fa ارزیابی کارایی برخی از علف کش های جدید و رایج در کنترل علف های هرز ذرت عمومى General پژوهشي Research <div style="text-align: justify;"><span dir="RTL" lang="AR-SA" style="font-size:12.0pt"><span arabic="" style="font-family:" traditional="">به منظور ارزیابی کارایی برخی از علف کش های جدید و رایج بر کنترل علف‌های هرز پهن‌برگ یک‌ساله، آزمایشی در سال زراعی 1402 در قالب طرح بلوک کامل تصادفی با 11 تیمار در 4 تکرار در مزارع تحقیقاتی استان اردبیل، البرز و کرمانشاه انجام گرفت. تیمارها شامل 1، 2، 3، 4 و 5- علف‌کش تیفن سولفورون- متیل (کالیپسو WG%75) 20، 24، 28، 32 و 36 گرم در هکتار به‌صورت پیش‌رویشی، 6- علف‌کش بنتازون + ام‌ث‌پ‌آ (بازاگران&nbsp; ام 60 SL%46) 2 لیتر در هکتار به‌صورت پس‌رویشی، 7- علف‌کش تربوتیلازین (امیزینگ SC%50) 1/8 لیتر در هکتار به‌صورت پیش‌رویشی، 8- علف‌کش تربوتیلازین (SC%50) 1/8 لیتر در هکتار به‌صورت پس‌رویشی، 9- علف‌کش توفوردی + ام‌ث‌پ‌آ (یو46 کمبی فلوئید SL%67.5) 1/5 لیتر در هکتار به‌صورت پس‌رویشی، 10- علف‌کش بروموکسینیل + ام‌ث‌پ‌آ (برومایسید ام آ EC%40) 1/5 لیتر در هکتار به‌صورت پس‌رویشی، 11- شاهد (وجین تمام‌فصل) و 12- شاهد (بدون مدیریت) بودند. نتایج نشان داد در همه مناطق مورد بررسی، کارایی علف‌کش‌های ثبت شده برومایسید ام‌آ و امیزینگ به‌صورت پیش‌رویشی در کنترل تاج‌خروس‌وحشی (Amaranthus retroflexus L.)، سلمه تره (.Chenopodium album L) و تاج‌خروس‌‌خوابیده (Amaranthus belitoides S. Watson) مطلوب و به ترتیب بیش از 85 و 80 درصد بود. توق (.Xanthium strumarium L) و عروسک‌پشت‌پرده (.physalis divaricata L) با برومایسید ام‌آ بیش از 90 درصد در کرمانشاه کنترل شدند و گاوپنبه با کاربرد علف‌کش پیش رویشی امیزینگ و همچنین مقادیر 32 و 36 گرم در هکتار کالیپسو در مغان حدود 75 درصد کنترل شدند. همه علف‌کش‌های مصرف شده بجز تیمارهای 20 تا 36 گرم در هکتار کالیپسو در کرج و کرمانشاه، سبب افزایش حدود 13/5 تا 40 درصدی عملکرد دانه ذرت نسبت به شاهد (بدون مدیریت) شدند. درکل مقادیر پیشنهادی علف‌کش کالیپسو (20 تا 32 گرم در هکتار) نسبت به برخی علف‌کش‌های ثبت‌شده مثل برومایسید ام‌آ و امیزینگ کارایی مطلوبی نشان داد.</span></span><span dir="RTL" lang="AR-SA" style="font-size:12.0pt"><span arabic="" style="font-family:" traditional=""> </span></span></div> <pre style="text-align:justify"> Extended Abstract Introduction: Weed competition remains one of the most significant constraints to achieving optimal corn (Zea mays L.) yields, particularly during the critical early growth stages when the crop exhibits limited competitive ability against invasive weed species. In Iran&rsquo;s major corn-producing regions, annual broadleaf weeds such as Amaranthus retroflexus, Chenopodium album, and Xanthium strumarium have emerged as particularly problematic, capable of causing yield losses exceeding 40% under severe infestation. Chemical control remains the most efficient and economically viable weed management strategy; however, the heavy reliance on a limited range of herbicides most notably the environmentally concerning atrazine has led to multiple challenges, including the development of herbicide resistance and increased risks of environmental contamination. Therefore, the registration and evaluation of new herbicide formulations with different modes of action have become essential for establishing sustainable weed management systems that maintain high productivity while addressing these emerging threats. This study systematically evaluates the efficacy of several promising herbicide options, including thifensulfuron-methyl, terbuthylazine, bromoxynil + MCPA, and bentazon + MCPA, across three distinct agroecological zones in Iran. Particular emphasis is placed on assessing weed control spectrum, the effects of application timing, yield enhancement potential, and phytotoxicity risks. By developing science-based recommendations for herbicide selection and application protocols tailored to regional weed pressures, this research aims to contribute to more resilient and sustainable corn production systems in Iran and comparable agricultural environments facing similar weed management challenges. Materials and methods: The experiment was conducted using a randomized complete block design (RCBD) with 12 treatments and four replications during the 2022&ndash;2023 growing season. Herbicide treatments included thifensulfuron-methyl (20&ndash;36 g a.i./ha, pre-emergence), bentazon + MCPA (2 L/ha, post-emergence), terbuthylazine (1.8 L/ha, pre- and post-emergence), bromoxynil + MCPA (1.5 