سمیه تکاسی

Araujia sericifera Brot., a species from Apocynaceae, is native to South America. A. sericifera is a perennial vining plant that grows highly dense and heavy foliage; it covers the canopy of the host tree and reduces its growth, dries the tree branches, and then destroys it. This plant is on the EPPO warning list and is developing as a weed. The first report of A. sericifera presence in Iran was from the citrus orchards of Mazandaran province (N Iran) in 2014; in Gilan province, it has been found in suburban areas, forest margins, roadsides, waste areas, the edges of tea gardens, poplar plantations, citrus, and kiwi orchards. With the dramatic increase in the population of invasive plants in Gilan province, there was a concern that if the Hyrcanian forests were invaded, the damage would be uncontrollable and costly. Given the significant threat posed by this invasive plant species to Gilan province, it was considered essential to provide a comprehensive overview of its biological characteristics, current distribution patterns, and appropriate management techniques to inform effective crisis management planning.

Continuous rice cultivation in the paddy fields of northern regions in Iran has led to the spread of weeds such as Echinochloa crus-galli and Paspalum distichum gradually. The presence of these grass weeds in paddy fields leads to waste of water and nutrients and adversely affects on rice productivity. Herbicide application helps for keeping the fields free of weeds during the critical period and minimize the costs of weeding and allows for selective weed control. No repeated application of herbicides or mixed application of herbicides are necessary, because these strategies need to prevent herbicide resistance in weeds. This experiment aimed to assess and compare the effectiveness of some herbicides, including metsulfuron-methyl, tiobencarb, bispyribac sodium, triafamon + ethoxysulfuron, cyhalofop-butyl, and the tank mixed application of cyhalofop-butyl and bispyribac sodium, in controlling grassy weeds in the rice fields.  

A field experiment was conducted in Gilan Agricultural and Natural Resources Research and Education Center (Rasht) in 2021, utilizing a Randomized Complete Block Design (RCBD) with three replications and 15 treatments, including tiobencarb 50%EC at 2750 and 3000 g a.i. ha-1, bispyribac sodium 40%SC at 26 g a.i. ha-1, triafamon+ethoxysulfuron 30%WG at 37.5 and 45 g a.i. ha-1, cyhalofop-butyl 20%OD at 100 g a.i. ha-1, bispyribac sodium 40%SC at 26 g a.i. ha-1 + cyhalofop-butyl 20%OD at 100 g a.i. ha-1, metsulfuron-methyl 60%DF at 6 and 8 g a.i. ha-1, pertilachlor 50%EC at 875 g a.i. ha-1, twice hand weeding, and weedy check. Thiobencarb, pertilachlor, and triafamon + ethoxysulfuron were applied in water, five days after transplanting, and cyhalofop-butyl, metsulfuron-methyl, and bispyribac sodium were applied to the weeds at the two- to four-leaves stage, using a knapsack sprayer equipped with a flat fan nozzle. Weed control via application of herbicides was evaluated visually based on the European Weed Research Society rating scale and weed density and biomass were assessed. The yield of rice from each plot was measured. The data collected for different parameters were subjected to analysis of variance (ANOVA) using R-studio and the treatment means were compared using Duncan's Multiple Range Test at a significance level of 1%.

