<p>Herbicide resistance poses a threat to sustainable vegetation management. Recently, the first report of 2,4-D resistance in buckhorn plantain (<i>Plantago lanceolata</i> L.) as well as the first report of 2,4-D resistance in turf was published. Additional 2,4-D resistant buckhorn plantain ecotypes have been reported in Indiana, Ohio, Pennsylvania, Georgia, and Virginia in the short time since. Thus, the aims of this research were to investigate the mechanism(s) of 2,4-D resistance in a resistant ecotype of buckhorn plantain, screen other potentially resistant ecotypes and measure them for fitness penalties, and identify effective turfgrass cultural control practices for managing buckhorn plantain. </p><p><br></p><p>A radiolabeled 2,4-D experiment was conducted to investigate absorption and translocation, and a 2,4-D dose-response experiment was conducted using malathion as a cytochrome P450 inhibitor to assess the potential mechanism of 2,4-D resistance in buckhorn plantain. The clearest difference between the resistant (IN-GW) and susceptible ecotype (IN-WL) was the interaction between ecotype and harvest period for [¹⁴C]2,4-D in the non-treated shoots. After 192 hr, the susceptible ecotype had a higher amount of [¹⁴C]2,4-D in the non-treated shoots (16.1%) than the resistant ecotype at any of the harvest periods (5.5-7.3%); the amount of [¹⁴C]2,4-D in the non-treated shoots was similar across all three harvest periods for the resistant ecotype. Thus, reduced translocation plays an apparent role in 2,4-D resistance in buckhorn plantain. Malathion pre-treatment did not fully revert the resistant ecotype back to susceptible. Thus, if cytochrome P450 metabolism is part of the 2,4-D resistance mechanism of this buckhorn plantain ecotype, it is likely a contributor and not the sole mechanism of resistance. </p><p><br></p><p>In total, this research identified four 2,4-D resistant buckhorn plantain ecotypes from Indiana and one from Ohio. Only one report of a failure to control buckhorn plantain was confirmed to be a susceptible ecotype. When compared to susceptible ecotypes in a garden study, no major fitness penalties were identified in resistant ecotypes. </p><p><br></p><p>Given that no specific cultural or biological control methods of buckhorn plantain have been recognized to date, two field trials were conducted to investigate the influence of 1) mowing height and nitrogen rate on buckhorn plantain coverage and 2) mowing frequency on buckhorn plantain coverage and seed production. Nitrogen fertilization and low mowing reduced buckhorn plantain coverage after 3 yr, but low mowing also increased crabgrass and dandelion as well as reduced turf quality. Frequent mowing reduced viable seed production, but that did not translate into a reduction in buckhorn plantain coverage after 2 yr. </p><p><br></p><p>This research demonstrates the complex mechanism of action of 2,4-D, as the resistance mechanism for buckhorn plantain was not fully elucidated. It also highlights the importance of utilizing best management practices for managing weeds in turf, including rotating herbicide chemistries, high and frequent mowing, and nitrogen fertilization.</p>

This thesis deals with grasslands, distribution, husbandry, nutrition and treatment. Furthermore, the botanical composition of grasslands and the most important species of weeds, application of N fixation of legumes and plants. In another part of the description and application of dicotyledonous herbs and their economic importance. Furthermore, determination and maintenance of the water system at the sites, and nutrition and fertilization dicotyledonous herbs and vegetation preservation and storage of forage. A key goal of this work is the plantain (Plantago lanceolata L.), its ecology and involvement in different vegetation types. A separate chapter is devoted to the description of the biology, pollination, phenology and agro ? technical cultivation of plantain. The last chapter describes the use of the drug substance and plantain in pharmacy. In the second part of the work to illustrate knowledge of the occurrence of Plantago lanceolata supplemented by results of our own observations (tables and graphs) showing the involvement of P. lanceolata in different types of grassland and two-year follow-up period.

