Field experiments were conducted to study the phenology and growth of broadbean (Vicia fabaL. ‘Alameda’) and crenate broomrape (Orobanche crenataForsk. # ORACR) in relation to planting date. The establishment of crenate broomrape on broadbean planted between mid-December and mid-January coincided with the flower initiation on the crop. Establishment occurred during the vegetative phase, several weeks before flowering from a mid-November and mid-October planting. In general, no consistent relationships were observed between growth of the host and attachment or subsequent growth stage of the parasite. The maximum number of crenate broomrape plants successfully attached to the host as well as the duration of the underground stage of crenate broomrape decreased as broadbean planting was delayed. Broadbean dry weight decreased as infection rate increased. This effect was more intense in early than late plantings.

Summary The influence of broomrape (Orobanche crenata Forsk) infection levels on commercial broad bean (Vicia faba L.) crops was investigated and an equation relating yield losses to O. crenata density was derived. O. crenata growth was weakly and negatively related to the final height or shoot number of the broad bean plant. O. crenata decreased seed yield mainly by reducing the number of pods. The number of seeds per pod was also decreased by O. crenata infection when competition occurred at late‐crop growth stages when most of the pods had already developed. Bean unit seed weight was only weakly affected by infection. Correlation coefficients between O. crenata number and broad‐bean seed yield per plant were significant at P=0·05 and greater than 0·70 in most locations. On average, about four O. crenata per broad‐bean plant decreased seed yield by half. An estimation of the percentage of losses in any field can be calculated from the equation: %loss = 100 × 0·124 × OcN. where OcN is the average final number of emerged O. crenata per plant.

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Summary The broomrape (Orobanche crenata Forsk) susceptibility to glyphosate applied on faba‐bean (Vicia faba L.) as affected by the parasite growth stages at the time of application was studied under field conditions. Glyphosate treatments delayed O. crenata emergence. Single glyphosate application to faba‐bean infected with O. crenata predominantly at the stage (a) (small nodule) and (b) (nodules with initial vestigial roots) resulted in a moderate to low control. When the stages (c) (shoot bud already visible) or (d) (shoot and vestigial roots well developed) were the predominant stages, an excellent control was achieved with a single glyphosate application at 60 g ha−1. Increased development stages, with the shoot emerged from the shoot bud, decreased its susceptibility to glyphosate. La lutte contre Orobanche crenata en culture de férerole avec le glyphosate; influence des doses d'herbicide et du stade de développement du parasite

Absorption and translocation of '"C-glyphosate was evaluated under controlled conditions in peas (Pisum sativum L.) and broad beans (Viciafaba L.) parasitised or not by crenate broomrape Orobanche crenata Forsk.), Absorption increased with time up to 12 days after treatment, and reached about 50% of the '"C-glyphosate applied. Three days after treatment 70-85% of the total herbicide absorbed had been translocated out of the treated leaflet. There was no consistent difference in absorption and translocation between infected and non-infected plants 12 days after treatment. The '^C-glyphosate concentration in the root system increased with time in broad beans. In peas it remained more or less constant from 3 days after treatment. Generally, pods were stronger sinks for glyphosate than other parts of the plant. Herbicide accumulation in broomrape increased with its growth stage, and the parasite was a much stronger sink for glyphosate than the legume root system.A. Arjona-Berral. J. Mesa-Garcia and L. Garcia-Torres blieb sie nach 3 Tagen nach der Behandlung mehr Oder weniger konstant. In die Hulsen wurde im allgemeinen mehr Glyphosat verlagert als in andere Teile der PHanzen. In der Orobanche nahm die Akkumulation des Herbizids mit dem Wuchsstadium zu und war viel groBer als im Wurzelsystem der Gemusepflanzen.