All weed control treatments significantly increased the weed control efficiency (WCE) over the weedy check. Triafamon + ethoxysulfuron and tiobencarb in both examined doses had the highest WCE in reducing E. crus-galli pressure with 100% control. After that the effectiveness of pertilachlor at 875 g a.i. ha-1and cyhalofop-butyl at 100 g a.i. ha-1 in reducing E. crus-galli density was ≥90% and biomass reduction was ≥78%. There were no significant differences between these treatments in controlling E. crus-galli. The highest WCE in P. distichum control was observed in applying triafamon + ethoxysulfuron at doses of 37.5 and 45 g a.i. ha-1 with ≥91.1% and ≥94.4% density reduction and ≥95.6% and ≥99.8% biomass reduction, respectively; followed by application of cyhalofop-butyl with ≥83.6% and ≥79.7%, density and biomass reduction, respectively. After that, tiobencarb in both doses resulted in ≥72% density reduction and ≥84.5% biomass reduction. There was no significant difference between these treatments in P. distichum control. Pertilachlor was not very effective in controlling of P. distichum; its efficacy was 48.8, 56.5, and 78.4% biomass reduction, in three samplings, respectively. The highest efficacy of metsulfuron-methyl in controlling E. crus-galli and P. distichum was 75.9 and 73.1%, respectively for biomass reduction in the first sampling in the application of 8 g a.i. ha-1. Herbicide application resulted in improved rice grain yield compared to the weedy check. The highest grain yield of rice was achieved with tiobencarb at doses of 3000 and 2750 g a.i. ha-1, yielding 5051 and 4965 Kg ha-1, respectively. There was no significant difference between observed manually weeded treatment and thiobencarb treatments, and also with bispyribac sodium, pertilachlor, triafamon + ethoxysulfuron in both doses (45 and 37.5 g a.i. ha-1), and cyhalofop-butyl; these treatments increased grain yield by 68.4, 65.5, 54.56, 52.8, 39.2, 35.4, 34.6%, respectively, compared to the weedy check. 

The results of this research showed that application of triafamon + ethoxysulfuron at 37.5 g a.i. ha-1 or thiobencarb at 2750 g a.i. ha-1 applied at 3-5 days after rice seedlings transplanting into the water, or application of cyhalofop-butyl at 100 g a.i. ha-1 in the form of a foliar spray in the stage of two- to four-leaf of grass weeds were the efficient control practice for both grass weeds (E. crus-galli and P. distichum) in paddy field. 

Slow growth of groundnut (Arachis hypogaea L.) makes it a poor competitor against weeds. The presence of weeds in fields leads to waste of water and nutrients and provides a habitat for growth of pathogens and insect pests, which adversely affects plant productivity. Herbicide application for keeping the fields free of weeds during the critical period of weed control helps minimize the costs of weeding. This experiment was carried out to determine the appropriate dose of quizalofop-P-ethyl for effective control of grass weeds in groundnut fields.

Field experiments were conducted in a randomized complete block design with nine treatments and four replications in Guilan, Ardabil and Golestan provinces. Quizalofop-P-ethyl 8.8%EC at four doses included 500, 550, 600 and 650 ml ha-1 (Kimia Sabz Moghan Company) was investigated for grass weed control and compared with haloxyfop R methyl ester 10.8%EC (0.75 L ha-1), clethodim 12%EC (1 L ha-1), sethoxydim 12.5%EC (3 L ha-1), fluazifop-P-butyl 15%EC (3 L ha-1).