L/ha, post-emergence), as well as weed-free and untreated control plots. Measured parameters included weed density, dry weight reduction, visual injury (EWRC scale), and corn grain yield. Data were analyzed using SAS 9.1, and treatment means were compared using Duncan&rsquo;s multiple range test at &alpha; = 0.05. Received: May. 30, 2025; Revised: Dec. 12, 2025; Accepted: Dec. 15, 2025; Published Online: Apr. 08, 2026. * Corresponding Author: nezamabadi_n@yahoo.com Results and Discussion: Bromoxynil + MCPA (1.5 L/ha) achieved the highest weed control in Kermanshah, with 96% density reduction and 98% dry weight reduction, followed by terbuthylazine (1.8 L/ha, pre-emergence) and thifensulfuron-methyl (36 g/ha). Xanthium strumarium and Physalis divaricata were effectively controlled (>90%) by bromoxynil + MCPA. In Alborz, bromoxynil + MCPA and 2,4-D + MCPA provided complete weed control, whereas lower doses of thifensulfuron-methyl (20&ndash;28 g/ha) were less effective. In Ardabil, thifensulfuron-methyl (32&ndash;36 g/ha) and pre-emergence terbuthylazine reduced weed density by 85&ndash;91%, with Abutilon theophrasti controlled at approximately 75%. Yield increases ranged from 13% to 40% across treatments, with bromoxynil + MCPA and terbuthylazine performing comparably in weed suppression and yield enhancement. These results provide compelling evidence that strategic herbicide application can substantially improve weed management and yield potential in corn production systems. Overall, bromoxynil + MCPA (post-emergence) and terbuthylazine (pre-emergence) emerged as the most effective treatments, providing over 85% control of economically important broadleaf weeds, including A. retroflexus, C. album, and X. strumarium, across diverse agroecological zones. Although thifensulfuron-methyl demonstrated promising activity, its optimal performance required precise dosage calibration (32&ndash;36 g/ha), underscoring the importance of accurate application in modern weed management practices. Conclusions: The consistent 13&ndash;40% yield enhancement across all effective treatments compared with untreated controls highlights the substantial return on investment achievable through proper herbicide use. Minimal phytotoxicity observed across treatments confirms the crop safety of these herbicides when applied in accordance with recommended guidelines. Regional variations in herbicide performance emphasize the necessity of adapting weed management strategies to local weed spectra and environmental conditions to maximize efficacy. These findings have significant implications for the sustainable intensification of corn production in Iran and similar agroecosystems. By offering effective alternatives to older herbicides such as atrazine, the results contribute to resistance management and environmental safety. Future research should focus on (1) developing integrated weed management systems combining chemical and cultural practices, (2) exploring tank-mix strategies for broader weed control, and (3) conducting long-term studies on herbicide resistance dynamics. Implementing these science-based recommendations will enhance both the economic viability and environmental sustainability of corn production under increasing weed pressure and regulatory constraints. <span style="font-size:10pt"><span courier="" new="" style="font-family:"><span style="font-size:12.0pt"><span style="font-family:"Times New Roman",serif"></span></span></span></span></pre> پهن‌برگ‌های یک‌ساله, تربوتیلازین, تیفن سولفورون- متیل, عملکرد دانه. Annual broadleaf weeds, Terbuthylazine, Thifensulfuron-methyl, Corn yield, Herbicide efficacy. 19 36 http://jcpp.iut.ac.ir/browse.php?a_code=A-10-3872-1&slc_lang=fa&sid=1 Noushin Nezamabadi نوشین نظام آبادی nezamabadi_n@yahoo.com Yes Iranian Research Institute of Plant Protection (IRIPP), Agricultural Research Education and Extension Organization (AREEO), Tehran, Iran. موسسه تحقیقات گیاه پزشکی کشور، سازمان تحقیقات، آموزش و ترویج کشاورزی، تهران، ایران. Rasoul Fakhari رسول فخاری rasoulfar100@gmail.com No Plant Protection Research Department, Ardabil Agricultural and Natural Resources Research and Education Centre, (AREEO), Moghan, Iran. بخش تحقیقات گیاهپزشکی، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان اردبیل، سازمان تحقیقات، آموزش و ترویج کشاورزی، مغان، ایران