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 Field experiments were conducted in 2012 and 2013 at the Teaching and Research Farm of the University of Calabar, Cross River State, Nigeria to determine the effectiveness of integration of Fitsextra® (a solution containing Atrazine and Metolachlor herbicides as active ingredients), egusi melon and hand-weeding on weed management and tuber yield of cassava. The twelve treatments which involved individual and combinations of the above mentioned weed control methods were laid out in a randomized complete block design and replicated three times. Irrespective of the method adopted, weeding depressed weed density by 57.33 % and 63.99 % in 2012 and 2013, respectively and weed biomass by 81.00 % and 79.64 % within the same period compared with the unweeded check. Integration of Fitsextra with egusi melon and/or hand-weeding significantly (P<0.05) suppressed weeds more than the sole use of Fitsextra® or egusi melon. Integration of hand-weeding with Fitsextra and/or egusi melon reduced weed dry matter by 43.46, 87.25, 92.34 and 93.51 % in 2012, and by 53.20, 90.20, 94.61 and 94.56 % in 2013 compared with hand-weeding alone, Fitsextra alone, egusi melon alone and no weeding, respectively. Plots that were hand-weeded thrice and those treated with Fitsextra + hand-weeding twice significantly (P<0.05) produced the highest fresh tuber yield of 9.73 and 10.23 t/ha, respectively in 2013. No weeding reduced cassava tuber yield by 4.83 t/ha (84.89 %) on a 2-year average, compared with the weeded plots. Conclusively, the results indicated that, three hand-weeding optimized cassava tuber yield, however, the integration of Fitsextra or egusi melon can effectively replace the first hand-weeding.

Abstract Weeds could replace the cultivated fodders in case of fodder shortage. But most of farmers are not aware about the potential of traditional weeds in croplands. Thus, an experiment was conducted to estimate the nutritional quality of some forage weeds with respect to their phonological development. Quantitative and qualitative parameters were recorded and analyzed statistically by analysis of variance technique and means of treatments were compared by least significant difference test. Qualitative traits of selected weeds were determined through the methods developed by The Association of Official Analytical Chemists (AOAC). The results showed that the quantitative traits of weeds differ from each other. It was found that the moisture decreased from vegetative (86.13-90.92%) to post reproductive stage (86.77-73.56%) and crude protein decreased from vegetative (16.95-23.40%) to post reproductive stage (11.52-15.09%) in all weeds. Similarly ash contents decreased from vegetative (13.72-23.40%) to post reproductive stage (9.26-13.11%) in all weeds. The crude fats were nearly similar in all stages (1.75-2.00%). Dry matter and crude fiber increased (9.08-13.87 to 13.23-26.44% and 9.86-21.95 to 21.58-31.63%, respectively) from vegetative to post reproductive stage. Overall results declared that the biomass produced by weeds was a luxurious source for livestock production during the vegetative stage of growth as the nutritional quality decreased from vegetative to post reproductive stages. Further research is needed to explore the forage quality of all common weeds present in croplands.

Abstract Corn is one of the strategic food commodities in Indonesia which is currently widely used as animal feed ingredient. But the average productivity of national corn is still low. This study aims to determine the dose of herbicide ammonium glufosinate 200 g/L which can maintain the growth potential and yield of corn plants. The experiment was carried out at the Ciparanje Experimental Garden of the Faculty of Agriculture, Padjadjaran University, Jatinangor, Sumedang Regency, West Java, with altitude of 750 meters above sea level in November 2017 to March 2018. The experimental method used was a randomized block design consisting of seven treatments which were repeated four times. The treatments tested consisted of: manual weeding, application of different doses of ammonium glufosinate (450, 600, 750, 900, and 1050 g/ha) and unweeded check. The results of the experiment showed that application of ammonium glufosinate 200 g/L herbicide is able to suppress weed growth in corn cultivation. The application of ammonium glufosinate 200 g/L herbicide starting from a dose of  600 g/ha is effective in suppressing weed growth and suppressing the loss of yield of corn due to the presence of weeds.

