Introduction: Pendimethalin is an herbicide that is used worldwide to attack certain wide leaf and grassy weeds in a variety of agricultural and non-crop regions, with a claimed very low toxicity to human. There have been some few reported cases of acute Pendimethalin toxicity to date, around the world. We report a case of Pendimethalin toxicity resembling and managed initially as organophosphorus poisoning. Case Description: A 42-year-old agricultural worker was found unresponsive in his field with profuse oral secretions. The patient presented with altered mental status, where Glasgow comma scale was 10, oxygen saturation at room air was 88 %, Blood pressure measured 125/75, pulse rate was 95 beats per minute, and temperature was 37 °C. The patient’s pupils were constricted, equal, regular, and reactive. Chest examination revealed scattered respiratory crepitations. The patient also had a distinct garlic odor very similar to that of Organophosphate compounds. The results of his laboratory investigations revealed only hypoxemia. The patient received atropine and supportive management, which prompted the chest secretions to clear up and allow him to restore consciousness without experiencing any neurological problems. Conclusion: Pendimethalin toxicity can present with manifestations mimicking acute organophosphorus poisoning. Proper supportive care is needed for the management of acute Pendimethalin toxicity.

Background and Objectives Nowadays, herbicides are crucial for modern agricultural systems. Yet, improper application of herbicides will have dangerous consequences. For example, there will be crop damage due to long lasting herbicide residue or herbicide drift on neighbor crops if applied on non-target species. The purpose of this experiment was to determine the sensitivity of wheat and barley to Pendimethalin residue by using bioassay. Materials and Methods In order to evaluate soil residue of Pendimethalin, experiments with completely randomized designs were carried out in the greenhouse at Faculty of Agricluture and Natural Resources of Gonbad Kavous University. In this experiments, different doses of Pendimethalin (0, 1, 5, 10, 15, 20, 30, 40, 50, 75 and 100 % of recommended dose) were applied on wheat and barley in order to measure the dry weight of root and shoot of crops. The concentration of herbicides was made by dilution of stock solvent. Three/four-parameter log-logistic curves were used for fitness of the data. Results Results indicated that almost all data followed the three-parameter logarithm logistic curve. Results of separate fitness of data showed that the residue of Pendimethalin always caused reduction of dry weight of the evaluated crops. Fifty percent reduction of shoot dry weight of wheat and barley was obtained from 400. 5 and 623. 05 g. a. i. ha-1 of Pendimethalin and the ED50 values of root dry weight of wheat and barley were 65. 88 and 269. 66 g. a. i. ha-1 of Pendimethalin, respectively. Discussion Generally, the results of simultaneously fitted data shows that wheat is always more sensitive to Pendimethalin rather than barley. Based on results, even the very little portion of herbicides can cause damage to crops, thus, considering the sensitive crop in rotation is so important since this residue can stay active even in two-season crops and make crop injuries. The selection between 3 and 4 Logarithm logistic model was based on: 1. Lack of fit test significance 2. Significance of estimated parameters, especially the parameters and the way of distribution of data around the curve (graphical observation).