Application of quizalofop-P-ethyl 8.8% EC at 500, 550, 600 and 650 ml ha-1 in Guilan province, led to 72, 79, 90, 85% number reduction and 70, 87, 96, 92% dry weight reduction of grass weeds (E.crus-galli and S.glauca) compared to weedy check, respectively. In Ardabil province, the control efficacy of quizalofop-P-ethyl at these doses for the number reduction of E. crus-galli was 57, 74, 90, 92%, respectively and for dry weight reduction was 60, 71, 90, 92%, respectively and for S.glauca, the number reduction was 46, 60, 71, 69%, respectively of and the dry weight reduction was 57, 84, 93, 92%, respectively. In Golestan province, application of quizalofop-P-ethyl at these doses led to 19, 24, 57, 58% number reduction, respectively and 23, 53, 78, 78% dry weight reduction of E. colonum, respectively and 33, 35, 39, 53% number reduction, respectively and 51, 59, 90, 92% dry weight reduction of S. glauca, respectively and 53, 61, 66, 58% number reduction, respectively and 87, 90, 92, 87% dry weight reduction of S. vercillata, respectively. In comparison between all treatments, the highest weed control efficiency of E. crus-galli with ≥ 90% was occurred in application of fluazifop-P-butyl and quizalofop-P-ethyl 600 and 650 ml ha-1 and then in quizalofop-P-ethyl 550 ml ha-1 with 71-79% density and dry matter reduction. The highest weed control efficiency of E. colonum was achieved in fluazifop-P-butyl, quizalofop-P-ethyl 600 and 650 ml ha-1, sethoxydim and clethodim which were ≥70% dry matter reduction of weed. In control of S. glauca, except of quizalofop-P-ethyl 500 ml ha-1, other treatments had effective weed control efficiency (≥ 80%). Dry weight reduction of S. verticillata, was achieved ≥85% compared to control with treatments. The highest yield increase in comparison to control in Guilan was achieved with the application of quizalofop-P-ethyl 600 ml ha-1, clethodim, quizalofop-P-ethyl 550 ml ha-1 and sethoxydim (74, 73, 70.5 and 61% respectively); in Ardabil, with application of quizalofop-P-ethyl 600 ml ha-1, sethoxydim, quizalofop-P-ethyl 650 and 550 ml ha-1 and fluazifop-P-butyl (162, 160, 156, 149 and 148%) and in Golestan with application of clethodim, quizalofop-P-ethyl 550 and 600 ml ha-1 and sethoxydim (297, 297, 261 and 243% respectively).

Due to the effective efficiency on quizalofop-P-ethyl 8.8% EC herbicide in control of grass weeds and producing a high groundnut yield compared to weedy control, it can be stated that this herbicide at a dosage of 600 ml ha-1in the form of a foliar spray in the stage of two- to four-leaf of narrow-leaf weeds is recommendable as an efficient herbicide to control of narrow-leaf (grass) weeds.

This experiment was performed to determine the appropriate dose of Cyhalofop-butyl (CB) for controlling grass weeds in transplanted rice. CB at four doses, including 50, 100, 150, and 200 g ai/ha was investigated and compared with current herbicides in rice at recommended doses. The results showed that CB 100, 150, and 200 g ai/ha significantly reduced the density and dry matter of Echinochloa crusgalli (L.) P. Beauv. and Paspalum distichum L. over the weedy check; the minimum control efficacy of CB at these doses was 73.3 and 88.3% for E. crusgalli density and dry matter reduction, respectively, and for P. distichum, it was 80% for density and dry matter reduction. Applying CB at all doses (50- 200 g/ha) showed no crop injury symptoms on rice plants. The highest grain yield was obtained by hand weeding, CB 150 g ai/ha, and Tiobencarb treatments, with 5180, 5106, and 5051 Kg/ha, respectively. CB 200 g ai/ha was on par with CB 150 g ai/ha, and there was no significant variation between CB 100 and 200 g ai/ha in rice grain production. Finally, it was found that the application of CB 100 g ai/ha is an efficient grass weed control practice for improving the rice yield.

In order to control the invasive weed, Eichhornia crassipes (Mart.), two experiments were carried out during 2017 and 2018 in Gilan province. The first experiment was carried out in Anzali Lagoon to investigate the efficacy of Glyphosate (41%SL) at 2 and 3 Lha-1 (two applications), Glyphosate at 2 and 3 Lha-1 plus Dasher Adjuvant (0.5%) (two applications), Glyphosate at 2 and 3 Lha-1 plus Ammonium Sulfate Adjuvant (2%) (two applications) and Glufosinate-ammonium (15% SL) at 2.5 and 5 Lha-1. The second experiment was carried out in mesocosm to compare the efficacy of Glyphosate at 3 Lha-1 (two applications), Glyphosate at 3 Lha-1 plus Ammonium Sulfate (two applications), Glufosinate-ammonium at 5 Lha-1 and Bispyribac sodium (12.5% SC and 10% OF) at 200 and 300 mlha-1 (two applications). EWRC rating scale for visual control and the wet and dry weight reduction of water hyacinth were checked in comparison with the weedy check within 30 days after herbicide application. The Results of visual control in both the experiments indicated that the best treatment was Glyphosate at 3 Lha1 with 98% weed control and in the second experiment in this treatment wet and dry weight reduction was 56% and 64% compared to weedy check, within 30 days after herbicide application and complete control within three months after application respectively. Bispyribac sodium (10%OF) at 200 mlha-1 had 63% visual control, 33% and 56% wet and dry weight reduction compared with the weedy check within 30 days after herbicide application and complete control within three months after application, respectively.