Abstract Coastal areas are famous for its diversity and abundance of marine flora and fauna. Several tonns of seaweeds grows annually and during low tide they are easily avaliable either in growing or drift form. The current investigation was focus to target these marine flora to provide an alternative to toxic colorants. The brown seaweed, Stoechospermum marginatum were collected form the coastal area of Arabian sea during low tide. Seaweed colorants can be used as sustainable and eco-friendly source to make a value added product. Extraction process were optimized by varying solvent medium (alkali, acidic and distilled water), solvent concentration and extraction time. Eco-friendly metal salt like ferrous and alumium sulphate were used to developed twenty-four soft shades on S/J 100% cotton. Dye exhaustion, color measurements and fastness properties such as wash, crock and light fastness of resultant fabric have been studied. The optimized condition of extraction process was 5g/L sodium hydroxide for 3hrs processing time. The dyed fabric having 5g/L sodium hydroxide extarcted dye and mordanted with ferrous sulphate shows maximum exhaustion percentage as well as good to very good fastness property while the Δa and Δb values of color measurements shows that the dyed fabric has reddish-yellow shade.

Abstract A field study was carried out in Uyo, Southeastern Nigeria in 2011 and 2012 to compare the potential of using pumpkin intercrop as a means of cost effective weed management in water yam (Dioscorea alata) farm. The experiment was laid out in a randomized complete block design. The treatments were included no weeding, weeded (3x), chemical weeding (Raft 500) + supplemented hoe weeding at 12 weeks after planting (WAP), Dynamic population densities of 10,000, 20,000, 30,000 and 40,000 supplemented with one hoe weeding at 4 WAP. The result of the study showed that weeded 3x treatment performed better in all the growth and yield parameters assessed but not significantly (P<0.05) above the growth and yield values obtained from 30,000 population density of pumpkin. The weeded (3x) resulted to tuber yield of 22.81 and 20.75 t.ha-1 in 2011 and 2012 respectively, while, the 30,000 pumpkin population density had tuber yield of 19.81 and 19.35 t.ha-1 in 2011 and 2012 respectively. The least tuber yields 3.22 and 2.18 t.ha-1 was obtained from no weeding treatment. The weeded (3x) treatment had 9-86 and 8-90 percentage tuber yield above other treatments but 13 and 8% over 30,000 pumpkin population density alone. The study suggests that pumpkin intercrop at 30,000 stands per hectare could effectively reduce weed interference in water yam farm.

Abstract Smallholder farmers have challenges of weed control and mostly they use cultural control methods because chemical control with herbicides is usually costly. However, Lantana camara L. is known to be allelopathic to other plants hence a worthy candidate for biological control of weeds under cowpea production. A field study was conducted to determine the potential for L. camara to control weeds in cowpea at the University of Zambia Agricultural Experimentation Station. Leaves were harvested from two genotypes of L. camara (G1: Pink-flowered and G2: Orange-flowered genotypes) dried and pulverized to form a powder and applied at different rates (R0C: 0 kg ha^-1, R1: 100 kg ha^-1, R2: 200 kg ha^-1, R3: 400 kg ha^-1) using the following types of application: T0C: No application, T1: broadcasting, T2: incorporation in the soil and T3: spraying of soaked ground L. camara. The research was conducted at the University Of Zambia School Of Agricultural Sciences Field Station. The experiment was arranged in a split split-plot design with three replications. Weed population density and weed weight were reduced the most (38% and 12.5%, respectively) at the highest rate (R3: 400 kg ha^-1) of L. camara application. The cowpea grain yield was higher (P< 0.05) in fields treated with G1 (mean =876.90 kg ha^-1) than for G2 (mean =672.10 kg ha^-1). G1 increased cowpea grain yield by 36.04%. Lantana camara holds great potential to increase food security by reducing losses associated with weeds in cowpea.