Introduction: Soybean is one the strategic crops which contributes to provide a part of food in 43 countries. Soybean planting area and production in the world are 102 million hectare and 261 million tonnes respectively. Its planting area was 764000 ha in Iran in 2013. Mazandaran, Guilan and Golestan are the most soybean producing province in Iran. Golestan with 53405 ha and 90000 tonnes production is the first soybean producer in Iran. Weed competition is considered one of the most important inhibitor factors, which not only causes yield losses but also, reduction in quality by interference in soybean growth and development. Yield reduction by weeds was reported by 28% under the Caspian Sea climate. Mean yield loss for one plant/square meter, has been reported up to 30% and it may reach to 80% in higher weed density. Therefore study of soybean weed control is avoidable. Materials and Methods: In order to control weeds in soybean fields, an experiment was conducted as Randomized Complete Block Design (RCBD) with three replications in Gorgan agricultural research stations in a field that had enough weed infection. The treatments were triflutalin (treflan 48% EC) 2. 5 l/ha, metribuzin (sencor 70 % wp) 0. 5 l/ha, metribuzin 0. 5 l/ha+ trifluralin 2. 5 l/ha, imazethapyr (persuite 10% SL) 0. 6 l/ha, imazethapyr 0. 8 l/ha as pre plant, oxyfluorfen (goal 24% EC)0. 75 l/ha, Pendimethalin (stomp 33% EC) 3 l/ha, imazethapyr 0. 6 l/ha, imazethapyr 0. 8 l/ha, metribuzin 0. 3+ imazethapyr 0. 6 l/ha, Pendimethalin 2. 5 l/ha + imazethapyr 0. 6 l/ha as pre-emergence, oxyfluorfen 0. 5 l/ha, bentazon (basagran 48% SL) 1. 5 l/ha, imazethapyr 0. 6 l/ha, imazethapyr 0. 8 l/ha, bentazon+ imazethapyr 0. 6 l/ha, cletodim (select super 12% EC) 1l/ha + imazethapyr 0. 6 l/ha as post-emergence at 4-6 leaf stage and weed free treatment as a control. Plot size was 1. 4m×10m. Seed rate, row spacing, cultivar and other cultivation method was done by conventional method. Each plot was divided to two parts, which one part was treated by herbicides and the other part was held untreated and considered as control treatment. In weed free check treatments, weeding was done with 10 days interval but in weedy check no weeding and no chemical weed control was done. To investigate the effect of treatments on weed number, weed fresh and dry weight, a quadrate of 0. 5 × 0. 5 m was fixed in each plot (so that it represents the weeds of whole plot). Before harvesting, all of the emerged weed species in fixed quadrates were identified, counted and their dry weight was measured after drying in 75 celcius degree oven for 72 hours. At harvest 5 plants per plot were randomly selected and yield components were measured. For yield, two 0. 5 m2 quadrates were harvested in each plot and grain yield and biomass were determined. Qualitative evaluation of soybean, which includes chlorosis and necrosis in leaves, was done based on EWRC standard method. Data analysis of variance was performed using SAS software version 9. 1 and the means were compared using LSD test at 5% level. Since field data were not normal, a logarithmic and root square (√, (x+0. 5)) transformation was used to normalize data. Results: The results showed that all treatments caused reduction in weed number percentage than control treatment. The highest reduction was observed in imazethapyr 0. 8 l/ha (pre plant) at par with hand weeding treatment. Pendimethalin 2. 5 l/ha + imazethapyr 0. 6 l/ha, metribuzin 0. 3+ imazethapyr 0. 6 l/ha as pre emergence had the next rank. The highest yield after hand weeding was obtained in imazethapyr 0. 8 l/ha (pre plant) followed by Pendimethalin 2. 5 l/ha + imazethapyr 0. 6 l/ha and imazethapyr 0. 8 l/ha as pre emergence. Therefore based on the results of this study using of imazethapyr 0. 8 l/ha as pre plant or pre emergence are recommended for weed control in soybean fields and mixing of this herbicide with Pendimethalin is also conducive to increasing the herbicide spectrum. Application of this herbicide (imazethapyr 0. 8 l/ha) at 4-6 leaf stage of weeds, to obtain higher yield is possible too. The results of this experiment showed that some of post-emergence herbicides caused a little phytotoxicity on soybean (oxifluorfen 0. 5 liters / ha (20%), Bazagaran + Persoite (15%), Coltodium + Persoite (10%), Bazagaran (5 to 10%), Persuite 0. 8 liters per hectare (lower than 5%)). It should be noted that the phytotoxicity of all treatments was eliminated in the later stages of growth.

