Efficacy and foliar absorption of flupyrsulfuron-methyl and prosulfocarb applied alone or in mixture on Lolium multiflorum and wheat

Des melanges de flupyrsulfuron-methyle et de prosulfocarbe concus pour ameliorer la lutte contre Lolium multiflorum Lam. dans le ble (Triticum aestivum L.) ont ete etudies grâce a des essais biologiques sur plantes entieres et a des etudes de penetration foliaire. Dans les essais biologiques, le flupyrsulfuron-methyle et le prosulfocarbe etaient appliques a 6-7 doses, seuls ou en melange dans les rapports 1:400, 1:40 et 1:4 (p/p). Les courbes de reponse etaient ajustees au moyen de modeles logistiques et l'action conjuguee etait evaluee par la methode des isoboles. Dans les essais biologiques conduits en serre sur L. multiflorum, l'action conjuguee des melanges montrait une additivite de do…

Côté mauvaises herbes, tir de barrage sur trois envahissantes

National audience; Les plantes envahissantes sont évoquées à la conférence sur les zones non agricoles de l'AFPPà Avignon les 11 et 12octobre 2006. La situation à leur égard en France et en Europe est présentée, notamment les dispositions réglementaires et l'identité des 34 principales espèces. Deux communications traitent de l'ambroisie à feuille d'armoise Ambrosia artemisiifolia. Un point sur les méthodes de lutte mécanique, chimique, etc.) insiste sur l'intérêt de la prévention (enherbement, etc.)et de la concertation entre acteurs agricoles et non agricoles. Des essais de lutte chimique (glyphosate ou glufosinate-ammonium en 2004 et 2005, les montrent équivalents et intéressants en débu…

Oils for weed control: Uses and mode of action

The role of oils in herbicide treatments is reviewed, both in terms of their own intrinsic activity and of their enhancement of the performance of other herbicides. The phytotoxicity of oils can be related to their physical properties. Their efficacy as adjuvants can vary with the plant /pesticide combination involved, and differences may also be observed between oils of mineral and vegetable origin. The possible mechanisms involved in the enhancement of activity by oils are discussed and areas of work that might elucidate these further are indicated

Réduction du nombre de molécules herbicides : conséquences par culture. Problématique particulière de la gestion de la flore adventice

All national and European legislations contribute to the present reduction in the available herbicide number. This evolution leads to the decrease in the number of chemical families and to a dramatic reduction of the number of modes of action in some crops or crop rotations. This could lead to the selection of new herbicide resistances. So we may find contrasted situations: crops weeded with only a few herbicides or some herbicides used in almost all crops. The drastic reduction in the available active ingredients without taking into account the benefit-risk ratio or without planning realistic alternative solutions may create tougher agronomic constraints. A data base built up from all the …

Suppression of Ambrosia artemisiifolia pollen and seed production by herbicides: identification of a susceptible growth stage

International audience

Les paradoxes du glufosinate et glyphosate. Comportement dans l'ambroisie à feuilles d'armoise

BEHAVIOUR OF GLUFOSINATE ANDGLYPHOSATE IN COMMONRAGWEED:APPARENT PARADOXAND SURPRISES We examined the foliar epidermis of commonragweed (Ambrosia artemisiifolia L.) plants and studied the behaviour of the herbicides glufosinate and glyphosate in this species. Both leaf surfaces exhibited 3 types of trichomes, according to their size and shape. Epicuticular waxes appeared amorphous, which may explain high levels of spray retention. Glufosinate and glyphosate were rapidly and almost completely taken up by common ragweed leaves; half maximum uptake was nearly reached after 5 and 3 h, respectively. The longest trichomes were stained with AgN03, indicating the presence of hydrophilic domains, wh…

Effects of the herbicides Benzoylpropethyl and flampropisopropyl on rat liver mitochondria : an alteration in membrane fluidity ?

Abstract The action of the herbicides benzoylpropethyl and flampropisopropyl, and the corresponding unesterified acids was studied in rat liver mitochondria. The herbicides were found to (a) inhibit the mitochondrial electron transfer in complex III or at the level of ubiquinone (I50 of 4 nmol mg protein−1 for flampropisopropyl and 18 for benzoylpropethyl with succinate as a substrate); (b) have an additional (however less sensitive) site of inhibition near succinate dehydrogenase; and (c) interfere with energy transfer. Sensitivity was increased 2- (benzoylpropethyl) and 3.5-fold (flampropisopropyl) as the rats age increased from 12–13 weeks to 23–26 weeks. The free acids were far less eff…

Résistance au glyphosate, ce qui est prouvé

National audience

Historique de l'utilisation des herbicides en France: premières analyses

A data base on the herbicides used in France since 1961 has been built up from the phytosanitary index annually edited by the Association de Coordination Technique Agricole (ACTA). This data base gives the number of active ingredients, associations and commercial products registered every year and for each crop. We also gathered the modes of action, the way of absorption sites and the species susceptibility. Since 1961, 215 molecules have been registered. The number increased regularly with a maximum of 138 in 2002 and only around 100 remain in 2010. The evolution of the number of modes of action available for weed control in wheat is discussed.