Abstract The bio-efficiency of imazethapyr and its ready mix combination products with pendimethalin and imazamox against weeds, their effect on growth, yield and phytotoxic effects on black gram and residual effect on succeeding mustard crop were studied during 2013-14. Significantly lower weed count and dry weight was recorded with application of imazethapyr + pendimethalin (pre-mix) at 800 g/ha, pendimethalin at 1000 g/ha and imazethapyr + pendimethalin (pre-mix) at 900 g/ha. Imazethapyr + pendimethalin (pre-mix) 1000 g/ha and 800 g/ha, pendemethlin 1000 g/ha and imazethapyr 50 and 70 g/ha (pre emergence) behaving statistically similar with pendimethalin 1000 g/ha (pre emergence) and hand weeding at 20 and 40 days after sowing resulted in significantly higher seed yield of black gram. Seed yield of blackgram was negatively associated with total weed count and weed dry weight (P≤0.01). With every one weed increase per square meter, the blackgram seed yield was expected to reduce by 16.8 kg/ha. Net returns, B:C and net returns over weedy check were highest under imazethapyr + pendimethalin 900 g/ha. The economic threshold levels i.e. No m^-2 and g m^-2 with the weed management practices studied varied between 1.7 – 18.0 m^-2 and 1.0-10.0 g m^-2. Imezethapyr + pendimethalin 1000 g/ha and imazethapyr + imazamox 50 g/ha had lowest weed persistence index (WPI). Imazethapyr + pendimethalin 900 g/ha resulted in highest crop resistance index. Weed management index (WMI), Agronomic management index (AMI), and Integrated weed management index (IWMI) were highest following imazethapyr 40 g/ha. Overall impact index (Ii) was highest under imazethapyr 50 g/ha followed by imazethapyr + pendimethalin 900 g/ha, imazethapyr + pendimethalin 1000 g/ha and pendimethalin 1000 g/ha. Weed index (WI) indicated 70.8% loss in yield of blackgram. The residual effects of herbicide treatments on succeeding mustard crop were not observed.

Abstract Since its introduction into Ethiopia during 1970s, Prosopis juliflora, became an environmental issue in areas where it was first introduced to combat desertification. This review paper was aimed at reviewing some adverse effects of the plant on socioeconomic, environmental and biodiversity with its control practices in the eastern Ethiopia. Contrary to its purpose of introduction, this plant has been found to be highly invasive and, it imposed adverse effects on the native plant species. The plant is declared as an invader which has put impacts on socioeconomic, environment, and biodiversity of the eastern region of Ethiopia especially afar region and Dire Dawa; which became alarm for pastoralists, development agents, scientists, and policy makers. Though cultural practices such as burning and cutting were mainly practiced, the invasion could not be stopped.

Abstract 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.

Abstract Water hyacinth is free-floating, stoloniferous and perennial herb. It is an aquatic invasive species; native to South America and most aggressive invasive species worldwide. It profoundly invaded the tropical and subtropical region of the world, as a result of ornamental properties and reproductive capability of the weed. In addition, it is recognized as one of the worst weeds due to its rapid proliferation rate, ecological adaptability and detrimental effects on environment, human health and economic development. It poses serious socio-economic and environmental problems includes destruction of biodiversity, hindrance to water transport and recreation, oxygen depletion and reduction of water quality, breeding ground for pests, vectors and their effect on human health, hampering agriculture and fisheries, affect hydropower and water supply systems and increased evapo-transpiration. Therefore deferent management strategies such as physical, chemical and biological methods had been used to control the weed. Accordingly manual removal was used in South Africa; Zimbabwe Lake Mutirikwi; Ethiopia Wonji-Shewa Sugar Factory and Owen fall hydropower in Jinja at Lake Victoria. Chemical control was practiced in Zimbabwe Lake Chivero using 2-4-D; South-west Nigeria Ere fishing channel by glyphosate; South Africa larger dams and river systems by using glyphosate; Zimbabwe acetic acid and glyphosate control the weed at experimental site. Biological control was practiced in Zimbabwe Lake Chivero through combination of weevil and fungi; Kenya Lake Victoria and China by two types of weevils (Neochetina bruchi and Neochetina eichhornia) and Ethiopia Neochetina bruchi and fungi at Rift Valley and in green house at experimental level respectively.

Abstract The present study was carried out to evaluate the efficacy of botanical extracts on the management of Parthenium hysterophorus through laboratory experiments. These experiments were carried out at Department of Agronomy, Agricultural College and Research Institute, Madurai during 2013-15. The efficacy of twenty botanicals viz., Abutilon indicum, Amaranthus spinosus, Amaranthus viridis, Azadirachta indica, Calotropis gigantea, Croton bonplandianum, Cynodon dactylon, Cyperus rotundus, Datura metel, Echinochloa crusgalli, Helianthus annuus, Lawsonia inermis, Mangifera indica, Prosopis juliflora, Solanum nigrum, Sorghum bicolor, Sorghum halepense, Tagetes erectus, Tamarindus indica, Tephrosia purpurea were tried at different concentrations under laboratory bioassay. The study reveal that the per cent germination, seedling length, seedling vigor index and seedling biomass of P.hysterophorus was reduced significantly due to application of all botanicals, however the effect was more pronounced with botanicals extract  in the order of Datura metel, Mangifera indica, Azadirachta indica, Tagetes erectus, Helianthus annuus and Sorghum bicolor both at 50 and 75 % concentrations. Increased concentration (50 and 75 %) was pronounced more detrimental effects on per cent germination and seedling growth parameters of P.hysterophorus.