During the study of the habitats and ecosystems of Gilan province (north of Ian), an invasive and alien species, namely, Tradescantia fluminensis (Commelinaceae) was observed and identified which is reported for the first time for the flora of Iran. In recent years, T. fluminensis has been developed as a weed in tea gardens and an invasive plant in the neighboring plains of the northern parts of Iran. In addition, the report of the growth localities as well as the risk assessment of the invasive plant were examined using the protocols provided by Virtue & Meland (2003), and Stone (2008). According to the risk score obtained for this invasive plant (205.86), it stands within the group of plants with "very high risk". By studying the soil of habitats, it was found that, there is a positive and significant correlation between the amount of available soil phosphorus and the wet biomass of the plant. Due to the ecological behavior of this plant, biological control and mechanical removal are the most appropriate methods of managing this plant in the northern habitats of the country.

This study was done to compare the plant morphology of Ambrosia psilostachya DC. (ragweed) in four habitats of roadsides (1), paddy field margins (2), around residential areas (3) and coastal areas (4) in Bandar-e Anzali (Guilan province, north of Iran) in 2019. Sampling was random in five growth stages with 10 plants in each habitat. The results indicated that, the highest biomass, plant height and inflorescence length was in the habitats of (2) & (4), and the highest inflorescence numbers was in (3) & (2). The maximum plant biomass in the habitats of (2), (1) & (4) was 110 days, and in (3) was 82 days after the emergence and then the plant entered the reproductive phase. The trend of plant height increased in the habitat of (1) continued up to 69 days, and in (2) & (4) continued up to 110 days after emergence and then decreased while in habitat of (3), the trend was linear and continued until November. The beginning of flowering was in mid-July in all habitats. The increasing trend of number of flowering stems in habitats of (3) & (4) was up to 82 days after emergence, but in (2) & (1) had a linear trend and continued until November.

Seed germination and emergence is a key event that determines the success of a weed in an agro ecosystem that is influenced by many environmental factors such as temperature, pH, light, salinity and moisture (Chauhan & Johnson, 2008). Temperature plays a major role in determining the periodicity of seed germination, emergence and the distributions of weed species (Guan et al., 2009). Also, osmotic stress can reduce, delay or prevent germination (Zhou & Deckard, 2005). An understanding of weed development is needed to design effective weed management programs. A better understanding of the biology of seed germination and emergence could contribute to the development of weed management technologies to help counter those undesirable shifts in weed populations. The hydrothermal time models have been widely applied to describe the germination responses of seeds to temperature and water potential. This study was carried out with the aim to predict the time and maximum seedling emergence of two weed species, wild barley (Hordeum spontaneum Koch.) and prickly lettuce (Lactuca serriola L.).

Different temperatures (15, 25 and 35°C) and water potentials (-0.045 and -0.172 MPa) as full factorial experiments applying a randomized experimental design with four replications were investigated in laboratory and planting dates (October and November) for H. spontaneum seeds and March, April and May for L. serriola and three irrigation intervals: every 3 days once (level1), every 5 days once (level2) and every 7 days once (level3) for two species as full factorial experiments applying a completely randomized experimental design with three replications were investigated in field. To express the changes in the emergence process, hydrothermal time model was applied and the base temperature and water potential were calculated. Then, MPa-°C-days required for emergence was calculated with the base temperature and water potential and soil moisture and temperature.