Biological evidence for a 1:1 Ca2+:glyphosate association in deposit residuals on the leaf surface of barley

It has long been known that calcium ion antagonizes glyphosate, but it was not clear whether the stoichiometry of their interaction is 1:1 or 1:2. Two independent methods were used to determine which stoichiometry was the most probable. First, dose-response curves of barley (Hordeum vulgare L.) plants treated with glyphosate were determined in the presence of 0, 1.25, 2.5, 5 and 10 mM CaCl 2 . The doses of 'free' glyphosate (=not inactivated by calcium ion) were computed using the assumptions of 1:1 and 1:2 stoechiometries. The response curves were redrawn as a function of 'free' glyphosate. Analysis showed that the 1:2 hypothesis could be rejected, whereas the 1:1 hypothesis was highly pro…

History of chemical weeding from 1944 to 2011 in France: Changes and evolution of herbicide molecules

International audience; Herbicide development in France has been analysed from a historical and agronomical perspective. A database was built up from data collected from the archives of the Ministry of Agriculture Food and Fisheries and from French phytosanitary compendia edited since 1961 by the Association de Coordination Technique Agricole. Only herbicides used in cultivated areas were retained. The first organic synthetic herbicides were registered on cereals after the Second World War. Since 1944, a total of 225 herbicidal active ingredients have been registered in France. The number of active ingredients regularly increased with a maximum of 138 in 2002; 104 were still authorized in 2…

Uptake of triticonazole, during imbibition, by wheat caryopses after seed treatment

The uptake of 14C-labelled triticonazole by wheat caryopses during imbibition was investigated. The uptake from an aqueous solution appeared to be driven by mass flow rather than by accumulation in seed lipids. During treatment with a liquid seed-dressing preparation of triticonazole, c. 1 μg triticonazole per caryopsis (2·4% of applied triticonazole) entered the seed. During germination in soil, another c. 1 μg triticonazole per caryopsis entered the seed in 24 h. In killed seeds, no penetration was observed between 24 h and 72 h after the beginning of imbibition. After seed treatment and imbibition in soil, triticonazole appeared to be located in the seed coats and embryo, but not in endo…

An ethoxylated surfactant enhances the penetration of the sulfated laminarin through leaf cuticle and stomata, leading to increased induced resistance against grapevine downy mildew

International audience; Some β-1,3-glucans and particularly sulfated laminarin (PS3) are known as resistance inducers (RIs) in grapevine against the downy mildew. However, their efficacy in vineyard is still often too low, which might be caused by a limited penetration through the leaf cuticle following spray application. We used (14) C-sucrose uptake experiments with grapevine leaves in order to select a surfactant as saccharide penetration enhancer. Our results showed that though sucrose foliar uptake was low, it was strongly enhanced by Dehscofix CO125 (DE), a highly ethoxylated surfactant. Fluorescent saccharides were then produced and laser scanning microscopy was used to analyze their…

Gestions agronomique et sanitaire d'[i]Ambrosia artemisiifolia[/i] : acquisition de connaissances et test d'une stratégie de lutte à l'échelle d'un territoire

L’ambroisie (Ambrosia artemisiifolia L.) est une espèce invasive déjà fortement implantée en région Rhône-Alpes, et qui connaît une expansion croissante ailleurs en France. Du fait du caractère très allergénisant de son pollen, elle est devenue un problème de santé publique majeur. L'objectif principal du projet était de contribuer à réduire les allergies en améliorant la qualité de l’air via le contrôle de l’ambroisie par : - la mise au point et le test en conditions réelles d’une stratégie de maîtrise de l'ambroisie dans un paysage impliquant à la fois des acteurs agricoles et non agricoles, dans le cadre d’une opération pilote; - une contribution à l'aide à la décision publique grâce à d…

The experimental herbicide UKJ72J is an inhibitor of succinate oxidation in plant mitochondria

not received UKJ72J Herbicide Thiopyrimidine Plant mitochondria Inhibitor Succinate oxidation