Abstract Field experiments were conducted on the research farm of Federal University Dutse in the Sudan savannah ecological zone Nigeria to evaluate the performance of upland rice varieties as affected by herbicide and poultry manure application. The two locations lie in the Sudan savanna ecological zone with a mean annual rainfall of 600 mm distributed between May and October. The treatments consisted of three rates of poultry manure (0, 5 and 10 t/ha) and five weed control treatments factorially combined in the main plot while two upland varieties of rice (Nerica and Faro 48) in the sub-plot. The treatments were laid out in a split-plot design with three replications. Application of pendimentaline+one hoe weeding at 6 WAS produced significantly greater plant height, leaf area, leaf area index, length panicle, panicle weight per plant, biological yield  and the grain yield of rice than the other rates comparable with the hoe weeded control while the weedy check had the least. The application of 10 t/ha of poultry manure gave significantly greater plant height, leaf area, leaf area index, length of panicle, number of grain per panicle, harvest index and the grain yield of rice than the lowest rates  (0 and 5 t/ha). It can be concluded that rice farmers in the sudan savanna zone of Nigeria can adopt 10 t/ha of manure, pendimentaline+one weeding control at 6 weeks after sown and the Faro 48 rice variety since the combination of these treatments gave better weed control, growth and yield of paddy rice.

Abstract The rapid emergence of herbicide-resistant weeds has further added complexity to the management of weeds in Australian cotton farming systems. Fleabane (Conyza bonariensis L) has been identified by the cotton industry as being potentially resistant or at risk of developing resistance. Thirty-seven C. bonariensis populations were collected in the 2014-2015 cotton season from 9 cotton farming regions in Queensland and New South Wales. Glasshouse screening trials showed that 27 populations (73%) expressed resistance to glyphosate salt at rate of 0.68 kg a.i ha^-1 applied at the rosette stage. Another 9 populations (24%) were categorised as developing resistance. A dose response study of 4 selected resistant populations using glyphosate rate of 0, 0.34, 0.68, 1.36, 2.72, and 5.44 Kg a.i ha^-1 showed a high level of Resistance Index (RI) ranging from 3.5 to 7.0 and the dose-response model revealed that 3 to 4 times more glyphosate is required to control resistant C. bonariensis populations. These results further confirm the frequent reports of reduced efficacy of glyphosate against fleabane in northern cotton farming systems of Australia. To reduce the risk of resistance other non-glyphosate tactics are needed in the weed management toolbox.

Abstract The soluble carbohydrates play a major role in germination, growth, reproduction, defense and survival of perennial plant species reproducing with rhizomes under normal and adverse environmental conditions. The information regarding the amount of carbohydrates present in the rhizomes of such species could provide valuable insights for making decisions regarding the best time to control these species. Therefore, seasonal changes in the concentrations of soluble carbohydrates (fructose, glucose, sucrose) and their sum termed as total amount of soluble carbohydrates (TSCs) in the rhizomes of Russian knapweed were investigated during 2013-2014. The TSCs were low at sprouting and then slightly increased until mid-June (beginning of flowering). Thereafter, TSCs were slightly decreased from mid-June to minimal values in August (flowering period) (6.2 mg/g), and then gradually increased until the highest values in January (170.6 mg/g). Fructose (131.5 mg/g) was detected as the main soluble carbohydrate, followed by sucrose (98.8 mg/g) and glucose (73.1 mg/g). Keeping in view the results of current study, the best time to control Russian knapweed is flowering, where the amount of TSCs in the rhizomes is minimal. It is therefore recommended that the species should be controlled either at flowering stage or during the production of first rhizomes for its sustainable management in the country.