The results of the laboratory experiments showed that the maximum germination percentage of wild barley at 15 and 25°C was 95.9 and 83.7 %, respectively and for prickly lettuce at 15, 25 and 35°C was 96.3, 79.9 and 60.9 %, respectively. The highest and lowest maximum emergence percentage of wild barley was at 15°C, -0.045 MPa and 25°C, -0.172 MPa, respectively that was 92.6 and 66.3 %, respectively and for prickly lettuce was at 15°C, -0.045 MPa and 35°C, -0.172 MPa, respectively that was 95.5 and 20.0 %, respectively. Thermal time required for germination of wild barley at 15 and 25 °C was 43.8 and 65.1 °C-days, respectively and for prickly lettuce at 15, 25 and 35 °C was 44.6, 31.7 and 32.9 °C-days, respectively. The highest and lowest thermal time required for 50% emergence of wild barley was at 25 °C, -0.045 MPa and at 15°C, -0.172 MPa, respectively that was 209.6 and 99.8 °C-days, respectively and for prickly lettuce was at 15°C, -0.172 MPa and at 35°C, -0.172 MPa, respectively that was 70.0 and 49.7 °C-days, respectively. The results of the field experiment showed that the highest emergence percentage of wild barley and prickly lettuce was 97.6 and 56.2% that occurred in November with irrigation interval of every 3 days once and April with irrigation interval of every 5 days once, respectively. The lowest emergence percentage of wild barley and prickly lettuce was 78.2 and 21.3% that occurred in October with irrigation interval of every 3 days once and May with irrigation interval of every 7 days once, respectively. The highest hydrothermal time for 50% emergence of wild barley and prickly lettuce was 384.2 and 179.2 °C-days-MPa in October with irrigation interval of every 7 days once and May with irrigation interval of every 5 days once and the lowest was 84.6 and 43.3 °C-days-MPa in November with irrigation interval of every 3 days once and march with irrigation interval of every 3 days once, respectively.

To evaluate the efficacy of bispyribac sodium SC42% herbicide (Rissin) on rice weeds control in transplanting method and comparing it with some registered herbicides, an experiment was carried out in two regions, Guilan (Rasht) and Mazandaran (Sari), Iran, in 2019. Treatments consisted as bispyribac sodium SC42% at four doses (50, 54, 58 and 62 ml.ha-1), bispyribac sodium OF10% at 250 ml.ha-1, bispyribac sodium SC40% at 65 ml.ha-1, oxadiargyl EC30% at 3.5 L.ha-1, triafamon + ethoxysulfuron WG30% at 150 g.ha-1, pertilachlor EC50% at 2  L.ha-1, together with two check treatments (weed free and unweeded treatment). The experiment was performed in randomized complete block design with three replications. The results showed that Rissin had good efficacy on weed control and did not cause rice damage even at the highest used dose. The efficacy of Rissin for weed control at three doses of 54, 58 and 62 ml.ha-1 was 85-91% for barnyardgrass (Echinochloa crus galli L.), 66-90% for nutsedges (Cyperus difformis L.) and 95-97% for crowngrass (Paspalum distichum L.) in Sari and 60-93% for barnyardgrass, 60-100% for nutsedges and 30-77% for crowngrass in Rasht. Weed biomass in the experimental field in Sari was lower than in Rasht, which explains the reason of the different control results. Rissin at the three higher doses had similar efficacy to commercial doses of the registered herbicides for weed control and in term of rice yield components (such as tiller and panicle number, biological yield and grain yield), the best result was obtained at 62 ml.ha-1 of Ressin and was similar to weed free treatment.

