97 research outputs found
Tavelure - RĂ©duire ses traitements
«Bien positionner ses traitements au printemps est la clĂ© pour maĂźtriser la tavelure avec un minimum de phyto », introduit Laurent Jamar, chercheur belge. Il est vrai que, pour pouvoir contaminer une feuille, une fleur ou un fruit, le champignon responsable de la tavelure a besoin de la prĂ©sence dâun film dâeau pendant un certain laps de temps, variable selon la tempĂ©rature : la protection phytosanitaire doit ainsi ĂȘtre ajustĂ©e aux conditions pĂ©doclimatiques, dĂ©finies si possible au niveau du verger. « Pour cela, deux outils sont essentiels : une station mĂ©tĂ©o, qui enregistre les donnĂ©es localement heure par heure, et un modĂšle de simulation des infections, qui analyse les donnĂ©es mĂ©tĂ©os enregistrĂ©es. Assurer une protection vis-Ă -vis des contaminations primaires Ă©vite ainsi toute intervention pendant lâĂ©tĂ© ! », poursuit le chercheur
Innovative strategies for the control of apple scab (Venturia inaequalis [Cke.] Wint.) in organic apple production
The aim of this thesis, conducted over six growing seasons (20032008), is to define new measures for reducing the use of fungicides and in particular, copper fungicides, for the control of apple scab (V. inaequalis) in organic apple production. Special emphasis is put on primary scab infection control during spring season. An original approach is proposed for defining a specific spray timing involving spraying during the infection processes, especially before fungal penetration, determined by the RIMpro software warning system. This âduring-infectionâ spray strategy allows reducing from 30 to 50% the amount of fungicide usually used for effective apple scab control, on high scab-susceptible cultivars. The field study shows that six alternative products (e.g., potassium bicarbonate and lime sulphur), among 60 products tested, have the potential to reduce copper use. However, copper use, even with low doses, seems to be still necessary in presence of scab-susceptible cultivars. The results obtained in these experiments could not be attributed to the specific technical performances of the tunnel sprayer used, which however, offer valuable environmental benefits. On the basis of the present study, the organic management system seems a good farming approach for maintaining soil quality with regard to biological indicators. This work shows and draws attention to the fact that (i) planting cultivars with polygenic scab-resistance traits, (ii) increasing emphasis on sanitation practices aimed at reducing initial inoculum in autumn, and (iii) applying an accurate spray strategy in spring, as defined in the present study, are the three most promising approaches for substantial further reductions in protection products fully compliant with international organic crop production standards
CREATION ET EXPERIMENTATION DE VARIETES DE POMMES ADAPTEES A LâAGRICULTURE BIOLOGIQUE
Our apple breeding program is based entirely on the results of our work to safeguard, evaluate and valorize the rich heritage of apple tree genetic resources in our regions. Since 1975, no fewer than 1800 introductions have been collected in our collections and, taking into account duplicates, errors and synonyms, this represents a total of about 850 distinct cultivars. These are systematically evaluated in experimental orchards that do not undergo any treatment. Some cultivars that are highlighted for their high level of resistance to the main diseases as well as for their agronomic and quality characteristics of trees and fruits are used as parents. Our priorities are mainly focused on the expansion of the apple's genetic base, polygenic resistance to the main diseases (scab, powdery mildew, canker) and a whole series of characteristics present in certain old and peasant varieties such as long natural conservation, rusticity, robustness, frugality, nitrogen efficiency, tree architecture