Journal of Research in Weed Science

Abstract Striga hermonthica is widespread in several regions of Burkina Faso. It attacks crops of agronomic interest, causing losses ranging from 20 to 100% of grain yield in sorghum varieties. This study carried out at the weed science laboratory from October 2022 to February 2023 aims to identify sorghum varieties resistant to Striga hermonthica and local plants that inhibit or stimulate its germination. Fifteen varieties of sorghum has been evaluated for their germination stimulant capacity production using the agar gel method. The roots of two seedlings of each variety were buried in the opposite position in the agar medium containing Striga seeds. The effect of nine local plants on Striga hermonthica seeds germination has been evaluated by preparing 10% aqueous extract for each plant by macerating a mass of 10 g of powder in 100 ml of sterile distilled water. The inhibitory effect was estimated by conditioning the Striga hermonthica seeds during 14 days in each of the plant aqueous extracts and the stimulatory effect by the application of aqueous extracts on the Striga hermonthica seeds. The results revealed Rsoe 38 (MGD=0.74cm), Icsv 1049 (MGD = 0.74cm), Ouédzouré (MGD = 0.81cm), Grinkan (MGD = 0.85cm), Rsoe 15(MGD = 0.85cm) and B 35 (MGD = 0.97cm) as resistant to Striga hermonthica germination. Parkia biglobosa and Tephrosia purpurea have proved effective in inhibition while Andira inermis and Albizia zygia stimulate it. The promotion of resistant sorghum varieties and plants with inhibitory or stimulatory effects could be an important asset for the biological control of Striga hermonthica in the most infested areas.

Abstract This study was designed to assess the effect of rimsulfuron soil residues (0, 0.11, 0.58, 1.1, 2.4, 3.6 and 5.8 μg a.i. kg−1soil) on sugar beet (Beta vulgaris L.) plant with bioassay method. Plant response of roots and shoot dry weight per pot were described by A log-logistic model using R software as a function of rimsulfuron doses logarithm by non-linear regression and used to calculate the doses for 10, 50 and 90% inhibition of plant root and shoot dry weight (ED10, ED50 and ED90). Sugar beet was susceptible to rimsulfuron soil residues in all concentrations and biomass loses increased linearly as the concentration of rimsulfuron increased in the soil up to 0.11 µg/kg soil. The root biomass was more sensitive than shoot biomass where the ED50 calculated for root and shoot biomass was 0.123 and 0.202 µg. kg-1 soil, respectively. The same results were obtained for ED10 and ED90. From the results of the study, it is concluded that sugar beet is very sensitive and suitable species for using as a bio indicator in bioassay experiments for determine the side-effects of rimsulfuron at low concentration rates. By determining the concentration of rimsulfuron soil residues and the side-effect on sensitive crops, the agricultural managers could have some flexibility in crop rotations program if sensitive crop such as sugar beet is to be planted in the field that previously treated with sulfonylurea herbicides.