Journal of Research in Weed Science

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.

Abstract Compare other countries studies associated with field bindweed (Convolvulus arvensis L.) biological control is too short in Iran. Field bindweed is a major weed of several field crops. During a survey, we focus to finding natural enemies of this weed in Khorasan Razavi province for two years. This paper reports the presence of a seed beetle Spermophagus sericeus Geoffroy as a major natural enemy against field bindweed (Convolvulus arvensis L.) in northeast of Iran. Samples of field bindweeds capsules and seeds collected in tomato fields at two locations in that region. Results showed that the reproductive organs of field bindweed were severely damaged, where 76 and 62 percent of capsules and seeds were infested by S. sericeus respectively. Our findings showed the high level control of field bindweed by S. sericeus and this beetle can be considered as a proper bio control agent for this weed in Iran. However more studies about host specificity of this beetle should be performed.