Inhibition of succinate oxidation by the herbicide UKJ72J

Abstract The inhibitory activity of the herbicide UKJ72J on succinate oxidation in mitochondria from various plant species was studied. In monocotyledons (Gramineae: wheat, oat, maize; Liliaceae: onion, leek) succinate oxidation was affected only at high concentrations. Among dicotyledons widely differing sensitivities were found: in Solanaceae (tomato, potato, tobacco), Leguminosae (mung bean, soybean) and Compositae (sunflower) I 50 concentrations for UKJ72J inhibition were below 55 μM. In Cruciferae (turnip, cauliflowers Chenopodiaceae (lambsquarter, beetroot) and Compositae (endive) I 50 were between 100 and 250 μM, whereas in Rosaceae (apple, pear) and Umbelliferae (carrot, fennel) I 5…

Application foliaire et biodisponibilité des stimulateurs de défenses des plantes. Spécificités et limites en viticulture

IPMSPEINRAUBDOCT; Application foliaire et biodisponibilité des stimulateurs de défenses des plantes. Spécificités et limites en viticulture

The effect of substituted urea herbicides on the growth of excised tomato roots

Summary The action of 23 herbictdal substituted ureas on the growth of excised tomato roots was studied in order to determine whether there is a link between the effects of these herbicides on oxidative phosphorylation and on the growth of non-photosynthetic tissues. Fourteen of these herbicides were inhibitory; chlortoluron and TBU were stimulatory but only in the light. Substituted ureas known to affect plant mitochondria inhibited root growth but to a lesser extent than some which had no action on mitochondria. No clear relationship was found between actions on mitochondria and on root growth. It is suggested that targets other than photosynthesis and oxidative phosphorylation exist for …

Les actions du chlorfenprop-methyl sur l'integrite membranaire dans les mitochondries des plantes

Summary The action of chlorfenprop-methyl, chlorfenprop and its cysteine conjugate was studied on potato tuber mitochondria. Chlorfenprop-methyl altered membrane structure at 250 μM. leading to a loss of membrane integrity. Chlorfenprop and its cysteine conjugate were without any significant effects. From what is known about the rapid hydrolysis of chlorfenprop-methyl in plant tissues and from the results presented in this paper, it was deduced that alteration in intra-cellular membrane integrity is not a mechanism of phytotoxic action for chlorfenprop-methyl. Resume Les actions du chlorfenprop-methyl sur l'integrite membranaire dans les mitochondries des plantes Les actions du chlorfenprop…

Methomyl analogues with increased biological activity towards F7T maize mitochondria

Abstract Methomyl analogues were synthesized by substituting alkyl moieties (C 2 -C 21 ) in the place of the carbamic methyl. They were assayed on mitochondria isolated from male sterile (F 7 T) and male fertile (F 7 N) maize. They had no action on F 7 N mitochondria. The heptadecyl (C 17 ) and heneicosanyl (C 21 ) derivatives had no conspicuous effect on F 7 T mitochondria. By contrast, the ethyl, propyl, butyl, nonyl, tridecyl (C 13 ) and pentadecyl (C 15 ) derivatives had the same type of activity as Methomyl on F 7 T mitochondria, namely stimulation of NADH oxidation and inhibition of malate oxidation. Moreover, the concentration at which they were maximally effective decreased from 10 …

Résistance au glyphosate des soupçons cartographiés

National audience

Biological activity of the two geometrical isomers of methomyl on maize mitochondria

Abstract Methomyl ( S -methyl- N [(methylcarbamoyl)oxy]thioacetimidate), the active ingredient in lannate insecticide, gave a geometrical isomer after acid

A database for the herbicide use in France

SPEEAEcolDur; International audience

Les variétés végétales tolérantes aux herbicides, un outil de désherbage durable ?

Depuis 2009, des variétés de tournesol et de colza, dites « tolérantes aux herbicides » (TH), font leur apparition en France. Destinées à faciliter le désherbage, ces variétés résistent à un herbicide donné ce qui permet a priori d’appliquer l’herbicide sans risque pour la culture. La culture de telles variétés a suscité une contestation sociale se traduisant par l’arrachage de tournesols TH dénoncés comme « OGM cachés ». Dans ce contexte, les ministères chargés de l’Agriculture et de l’Environnement ont demandé à l’Inra et au CNRS de réaliser un bilan des connaissances disponibles sur l’ensemble des impacts de la culture de ces variétés.

