Journal of Research in Weed Science
Volume:1 Issue: 1, Sep 2018

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.

The use of cover crops can be considered as an effective method in sustainable agriculture through reducing herbicide use, improving soil and increasing crop yield. An experiment was conducted using randomized complete block design with three replications in Agricultural and natural resources research center of Ardabil (Moghan) in 2015-2016. Cover crops was considered as the main factor (mixed wheat + crimson clover, monoculture wheat and mixed (rye + wheat)) and mulch management as subplots and control (no cover crop use post-emergence herbicide Maister (Foramsulfuron + Idosulfuron 3.1% OD)). The results showed no significant difference between treatments in terms biomass production, the lowest weed biomass was related mixed of rye + wheat in both crop management methods. In wheat and wheat+ rye a significant decrease was observed in crop yield components possibly due to the release of allelopathic materials and soil properties, But the crimson clover mix of wheat + maize yield satisfactory beside weed control a good yield was obtained after the treatment with herbicide. The results showed that the effect of cover crop, crop management and their interaction except grain weight, were significant for ear dry weight, biological yield, number of rows per ear and number of kernels per ear. The highest values of grain yield, ear dry weight, biological yield, number of grains per ear was achieved in treatments clover + wheat and the least amount of yield and yield components of treated wheat was obtained in residues removed management.

Bentazon herbicide is a post-emergent herbicide and a photosynthesis inhibitor in broadleaf weed. However, different parameters of Bean Kautsky curve changed significantly. Seeds were treated magnetically at three levels normal, 100 mT and 150 mT (3 hours) and weed control (weeding (by hand), weed free (untreated), control by 25 percent herbicide, or 0.6 l.ha-1, 50 percent herbicide or 1.2 l.ha-1, and 100 percent herbicide or 2.5 l.ha-1. Due to the major paramagnetic components of bean seeds, affected the parameter minimum quantum yield of PS Π (Fv/Fm) significantly (p<0/01) as in the treatment of magnetic field 150 mT and 2.5 l.ha-1 herbicide decreased significantly (0.61) although Bentazon is a selective herbicide of bean. However, besides posing damage to photo-oxidation and center PS Π, 150 mT magnetic fields lengthened the time to reach maximum fluorescence (493.3) and maximized the stress to the parameter Fo and Fo/Fm. In the case that no herbicide was applied, it amounted to the maximum fluorescence at the least time (183.3). Also, in the absence of herbicides (both weeding and weed free), basic quantum efficiency were always normal (0.14 to 0.21); however, by using the herbicides, it exceeded its normal range. Therefore, the selective of the herbicide did not mean the immunity of the plant against the herbicide completely. In general, 100 mT magnetic fields were known to be an effective treatment for plant’s exposure to Bentazon herbicides and stronger field had the opposite effect.

In modern agriculture, use of herbicides has become indispensable for managing weeds in cultivated lands, due to the scarcity of labors in almost all parts of the globe. Herbicides provide effective weed control in agriculture, yet their continuous and excessive use may pose serious health and environment threats. Pendimethalin is proved to be a very effective pre-emergence herbicide for the control of annual weeds in leguminous and other vegetable crops. Therefore bio-efficacy and residues of pendimethalin were determined in chickpea (Cicer arietinum L.) crop at farmers’ field. Pendimethalin was applied at 796 g ha-1 as a pre-emergence herbicide to control weeds in chickpea fields. Pendimethalin was found effective against weeds viz. Vicia sativa, Convolvulus arvensis, Chenopodium album, and Lathyrus sativa. Terminal residues of pendimethalin were found below

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.

The survey was conducted in the farmers’ field of Durba Chara village of Gauripur upazilla under Mymensingh district to find out the floristic composition of weeds in three crops i.e. summer rice, potato and winter rice under T. aman-potato-boro cropping pattern. Five farmers’ fields were surveyed by using a quadrat of 0.5m × 0.5m size in four spots from each field randomly. The data were summarized using frequency, field uniformity, mean field density and relative abundance. A total of 27 weed species belonging to 11 families were found in T. aman, potato and boro rice, of which 22 species were under 11 families in T. aman, 15 species under seven families in potato and 20 species were under nine families in boro rice. Echinochloa crusgalli was the most abundant weed in both potato and boro rice while in T. aman, Ludwigia hyssopifolia dominated over others. Echinochloa crusgalli and Polygonum hydropiper were common in both potato and boro rice. The other three dominant weed species i.e. Cyperus rotundus, Cynodon dactylon and Panicum distichum in potato and Eclipta alba, Cyperus difformis, Eleocharis atroperpurea in boro were completely different from each other. In T. aman, five completely different weed species i.e. Ludwigia hyssopifolia, Alternanthera sessilis, Polygonum orientale, Fimbristylis miliaceae and Hedyotis corymbosa were found dominant. Broadleaf weeds were dominant in both T. aman and boro but in potato, grasses dominated over others.