and the nutritional qualities and properties of the fruit. These parents are then crossed with varieties, often more commercial, which offer advantages in terms of speed of fruiting, yield, flesh quality and tree architecture. The current plant breeding program is based on extensive methodological work that has been developed specifically to select materials with partial disease resistance that express good potential for adaptation to simple and 'low-input' crop conditions. About sixty elite selections from our work are currently being tested in organic farming and are compared with 48 other new commercial varieties in order to look for varietal alternatives that are much better adapted to organic production than those currently being grown. Partial results of about twenty selections and varieties are presented, including results relating to the sustainability of a panel of varieties carrying the Vf gene
RECHERCHE DE METHODES ALTERNATIVES DE PROTECTION VIS-A-VIS DES GLOEOSPORIOSES EN PRODUCTIONS FRUITIERES BIOLOGIQUES
Les gloeosporioses représentent les principales maladies fongiques de
conservation de la pomme et de la poire en Europe de lâOuest, responsables de pertes en
longue conservation. Plusieurs espĂšces en sont responsables, mĂȘme si lâune, Neofabraea
alba est dominante dans nos régions. La majorité des surfaces plantées sont constituées
de variétés moyennement à trÚs sensibles à ces maladies. La protection contre les
gloeosporioses repose essentiellement sur des traitements en pré-récolte mais en
agriculture biologique, il nâexiste pas Ă ce jour de produit reconnu efficace. Les
principales techniques alternatives sont le traitement Ă lâeau chaude en post-rĂ©colte et le
stockage au froid sous atmosphÚre contrÎlée. On ne connait pas de méthode
prophylactique pour N. alba. Lâobjectif de cette Ă©tude est de mesurer, durant deux
saisons de rĂ©colte (2013-2014), lâimpact dâune formulation Ă base dâargiles calcinĂ©es
(Mycosin) et dâun activateur de dĂ©fense naturelle (Vacciplant) sur le dĂ©veloppement des
gloeosporioses durant la période de conservation post-récolte. Les premiers essais
(annĂ©e 1), montrent que le Mycosin (six applications prĂ©-rĂ©coltes), a rĂ©duit lâincidence
de la maladie observée à la fin du mois de mars, de 56, 54 et 50% sur les variétés
Pinova, Pirouette et Reinette des capucins respectivement. Par contre, le Vacciplant
(deux applications prĂ©-rĂ©coltes) nâa pas eu dâimpact significatif sur la maladie.
Lâanalyse des fruits correspondant Ă la deuxiĂšme annĂ©e dâessai doit ĂȘtre rĂ©alisĂ©e durant
le premier trimestre 2015
Strategies to reduce copper use in organic apple production
Various strategies for controlling apple scab (Venturia inaequalis) were studied under field conditions over two growing seasons. An experimental organic orchard, designed especially for this trial, was planted with four partially scab-resistant cultivars ('Rubinstep-Pirouette', 'Reinette des Capucins', 'Reinette de Waleffe' and 'Pinova', which was used as the control) and four Vf scab-resistant cultivars (Topaz, Zvatava, Initial and JN 20/33/58). As the virulent scab race 7 is present in Belgium, one of the objectives was to test strategies to prevent Vf resistance breakdown. In order to drastically limit copper use, seven spray treatments were tested, including: 1. wettable sulphur (WS), 2. copper and wettable sulphur combined (CS), 3. wettable sulphur and lime sulphur combined (WSLS), 4. potassium bicarbonate (PB), 5. silicon (Si), 6. untreated control (Control) and 7. conventional fungicide control (IFP). The timing of fungicide applications was determined by the RIMPRO software warning system on the presence of airborne scab ascospores in orchards, taking into account forecasted weather conditions. A prototype of the 'tunnel sprayer' machine was used to apply fungicides. Compared with the control, fruit scab severity on cv. Pinova was significantly reduced by 