Utilisation des variétés rendues tolérantes aux herbicides cultivées en France. Rapport d’expertise Anses. Saisine n°2015-SA-0063. mars 2020

Au cours des récentes décennies, parallèlement à la commercialisation de nouvelles substancesherbicides sélectives, s’est développée une démarche visant à produire des variétés végétales quitolèrent un ou des herbicides. Les variétés dépourvues de cette tolérance selon le cas sontdétruites par cet ou ces herbicides, ou voient leur croissance et leur développement perturbés.Du fait du caractère de tolérance de la plante, l’herbicide est applicable en post-levée, c’est-à-direaprès la levée2 de celle-ci. A ce stade de la culture, les adventices3 ont également levé. Lebénéfice escompté de cette approche est d’appliquer le traitement herbicide au moment adéquaten fonction du degré de présence de…

Lutte contre les mauvaises herbes en France, dix lustres en lumière : Analyse de 50 ans d’usage des herbicides tirée d’une « mine »

Historique des herbicides en France depuis la seconde guerre mondiale

National audience; Au lendemain de la seconde guerre mondiale, les herbicides ont joué un rôle important dans la réponse du monde agricole aux besoins alimentaires des populations, notamment grâce aux économies de main-d’œuvre et aux facilités de gestion qu’elles ont permises. Pourtant, aujourd’hui, l’agriculture intensive et productiviste fait l’objet d’une remise en cause du fait de son impact sur l’environnement, en particulier sur les ressources en eau (présence de nitrates, substances actives (SA) phytosanitaires). Face à la réglementation européenne et pour répondre aux préoccupations de l’opinion publique, mais aussi du monde agricole, il a été mis en place en France le Plan Ecophyto…

Estudio de los mecanismos de resistencia a glifosato en dos biotipos de lolium spp.

The aim of this study was to analyse the glyphosate resistance mechanisms in Lolium multiflorum and Lolium rigidum. Both these species were collected in Spain, the former in Andalusia in olive grove crops and the latter in citrus plantations in Valencia. These were compared to a susceptible population of both species, which had never been treated with herbicides. Absorption-translocation, contact angle and retention assays were performed. The experiment design used was completely random with six replications. The study was performed as a consequence of data previously obtained for screening and dose-response trials, and which served to confirm the resistance of the resistant biotypes. Regar…

Behaviour of alkyl oleates following foliar application in relation to their influence on the penetration of phenmedipham and quizalofop-P-ethyl

Summary The foliar penetration of four alkyl oleates (methyl to butyl) and their influence on the penetration of phenmedipham and quizalofop-P-ethyl was studied in barley (Hordeum vulgare L.), cleavers (Galium aparine L.) and pea (Pisum sativum L.). Loss of alkyl oleates from glass and plant surfaces was inversely related to the length of the alkyl chains and was assumed to be due to volatilization. All four alkyl oleates after application alone, readily penetrated into pea and barley leaves but much less into G. aparine. Penetration of methyl oleate appeared to be faster than that of butyl oleate. Both alkyl oleates were completely metabolized in barley and pea in 27 h, but not in G. apari…

Seed oils as additives: penetration of triolein, methyloleate and diclofop-methyl in maize leaves

Summary: Resume: Zusammenfassung Methyl ester derivatives of seed oils have a greater effect on graminicide efficacy than the parent oils. To explain this difference, we investigated the penetration of the radiolabelled oils, triolein (TRI) and methyl oleate (MEO), in maize leaves, and their influence on diclofop-methyl penetration. Over a period of 3 h 30% of applied TRI penetrated maize leaves, but no further penetration was observed. In contrast, MEO entry proceeded regularly to 72% over a period of 27 h. The amount of oil found in epicuticular wax (chloroform wash) was generally less than 4% of the recovered label, and was even lower (<1%) in ‘glossy 1’ hybrids which have no crystalline…

From weedkillers to environmentally begnin herbicides: history of chemical weeding from 1944 to 2011 in France

International audience

Response and effect traits of arable weeds in agro-ecosystems: a review of current knowledge.

25 pages; International audience; Integrating principles of ecological intensification into weed management strategies requires an understanding of the many relationships among weeds, crops and other organisms of agro-ecosystems in a changing context. Extensively used during the last two decades in weed science, trait-based approaches have provided general insights into weed community response to agricultural practices, and recently to understanding the effect of weeds on agro-ecosystem functioning. In this review, we provide a holistic synthesis of the current knowledge on weed response and effect functional traits. Based on the literature and recent advances in weed science, we review cur…