Abstract This study was performed to evaluate the weed density and weed control efficiency (WCE) on transplanted rice under different treatments at a farmer’s field, Bhanu-11, Rupakot, Nepal during Rainy season of 2017. Ten treatments (one manual weeding at 21 days after transplanting (DAT) (T₁); two manual weeding at 21 and 42 DAT (T₂); three manual weeding at 21, 42, and 63 DAT (T₃); single cono weeding at 21 DAT (T₄); double cono weeding at 21 &42 DAT (T₅); triple cono weeding at 21, 42, and 63 DAT (T₆); butachlor as pre emergence (T₇); butachlor with single manual weeding at 21 DAT (T₈); butachlor with double manual weeding at 21 & 42 DAT (T₉) and weedy check (T₁₀) were laid in randomized complete block designs (RCBD) with three replications. At 30 DAT, the highest weed density was recorded at unweeded check (T₁₀) while it was the lowest at butachlor with double manual weeding (T₉). At 60 DAT the effective weed control method on weed density was found to be double manual weeding (T₂). At 90 DAT triple cono weeding (T₆) was found to be more effective on controlling weed density (30) and was at par double manual weeding (T₂), double cono weeding (T₅) and butachlor with double manual weeding (T₉). WCE was the highest in the plot treated with butachlor with double manual weeding at 21 and 42 DAT (T₉) and the lowest in the plot treated with butachlor pre emergence (T₇) at 30 DAT. At 90 DAT, WCE in the plot treated with triple weeding (T₆) was found the highest (78.63%) and the lowest in the plot treated with butachlor as pre emergence (T₇) (26.14%).

Abstract Growing two or more cultivars of the same crop species in mixture reduces intra-specific competition for growth resources by inducing variation in spatial and temporal patterns of crop growth, increases competitive ability of crops against weeds and thus enhances crop yield. This study was conducted to evaluate the potentiality of wheat cultivar mixtures to reduce weed growth and increase the wheat yield under different irrigation regimes, and determine the best row mixture ratio of two wheat cultivars for better weed suppression and higher productivity of wheat. Factors included seven cultivar mixture ratios viz. sole BARI Gom 25, sole BARI Gom 30, 1:2, 2:1, 2:3, 3:2 and 1:1 of BARI Gom 25 to BARI Gom 30, and three water management practices viz. no irrigation, one irrigation at crown root initiation (CRI) stage, and two irrigation at CRI and flowering stages arranged in a split-plot design with three replications. Results clearly indicated that cultivar mixture can improve the competitive ability of wheat plants against weeds and can increase wheat productivity. Both cultivars showed better growth, higher weed suppression and increased yield when grown in mixture irrespective of ratios compared to their monoculture. Based on the combined grain yield, different mixture ratios performed in the order 1:1, 2:3, 1:2 and 2:1 BARI Gom 25 to BARI Gom 30 under two irrigation regimes. BARI Gom 25 and BARI Gom 30 inter-planted in 1:1 row ratio under two irrigation appeared as the best practice resulting 9% and 5.83% yield advantages over sole culture of BARI Gom 25 and BARI Gom 30, respectively; while mixture ratio of 3:2 resulted in 6.43% and 3.36% weed dry matter reduction over sole culture of BARI Gom 25 and BARI Gom 30, respectively. In conclusion, cultivar mixture strategy can be adopted as an effective tool for better weed management and increased yield of wheat. 

Abstract A limiting factor in valerian production is weed interference so, the crop protection from weed is essential. Field experiments were conducted for two consecutive seasons (2014-2015) to evaluate different weed control methods on growth, yield, and oil quality of valerian in Iran. The experimental design was a randomized block with 7 treatment and 4 replicates. Treatments included untreated control, manual weeding, barley straw, sorghum straw, wheat, black plastic and post-emergence oxadiargyl. The lowest density and dry weight of weeds was related to the manual weeding treatment. Result showed that the maximum growth parameters of valerian were obtained from manual weeding treatment followed by black plastic, barely straw and sorghum straw reflecting superior weed control. Essential oil analyses indicated that bornyl acetate, valerenal, camphene and α-pinene were the most abundant constituents. These components on average represent 27.7, 14.7, 4.1 and 2.2% of the oils that were extracted from plant, respectively. Bornyl acetate, valerenal and camphene contents did not vary with the various studied treatments although there was a trend toward higher in manual weeding treatment. Overall finding of current experiments suggested that barely straw and sorghum straw are potential substitutes for manual weeding and black plastic mulch for weed control in valerian.

Abstract 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.