99, 99, 91 and 68% in 2003 and by 100, 100, 92 and 52% in 2004 on trees sprayed with IFP, CS, WSLS and PB, respectively. These results were obtained with only 10 spray applications at lower fungicide rates despite the higher scab infection pressure in 2004. Good timing seems to be the most important factor in a spray treatment. Most of the treatments (IFP, CS, WSLS, WS and PB) also significantly reduced powdery mildew (Podosphaera leucotricha) infections. In both years, treatments with sulphur, copper and lime sulphur did not cause any phytotoxicity on leaves and fruits. A quantitative provisional apple scab control programme using copper and wettable sulphur was set up, including all potential climatic situations and degrees of infection risk in Belgium. The potential use and limits of potassium bicarbonate as an active substance for controlling apple scab and powdery mildew are discussed
PRATIQUES ALTERNATIVES AUX PRODUITS PHYTOSANITAIRES EN ARBORICULTURE â EFFET DE LA GESTOIN DES LITIERES DE FEUILLES EN AUTOMNE SUR LE DEVELOPPEMENT DE LA TAVELURE DU POMMIER EN VERGER BIOLOGIQUE
La tavelure du pommier causĂ©e par Venturia inaequalis reprĂ©sente une prĂ©occupation majeure dans les vergers des rĂ©gions Ă climat tempĂ©rĂ© de lâEurope. Le but
de cette Ă©tude, rĂ©alisĂ©e dans un verger biologique du CRA-W, est dâĂ©valuer lâeffet de la rĂ©duction de lâinoculum primaire prĂ©sent dans les feuilles mortes sur le dĂ©veloppement
de la tavelure. LâexpĂ©rience est composĂ©e de trois modalitĂ©s appliquĂ©es en automne, lâune basĂ©e sur lâandainage et le broyage des feuilles au sol (B), la seconde sur le
ramassage des feuilles et lâenfouissement des feuilles restantes (R), et la troisiĂšme
maintenue comme témoin sans intervention (T). Par rapport aux parcelles sans
intervention (T), une réduction moyenne respectivement de 42 et 75% des vols
dâascospore est enregistrĂ©e lâannĂ©e suvante sur les parcelles âBâ et âRâ. Sur la variĂ©tĂ©
âInitialâ, la plus sensible, lâincidence moyenne de tavelure sur fruits Ă©quivaut
respectivement Ă 15, 13 et 4% sur les parcelles âTâ, âBâ et âRâ. Dans le mĂȘme verger
expérimental, dont 20% de la superficie est occupée par des zones de compensation
Ă©cologique composĂ©es dâarbustes et dâune strate herbacĂ©e fleurie, les populations de
pucerons cendré (Dysaphis plantaginea), principal bio-agresseur des vergers de
pommier, sont maintenues naturellement en desous du seuil de nuisibilité sans aucun
traitement insecticide, depuis 2003, deuxiĂšme annĂ©e de vie du verger, jusquâen 2014
Mise en place dâun plan de recherche pour le dĂ©veloppement de lâagriculture biologique en RĂ©gion Wallonne
LâAB a permis le dĂ©veloppement de nombreuses innovations en agriculture et constitue un exemple particuliĂšrement avancĂ© de mĂ©thodes accordant une grande attention Ă la durabilitĂ© ainsi quâaux impacts environnementaux et sociĂ©taux. Les donnĂ©es rĂ©centes en matiĂšre de dĂ©veloppement de lâAB en Wallonie ont montrĂ© que les superficies affectĂ©es Ă ce mode de production ont Ă©tĂ© multipliĂ©es par 2,7 entre 2005 et 2012 et atteignent ainsi un total de 7,6% de la SAU. Durant cette mĂȘme pĂ©riode, le nombre dâexploitations converties Ă ce mode dâexploitation a Ă©galement Ă©tĂ© multipliĂ© par 2,2, ce qui reprĂ©sente aujourdâhui plus de 1100 entreprises affiliĂ©es Ă un organisme de contrĂŽle. Au niveau de la consommation, la part des produits bio dans les achats des mĂ©nages est Ă©galement en forte augmentation. Durant la pĂ©riode 2004-2010, elle a Ă©tĂ© multipliĂ©e par un facteur de 1,7. Suite Ă ce constat, un "Plan stratĂ©gique pour le dĂ©veloppement de lâAB en Wallonie Ă lâhorizon 2020" vient dâĂȘtre approuvĂ© par le Gouvernement Wallon. Il vise notamment Ă doubler les surfaces conduites en AB. Parmi les objectifs de ce plan, figure la nĂ©cessitĂ© dâaccroĂźtre et de structurer les efforts en matiĂšre de recherche, dâencadrement et de vulgarisation spĂ©cifiques Ă ce secteu
