Journal of Research in Weed Science
Volume:2 Issue: 1, Mar 2019

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.

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.

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.

An experiment was conducted in IAAS, Lamjung research field in 2017 in spring Maize with split plot design to evaluate the effect of weed management practice and tillage system on productivity of spring maize. In tillage system, no-till and conventional tillage were kept as main factor whereas seven weed management practices (viz. sequential application of atrazine at 0.75 kg a.i. ha-1 and 2,4-D at 1.5 kg ha-1; pre-emergence tank mix application of atrazine at 0.75 kg ha-1 and glyphosate at 2.5ml lit-1 of water; pre-emergence tank mix application of atrazine at 0.75 kg ha-1 and pendimethalin at 2ml lit-1 of water; cowpea co-culture; black polythene mulch with control treatment weed free and weedy check as sub-plot. Tillage method had not significant effect on the weed dry matter accumulation in different stages. However, weed dry matter accumulation was varied with different weed management practices. The weed check plot was of highest dry matter accumulation (273.38g m-2, 361.95 g m-2 and 235.95 g m-2 in three different stages (30, 60 and 90 DAS respectively). The highest grain, straw yield and yield attributes was found in plastic mulch plot and no-till system with less severe to weed infestation and index which is statically at par with intercropping with cowpea. Though none of weed management practices completely eliminated weeds, black polythene mulching resulted in best grain yield. Besides the environmental protection, cowpea co-culture treatments yielded almost similar grain yield as compared with common herbicidal weed management practices.

The experiment was carried out at Umulolo in Okigwe Imo State in 2016 and 2017 seasons. The experiment was laid in randomized complete block design, replicated three times. The treatments were mulching materials (two synthetic materials-polythene sheet, trampoline sheet) while natural or organic materials were 6/ha sawdust and grasses and control treatment (no mulching). Result showed significant difference in all the weed infestation parameters, vegetative growth and yield parameters assessed. In both cropping seasons, the control had significant higher weed density and biomass. Garden egg fruit yield as influenced by different mulching materials was also significantly different (p<0.05) in both cropping seasons. The highest fruit yield; 22.27 and 23.63 t/ha in 2016 and 2017, respectively was from the plot mulched with sawdust. The grasses mulched plot had 21.19 and 22.17 t/ha fruit yield, respectively. The trampoline plot produced 18.77 and 17.18 t/ha fruit, respectively. The least fruit yield was 5.43 and 6.54 t/ha in both cropping seasons in control treatment. The result showed that the plot mulched with sawdust had 7-76% and 6-72% greater fruit yield compared to the other mulching materials in both cropping seasons. The result of indicated that application of grasses and sawdust were more cost effective in weed management and higher economic returns to management compared to trampoline and polythene sheets. Farmers in the study area were advised to mulch their garden egg field during off-season with sawdust. The application of sawdust would reduce weed infestation and also enhances high fruit yield.

Sustainable agriculture requires the use of environmentally friendly management practices. Mulching is one of the most effective methods that can play a positive role in weed management, improving soil properties as well as increasing crop production. A field experiment was conducted at the research farm of National Maize Research Program (NMRP), Rampur, Chitwan, Nepal during winter season, 2016. The experiment was carried out in single factor randomized completely block design comprising of nine weed management methods with four replications. Data regarding the weed population, weed dry weight, yield attributes and yield were recorded during the study. Different weed management practices showed significant differences on weed dynamics and weed control efficiencies. Black polythene mulch and silver black mulch was found more effective to reduce total weed density and dry weight during whole crop season and remain comparable with other polythene mulch too. The effect of weed management practices observed on weed density and dry weight were reflected on grain yield. The highest grain yield was recorded in silver black plastic mulch (4537.50 kg ha-1) followed by black plastic mulch (4068.20 kg ha-1), clear plastic mulch (4065.22 kg ha-1), green plastic mulch (3834.84 kg ha-1) and weed free (3222.74 kg ha-1) which were comparable to each other. At tasseling-silking stage among plastic mulch treatment, the higher moisture conservation observed on the black plastic mulch followed by clear plastic mulch, green plastic mulch and silver black plastic mulch. While comparing of plastic mulch with dead mulch, moisture on dead mulch remain higher than plastic mulch after 90 DAS. Thus, in humid subtropical region of western Chitwan, Rampur, the maize can be successfully cultivated by using different color of polythene mulch.

A field study was conducted at Dr. Balasdaheb Sawant Konkan Krishi Vidyapeeth, Dapoli (Maharashtra) during Kharif seasons (2011 to 2014) on rice crop to evaluate the effect of green manuring with Sesbania rostrata and different herbicides on complex weed flora in transplanted rice. The experimental field was infested with Ludwigia octovalis, Cloem viscosa, Cyperus iria, Amaranthus sessils, Isachne globosa and Eriocaulon hexangularis. Application of pre-emergence fixed herbicide and pre-emergence and post-emergence rotational herbicides reduced the complex weed flora. Pre-emergence application of pretilachlor-S at the rate of 0.75 kg/ha at 3-7 days after treatment (DAT) recorded the highest weed control efficiency, rice grain yield and net returns during all years is the best ways of controlling complex weed flora and enhancing productivity and profitability from transplanted rice.