Experiments, in Petri dish and greenhouse, were carried out to investigate the efficiency of three herbicides (rimsulfuron, imazapic and imazamox) in controling broomrape. In Petri dish study, herbicides were applied at 0.05, 0.25, 1.25, 6.25 and 31.25 micro-mole doses to broomrape seeds at germination stage without a host plant and adding GR24 as stimulator. In the greenhouse experiments, the efficiency of these herbicides to control broomrape in two varieties of tomato (Viva and Hyb.Petopride II) was investigated. Treatments were four doses of rimsulfuron (25, 50, 75 and 100 g ai/ha), imazapic (5, 10, 15 and 20 g ai/ha) and imazamox (0.4, 0.8, 1.2 and 1.6 g ai/ha) at one, two and three applications. Results of Petri-dish experiments showed that rimsulfuron and imazapic significantly reduced radicle elongation of seedlings as compared to the control, while, imazamox did not have any effect on broomrape seed. Each dose was applied for one, two and three times with in 15, 29 and 43 days after within transplanting tomato seedlings. Results of pot experiments indicated that the responses of two tomato varieties herbicides were different. Viva was responsive to herbicidal effect and produced higher biomass than Hyb.Petopride II. Rimsulfuron was a suitable herbicide in tomato to control broomrape. Rimsulfuron at doses of 25, 50 and 75 g ai/ha (three times of application) were the best doses, specially in viva were the best treatments for broomrape control and producing tomato biomass. Imazapic also, at 5 g ai/ha (two times of application) and 10 g ai/ha (single application) was an effective treatments in variety of viva. Imazamox treatments did not appear to be suitable herbicides in this study.

In this study، the susceptibility of twenty-nine tomato varieties to broomrape infection under glasshouse conditions was investigated. Results showed that Differences in susceptibility to infection were significant among tomato varieties. Significant differences were in number and time of broomrape shoots emerging، broomrape dry weigh (shoots and tubercles) and growth and fruit yield of tomato. Moderate levels of resistance were obtained in Viva، Caligen 86، Hyb. PS 6515، Hyb. Firenze (PS 8094) and Cal-jN3 among other tomato varieties. In contrast، varieties of Kimia-Falat، Hyb. Petopride II and Hyb. AP865 were the most susceptible hosts to Orobanche aegyptiaca.

For investigating of O. aegyptiaca control in tomato with sulfosulfuron and glyphosate and evaluating the efficacy، dose and time of application، some studies were conducted in 2011 at Aarhus university of Denmark. At first، the efficacy of sulfosulfuron (0. 029، 0. 147، 0. 735، 3. 676 and 18. 378 mg per lit) and glyphosate (0. 023، 0. 117، 0. 587، 2. 935 and 14. 676 µl per lit) on Egyptian broomrape seeds were tested in vitro without a host plant by using of GR24. Then، the efficacy of these herbicides for broomrape control in two varieties of tomato (Viva and Hyb. Petopride II) in greenhouse conditions was investigated. Treatments in greenhouse experiments were four doses of sulfosulfuron (25، 50، 75 and 100 gr ai/ha) and glyphosate (20، 40، 60 and 80 gr ai/ha) at one، two and three application. First application was conducted 15 days after tomato seedlings transplanting and the time between two applications was 14 days. Results of Petri-dish experiment showed that both herbicides significantly reduced radical length of broomrape seeds compared to the untreated control. In pot experiments، two tomato varieties responses to herbicides were different. Viva cultivar was better than Hyb. Petopride II Cultivar in both herbicide applications. Sulfosulfuron at doses of 50 gr ai/ha (one، two and three times of application) and 25 gr ai/ha (two and three times of application) viva cultivar were the best treatments for broomrape control and producing tomato biomass. Also، glyphosate at doses of 20 and 40 gr ai/ha (one، two and three times of application) in this variety was safe for tomato and controlled broomrape. Sulfosulfuron was a safer herbicide than glyphosate for broomrape control in tomato