Cultures maraĂźchĂšres aprĂšs destruction de prairies permanentes: risques environnementaux et intĂ©rĂȘts agronomiques
La derniÚre version du Programme de Gestion Durable de l'Azote (PGDA III) entré en application en Juin 2014, interdit de cultiver des légumes pendant une période de deux ans, aprÚs destruction de prairie permanente. Cette interdiction est considérée comme un frein au développement du maraßchage biologique. Est-elle totalement justifiée? Une situation bien gérée peut-elle permettre de limiter les risques de lixivation de nitrate
Scab control in organic apple production: conclusions of an eight year study in temperate weather conditions
The objective of this study, conducted over eight growing seasons (2002â2009), is to identify an innovative way for reducing the use of fungicides and in particular, copper fungicides, for the control of apple scab (V. inaequalis) in organic apple production. Special emphasis is put on
cultivar traits, sanitation practices and primary scab infection control during spring season. An original
approach is proposed for defining a specific spray timing involving spraying during the infection processes, especially before fungal penetration, determined by the RIMpro software warning system.
This âduring-infectionâ spray strategy allows reducing from 30 to 50% the amount of fungicide usually used for effective apple scab control, on high scab-susceptible cultivars. Potassium bicarbonate, lime sulphur, and three plant extracts such as peel orange extract, among 60 alternative products tested, have the potential to reduce copper use. However, copper use, even with low doses, seems to be still
necessary in presence of scab-susceptible cultivars. The results obtained in these experiments could not be attributed to the specific technical performances of the tunnel sprayer used, which however, offer valuable environmental benefits. This work shows that (i) planting cultivars with polygenic scabresistance traits, (ii) increasing accent on sanitation practices aimed at reducing initial inoculum in autumn, and (iii) applying an accurate âduring-infectionâ spray strategy in spring, are the three most promising approaches for substantial further reductions in protection products fully compliant with international organic crop production standards
EVALUATION DE DEUX STRATEGIES VISANT A REDUIRE LâUSAGE DU CUIVRE EN PRODUCTION BIOLOGIQUE DE POMME DE TERRE ET DE FRUITS A PEPINS
Le cuivre est un des seuls produits efficaces homologués en agriculture
biologique (AB) contre le mildiou de la pomme de terre (Phytophthora infestans) et la
tavelure du pommier (Venturia inaequalis) et du poirier (Venturia pirina). Cependant il
peut accuser une certaine toxicité envers les macro- et micro-organismes du sol et
aquatiques si il est utilisĂ© Ă forte dose. Câest pourquoi dans lâattente dâune alternative
aussi efficace, il est nécessaire de trouver une maniÚre de réduire les doses appliquées
tout en maintenant une protection efficace de la culture. Lâobjectif de cette Ă©tude est de
(i) comparer lâefficacitĂ© de trois formulations du cuivre utilisĂ©e pour lutter contre le
mildiou de la pomme de terre et la tavelure du pommier et (ii) dâĂ©valuer lâimpact de la
pulvĂ©risation localisĂ©e sur les rangs pour rĂ©duire lâusage du cuivre dans la lutte contre le
mildiou de la pomme de terre. Les essais ont montrĂ© que lâefficacitĂ© des produits
cupriques utilisĂ©s nâest pas amĂ©liorĂ©e par la formulation et que la diminution du dosage
de cuivre, par des traitements localisĂ©s sur les rangs en dĂ©but de vĂ©gĂ©tation, nâa pas
diminuĂ© lâefficacitĂ© gĂ©nĂ©ral de la protection vis-Ă -vis du mildiou, ni les rendements en
pomme de terre. Les essais sur pomme de terre se sont appuyés sur une stratégie de
fractionnement de lâapport du cuivre en douze applications au lieu de quatre maximums
prévues par la législation
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