease in Argentina

“Hoja de malvón” is the common name of a disease that has been observed in grapevines of Argentina since the beginning of the century. This paper reports the status of this disease in this country. The disease starts appearing in one of the plant arms. Leaves are smaller than normal, chlorotic and with the edges rolled downwards, the canes and current-year shoots show reduced growth and the clusters are smaller and sparser with berries of non uniform-size. In a cross sectional cut of the trunk two types of necrosis could be observed: a yellowish necrosis of soft consistency, or decay, in a central or sectorial position, surrounded by a black line and a brownish area; and a sectorial light brown necrosis of hard consistency, surrounded by a brown zone. Sometime, black spots are observed at the edge of the damaged areas. Isolations from trunk tissues of different cultivars of grafted and nongrafted plants, 3- to 30-year-old, were done in malt extract agar. Phellinus sp., Botryodiplodia sp. and Phaeoacremonium spp. (P. aleophilum, P. chlamydosporum and P. parasiticum) were isolated. Up to now, in vitro pathogenicity tests were conducted only with Phellinus sp., Botryodiplodia sp. and P. chlamydosporum, which were able to cause the decline and death of young plants. Research attempting to quantify the effects, and to study the factors influencing the appearance of the disease, is also being conducted. Only preventive practices are recommended for its control

The role of saprotrophy and virulence in the population dynamics of Botrytis cinerea in vineyards

International audienc

Possible relationship between aggressiveness of two <em>Eutypa lata</em> isolates and their polyamines and abscisic acid content

By HPLC analysis, we showed that myceliums of two Eutypa lata isolates cultivated in Enikson and Petersson medium culture synthesized polyamines (Putrescine, Spermidine and Spermine) and abscisic acid (ABA). ln this medium, myceliums of high virulent isolate (BXI-IO) produced fewer polyamines than less virulent isolate (BX 1-5) while inverse phenomenon was observed for ABA content. The two growth regulators were diffused in medium culture in which their levels increase with age of mycelium. In the end, variations of PA and ABA in myceliums show antagonist effect of the two growth regulators in Eutypa lata fungi

Les pourridiés à Armillariella et Rosellinia en France sur vigne, arbres fruitiers et cultures florales I. Etiologie et symptomatologie

National audienceAbout 260 cases of root-rot were observed and analyzed on vine, orchard-trees and flower crops in central and southern France. Apart from a single attack of Roesleria hypogea on vine, only two parasites were encountered : the honey fungus (Armillariella mellea sensu stricto = species « D » according to Korhonen) and the white root-rot 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.Les auteurs ont répertorié et analysé 260 cas de pourridiés en France sur vigne, arbres fruitiers et plantes florales, ornementales et à parfums. L’armillaire est l’agent de pourridié le plus répandu et le plus grave sur la vigne, le pêcher, l’abricotier et l’amandier. Le pourridié laineux à Rosellinia est au contraire plus fréquent sur pommier, jasmin, lavande, ainsi que sur les cultures florales non ligneuses. Le rosier, le cerisier, le figuier et l’olivier hébergent l’un et l’autre parasite avec des fréquences comparables. Les symptômes des deux agents de pourridié sur divers hôtes font l’objet d’une description. Les deux 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

Incidence oenologique du traitement biologique de la vigne par <em>Trichoderma viride</em> a l'egard de la pourriture grise

T. viride actif contre B. cinerea et d'autres champignons parasites de la vigne (A. carneus, P. frequentans, P. roqueforti) ne modifie ni la composition du moût ni sa couleur; il ne présente aucune action inhibitrice sur S. cerevisiae, Schizosaccharomyces et L. oinos. Par son activité polysaccharidase, son développement conduit à des vins plus limpides. A la dégustation, aucune variation significative n'apparaît par rapport aux vins témoins. L'antagonisme de T. viride peut donc être utilisé sans danger pour les caractères des moûts et des vins. +++ T. viride active against B. cinerea and other parasitic fungi of the vine (A. carrneus, P. frequentans, P. roqueforti) modifies neither the must composition nor its colour : it has no inhibitory influence concerning S. cerevisiae, Schizosaccharomyces and L. oinos. By the use of its polysaccharidase activity its development gives wines with better limpidity. When tasting no significant variations appear when comparing with reference samples. So the antagonism of T. viride can be used without any danger for the must and wines characters