Abstract Eleusine indica population at oil palm estate in the Asahan Regency has never been reported to being resistant to glyphosate and paraquat. This research was aimed to the resistance classification of E. indica population to glyphosate from one of oil palm estate in the Asahan Regency and to find out of glyphosate-resistant Eleusine (GRE) biotype has been also resistant to paraquat. This research was conducted on Weed Research Center Land, Faculty of Agriculture, Universitas Sumatera Utara, Medan from September 2017 until May 2018. Single resistance evaluation of E. indica population was performed using glyphosate at the dose 720 g a.i.ha^-1. However the multiple resistance of GRE biotype was performed using paraquat at rates of 0, 50, 100, 200, and 400 g a.i.ha^-1 and glyphosate at rates of 0, 720, 1440, 2880, and 5760 g a.i.ha^-1. Susceptible-population (ESU-0) was taken at ball field of Politeknik Negeri Medan (Medan City) as a comparison. The data were analyzed by ANOVA and followed by Duncan test at level 5% using IBM SPSS Statistics software. The results showed that E. indica populations from one of oil palm estate in the Asahan Regency had survival of 81.48% (classified as glyphosate-resistant) and the dry weight of 24.35 g. Glyphosate at the dose 2880 g a.i.ha^-1 and paraquat at the dose 200 g a.i.ha^-1 were effectively (100%) controlled survival, tillers.pot^-1, fresh weight.pot^-1, dry weight.pot^-1 and mortality of GRE biotype. The resistance index value of GRE biotype to glyphosate and paraquat of 4.91- and 1.26-fold, respectively compared to susceptible plants.

Abstract Microbes and their secondary metabolites offer a benign and eco-friendly alternative to manage weed. Mycoherbicide production for biological control of weeds requires a series steps, from selection of a suitable microbial strain to final formulation. Thus, this study aimed to select potential fungi for production of secondary metabolites with herbicidal activity for control of Parthenium weed. In the present study, phytopathogenic fungi namely Fusarium spp. were isolated from infected tissues of Parthenium and evaluated against Parthenium hysterophorus, a problematic monocotyledonous weed of open lands, Agriculture, Horticulture and Forests. Herbicidal potential of Cell Free Culture Filtrate (CFCF) of three strains of Fusarium spp. coded as FGCCW#16, FGCCW#43 and FGCCW#55, against Parthenium hysterophorus were evaluated by seedling and shoot cut bioassays.  Maximum mortalities of shoots, seedlings and phytotoxic damage were obtained from 21 days old cell free culture filtrate (CFCF) of FGCCW#16 at 100% concentration. Significant reduction in biological contents i.e. photosynthetic pigment and protein was observed in the host weed on treatment with the CFCF as determined by detached leaf bioassay. Phytotoxic damage such as severe wilting, chlorosis, necrosis and complete collapse of the entire parts of the weed were also noticed due to CFCF application.

Abstract A field experiments was conducted at Professor Jayashankar Telangana State Agricultural University, Rajendranagar during kharif 2017 for the evaluation of diuron in two different soils. The treatments consisted of diuron 80% WP at 0.5, 0.75 and 1.0 kg ha^-1 along with registered formulation of pendimethalin 38.7% CS at 677 g ha^-1, intercropping with green manure crop, mechanical weeding thrice at 20, 40, 60 days after sowing and unweeded control. The experiment was carried out in a randomised block design replicated thrice. The weed flora of the experimental field in red soil was dominated by Cynodon dactylon, Rottboellia exaltata, Parthenium hysterophorus, Trianthema portulacastrum and Commelina benghalensis. While in case of black soil predominant flora was Cynodon dactylon, Cyperus rotundus, Parthenium hysterophorus, Euphorbia geniculata, Tridax procumbens, Cyanotis cristata, Digera arvensis and Celosia argentea. The macronutrient contents in cotton crop were higher in polymulch, mechanical weeding thrice at 20, 40 and 60 DAS and this was comparable to pre emergence application diuron at 1.0 kg ha^-1 followed by post emergence application of pyrithiobac sodium + quizalofop p ethyl in red soil and post emergence application diuron at 1.0 kg ha^-1 followed by post emergence application of pyrithiobac sodium + quizalofop p ethyl and diuron at 0.75 kg ha^-1 black soil. The minimum weed competition facilitated higher DMP and nutrient uptake by the plant. The nutrient removal by weeds also was minimal in polymulch, mechanical weeding thrice at 20, 40, 60 DAS, diuron at 1.0 kg ha^-1 pre emergence application of pyrithiobac sodium + quizalofop p ethyl followed by post emergence application of diuron at 0.75 kg ha^-1 in both red and black soil.