In order to study the effect of Pendimethalin (Prowl) on weed control of onion (Allium cepa L. ) fields, an experiment has been carried out in randomized complete block design with four replications, during 2017 in Agricultural Research Center of South Kerman. The treatments include application of Pendimethalin (Prowl) at 3. 5, 3, 2. 5, 2 L ha-1 (pre-emergence), oxyfluorfen (Goal) at 750 ml ha-1, and its repetition 18 days later (postemergence), oxadiazon (Ronestar) at 3 L ha-1 (per-emergence), oxadiazon at 2 L ha-1 (post-emergence), ioxynil (Totril) at 3 L ha-1 (post-emergence) plus removing narrow leaves weeds by hand, and weed free as control. The highest relative abundance of weed species has been Bromus tectorum L., Malva parviflor L., Chenopodium murale L., Anagallis arvensis L, and Rumex crispus L. at 39%, 17%. 12%, 9%, and 8%, respectively. Results show that herbicide treatments have had a significant effect on weed density and biomass. Applications of Pendimethalin at 3. 5 L ha-1 reduces biomass of A. arvensis, R. crispus, M. parviflor, B. tectorum, C. murale, and total weed by 100%, 92%, 91%, 82%, 77%, and 79%, respectively. Onion yield has been 59. 95 ton ha-1, increased by 138% when Pendimethalin is applied at 3. 5 L ha-1. Therefore, Applications of Pendimethalin at 3. 5 L ha-1 is recommended in onion fields because of optimum weed control efficiency and increasing yield.

Background and objectives: Chemical weed control is one of the most common weed control methods in potato field in the world and Iran. Herbicides which are using for potato fields include: Metribuzin, Paraquat, Pendimethalin, Rimsulfuron, EPTC, Solfosulfuron, Ethalfluralin, Trifloralin, Pendimethalin, Prosulfocarp, Metolachlor, and Oxadiargyl. In Iran, Metribuzin and Paraquat are recommended herbicides in potato field. Due to the limited number of herbicides registered, application time, number and variety of site, the objective of our research was to evaluate the efficacy of Ethalfluralin, Pendimethalin and Trifluralin for weed control and yield and component yield of potato. Materials and methods: Trials were conducted in Ardabil Agriculture and Natural Resources Research Station in 2013. The experiment performed as does-response based on Randomized Complete Block Design with three replications and potato, s cultivar was Agria (common cultivar in Ardabil). Herbicides studied were Trifluralin (Treflan EC 48%) at 0. 125, 0. 25, 0. 5, 1, 2 and 4 L/ ha, Etalfluralin (Sonalan EC 33%) at 0. 125, 0. 25, 0. 5, 1, 2 and 4 L/ ha and Pendimethalin (Stomp EC 33%) at 0. 25, 0. 5, 1, 2, 4 and 6 L/ ha; also two treatment (with and without weeding) was considered as control. The weed sampling carried out at 20 and 60 days after treatment. Results: Results showed that maximum reduction percent of total weed biomass at 20 days after treatment achieved by 4, 6 and 4 L/ha Ethalfluralin, Pendimethalin and Trifluralin, respectivelly and application 6, 4 and 4 Pendimethalin, Ethalfluralin and Trifluralin reduced more than 82 % at 60 days after treatment, respectivelly. The best treatment of reduction percentage of common lambsqurters biomass was 6 L/ ha Pendimethalin at 20 and 60 days after treatment that had not significant difference by 4, 4, 4 L/ha Ethalfluralin, Trifluralin and Pendimethalin, respectivelly. The maximum reduction percentage of redroot pigweed biomass was 4 L/ha Ethalfluralin. This treatment could reduce redroot pigweed biomass 97 and 91%, respectivelly. After weed free treatment the best treatment of yield per plant and total tuber yield was 4 L/ha Pendimethalin that cause to increase more than two fold. Conclusion: This study showed application 6 and 4 L/ ha Pendimethalin and Ethalfluralin created maximum reduction percentage of weed biomass at 20 and 60 days after treatment. Application 4 L/ ha Pendimethalin increased yield per plant and total tuber yield of potato more than two fold. Therefore, the use of Pendimethalin and Ethalfluralin herbicides is recommended for potato weed control and increasing potato yield.