La banane plantain (Musa paradisiaca) est l’aliment de base de millions de personnes dans le monde et sa culture génère des revenus permanents pour un grand nombre d’agriculteurs, dans des plantations de taille petite ou moyenne. Comme dans d’autres régions tropicales, la culture du plantain en Guadeloupe et en Haïti est soumise à de fortes contraintes parasitaires aussi bien telluriques (i.e. du sol : nématodes phytoparasites et charançon du bananier) qu’aériennes (Cercosporiose noire notamment). Les moyens de lutte conventionnels reposent sur l’usage de produits de synthèse dont les effets néfastes sur l’environnement (sols, eaux, animaux) comme sur la santé humaine ne sont plus supportables. Il est donc urgent de réfléchir à des solutions agro-écologiques permettant de rétablir les équilibres biologiques, de maintenir une bonne qualité des sols et une production optimale dans les systèmes de culture plantains. C’est le but de ce travail de thèse qui couple la réalisation d’un diagnostic agro-écologique dans des parcelles paysannes, et le test d’alternatives agro-écologiques en milieu semi-contrôlé. Pour ce faire, une typologie des systèmes de culture plantains a été réalisée à l’issue d’une enquête agro-environnementale dans les deux zones d’étude. Elle a permis de sélectionner 23 parcelles en Guadeloupe et 12 en Haïti dans lesquelles un diagnostic agro-écologique a été conduit. Sur la base de ce diagnostic et de la recherche d’alternatives agro-écologiques à l’usage des produits chimiques, une expérimentation au champ a été mise en place en Guadeloupe en station de recherche, permettant le test de trois pratiques culturales innovantes pour le plantain (seules et combinées), à savoir : i) l’introduction d’une plante de service Paspalum notatum pour la gestion des adventices et la réduction de l’utilisation d’herbicides ; ii) l’apport de vermicompost pour le contrôle des nématodes phytoparasites inféodés au bananier plantain et la fertilisation de celui-ci ; iii) l’utilisation de plants sains PIF (Plants Issus de Fragments de tiges) indemnes de nématodes et de larves de charançon du bananier. La typologie des systèmes de culture plantains révèle que : i) en Guadeloupe les précédents : jachère, ananas et banane plantain sont prédominants avec un niveau d’intensification faible (apports d’intrants chimiques faibles et peu fréquents) ou élevé (apports d’intrants chimiques élevés et plus fréquents) ; ii) en Haïti, les précédents : jachère, banane plantain et manioc prédominent avec un niveau d’intensification faible ou nul (apport d’intrants inexistant). Les résultats du diagnostic agro-écologique montrent que, i) lorsque le niveau d’intensification est faible, les bananeraies plantains pérennes et le précédent-ananas permettent de maintenir une bonne qualité du sol et une bonne régulation des parasites telluriques ; ii) lorsque le niveau d’intensification est fort, les populations d’ingénieurs du sol diminuent drastiquement, alors que le cortège parasitaire tellurique augmente sans que cela n’affecte l’obtention de bons niveaux de rendement instantannés (parcelles précédées d’ananas ou d’une jachère principalement) ; iii) en absence totale de fertilisation, il résulte une diminution de l’activité biologique du sol mais aussi du rendement du plantain, exacerbé par le choix des précédents-culturaux (manioc ou banane plantain) en lien avec les contraintes pédoclimatiques et la maladie des raies noires (Cercosporiose noire) causée par Mycosphaerella fijiensis, notamment au sein des parcelles Haïtiennes ; iv) la succession plantain/plantain est la plus pénalisante vis-à-vis de la culture du plantain, car quelque soit le niveau d’intensification, le rendement reste relativement faible, en lien avec une dégradation de l’état sanitaire, comparativement aux autres précédents. / Plantain (Musa paradisiaca) is the staple food of millions of people worldwide and its cropping generates ongoing revenues for many farmers who are planting small or medium size areas. As in other tropical regions, plantain cultivation in Guadeloupe and Haiti is under heavy parasitic constraints terrestrial (plant-parasitic nematodes and banana weevil) as well as aerial (black Sigatoka in particular). Conventional means of control based on the use of synthetic products which adverse effects on the environment (soil, water, animals ...) as on human health are not bearable any more. It is thus urgent to think about agroecological solutions allowing to restore the biological balances, to maintain good soil quality and optimal plantain cropping systems.This is the ultimate goal of this thesis which couples the realization of an agroecological diagnosis in peasants’ plots, and the test of agroecological alternatives in semi-controlled conditions. To do this, a typology of plantain cropping systems was carried out from an agrienvironmental survey in the two study areas. It allowed to select 23 plots in Guadeloupe and 12 in Haiti in which an agroecological diagnosis was implemented. Based on this diagnosis and the research of agroecological alternatives to the use of chemicals, a field experiment was set up in Guadeloupe, in an experimental station allowing the test of three innovative practices for plantain cultivation (alone and combined), namely : i) the introduction of a cover-crop Paspalum notatum for weed control while reducing the use of herbicides ; ii) the input of worms’ compost to control plant-parasitic nematodes specific to plantain and to fertilize it ; iii) the use of healthy “PIF” plants (plants issued from stem fragments) free from telluric pests (nematodes and weevil’s larvaes).The typology of plantains cropping systems shows: i) in Guadeloupe the previous crops are: fallow pineapple and plantain predominate with a low level of intensification (low and infrequent chemical inputs) or high (high and frequent chemical inputs); ii) in Haiti, the previous crops are: fallow, plantain and cassava predominate with a low level or no intensification at all (no inputs). The results of the agroecological analysis show that : i) when the level of intensification is low, perennial plantain and pineapple as previous crops help maintaining a good soil quality and a good regulation of the telluric pests ; ii) when the level of intensification is strong, the soil engineers drastically reduce, while the density of telluric parasites increases without affecting good levels of instantaneous yields (plots where the previous crop is pineapple or mostly fallow) ; iii) when the fertilization is totally missing, it decreases the biological activity of the soil furthermore the plantain yields, exacerbated by the choice of the previous crop (cassava or plantain), in connection with soils and climate constraints and the black Sigatoka caused by Mycosphaerella fijiensis, especially in the Haitian plots ; iv) the crop succession plantain/plantain is the most critical regarding the plantain’s cropping, because whatever the level of intensification, the yields remain relatively low in connection with a degradation of the health state, compared to other previous crops.The driving of an experiment in a research station shows that on the scale of one year, the three tested innovative practices allow maintaining a good soils quality. Healthy plants "PIF" have a better health state (absence of plant parasitic nematodes in the roots) which helps a significant increase of the yields. Cover-crop P. notatum helps the weeds and the soil pests control and favors the improvement of soil biological activity and plantain yields. Worms’ compost contributes to the maintenance of a better soils quality while allowing the regulation of the populations of plant-parasitic nematodes of the plantains.