Abstract Echinochloa colona (L) Link. is a problematic annual grass weed in summer fallows in northern Australian cropping regions where repeated use of glyphosate has resulted in the evolution of glyphosate resistance. Pot trials conducted on E. colona populations collected from northern Australia identified 34 glyphosate resistant populations out of 65 populations tested, with resistance levels varying between 2 and 11-fold. The technique of AFLP (amplified fragment length polymorphism) was used to investigate genetic diversity within and between two resistant and one susceptible population. Within these three populations, a total of 354 fragments were identified with 99.2% being polymorphic. The frequency of polymorphic fragments within the 30 individuals from each of the two resistant populations (81.0 and 83.9%) was similar to the susceptible population (80.8%), suggesting no apparent selection bottleneck associated with resistance evolution. The large genetic diversity present within populations suggests a significant level of outcrossing between individuals. A high level of genetic diversity among the individuals was identified across a single individual examined from each of 62 populations. These individuals clustered into four main groups with three isolated accessions. Individuals did not cluster geographically; additionally, individuals did not cluster by resistance or susceptibility to glyphosate either. The results of this study suggest glyphosate resistance evolved independently across a wide geographical region in northern Australia and the large genetic diversity within populations likely contributed to rapid resistance evolution.

Abstract Parthenium hysterophorus weeds are one of the major problems in almost all types of agricultural lands, forest lands, pastures, farmlands and disturbed land including roadsides. It is also responsible for health problems in human and animals besides loss to agriculture and ecosystems. It causes allergic respiratory problems, contact dermatitis and mutagenicity. The main strategy of Parthenium control is the use of chemical herbicides. The increasing side effects of chemical herbicide and growing resistance against them in weeds have attracted the attention of researchers to search for some novel herbicidal compounds from natural sources. A significant barrier in the mycoherbicide metabolites production is the development of an economically viable fermentation process. The production of these compounds is largely affected by certain parameters like pH, temperature, incubation days and media constituents etc. Adjustment of these parameters up to optimum level leads to maximum production of mycoherbicidal compounds. Therefore, the purpose of this study was to standardize physiochemical conditions (Nutrient media, pH, Temperature, and Incubation periods) for maximum production of mycoherbicidal metabolites from phytopathogenic fungi Fusarium sp. FGCCW#16 isolated from Parthenium hysterophorus weed. Fusarium sp FGCCW#16 grew well and produced optimum mycoherbicidal metabolites in Richard’s broth medium at 25 to 28°C on the 21 studay of the incubation. The optimal growth, however, was obtained at pH 6. The results of this investigation indicated that cultural conditions like culture media as well as physical factors such as temperature, pH and incubation period greatly affected the growth and production of mycoherbicidal metabolites by Fusarium sp FGCCW#16.

Abstract Herbicide efficacy could be enhanced by herbicide combinations and addition of surfactants. These substances improve absorption of herbicides by lowering the surface tension of spray droplets resulting in increased area of contact of the herbicide solution with the leaf surface. This experiment determined the tolerance of rice and efficacy of three post-emergence herbicides in varying combinations with surfactants against Echinochloa crus-galli (L.) Beauv., Cyperus iria L., and Ludwigia octovalvis (Jacq) Raven. The study was conducted at the Cambodian Agricultural Research and Development Institute (CARDI), in Cambodia from January to February 2019. Rice at 10 days after herbicide application (DAHA) showed some degree of susceptibility to Pyribenzoxim- and Quinclorac 50%+ Pyrazosulfuron-ethyl 7% + Fenoxaprop-P-ethyl 13% pre-mix-surfactant mixture but was fully recovered at 20 DAHA. Generally, rice was more tolerant at the 4-6 than at the 2-3 leaf stage. Phytotoxicity of the herbicides to Echinochloa crus-galli depended on the herbicide and surfactant concentration and the stage of growth of the weed at application time. Cyperus iria and Ludwigia octovalvis were relatively more sensitive to the pre-mix alone and where, in most instances, did not merit addition of surfactant.