Journal of Research in Weed Science

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.

Abstract A two-year (2017 and 2018) field trials was conducted in the School of Agriculture, Njala University, Sierra Leone, to evaluate weed management practices on weed dynamics and productivity of maize. The experimental trials were laid out in a randomized complete block design (RCBD) with three replications. The treatment combinations comprised of weedy check (Control), two hoe weeding at 4 and 8 weeks after planting (WAP), Double force^® at 4 L ha^-1 plus one hoe weeding at 8 WAP, Gliricidia sepium leaves mulch at 40 kg m^-2 plus one hoe weeding at 8 WAP, weed-free check and Atrazine 500 SC at 3 L ha^-1 plus one hoe weeding at 8 WAP. The results showed that growth and yield physiognomies differ significantly (P<0.05) among weed control practices across both years. The weed-free check treatment recorded the highest growth and yield physiognomies with respect to reduced weed density and increased weed control efficiency followed by herbicidal treatments, while weedy check had the lowest growth and yield attributes across both years. Nonetheless weed-free check required lot of labour force which was not economical to the farmer’s point of judgment. Thus, Double force^® at 4 L ha^-1 plus one hoe weeding at 8 WAP proved to be better in controlling weeds, increasing crop yield and economical compared with other weed management practices. Hence Double force^® at 4 L ha^-1 plus one hoe weeding at 8 WAP was recommended as a pre-emergence herbicide in maize production for effective and environmentally friendly weed control method.

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 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 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 In modern agriculture, use of herbicides has become indispensable for managing weeds in cultivated lands, due to the scarcity of labors in almost all parts of the globe. Herbicides provide effective weed control in agriculture, yet their continuous and excessive use may pose serious health and environment threats. Pendimethalin is proved to be a very effective pre-emergence herbicide for the control of annual weeds in leguminous and other vegetable crops. Therefore bio-efficacy and residues of pendimethalin were determined in chickpea (Cicer arietinum L.) crop at farmers’ field. Pendimethalin was applied at 796 g ha-1 as a pre-emergence herbicide to control weeds in chickpea fields. Pendimethalin was found effective against weeds viz. Vicia sativa, Convolvulus arvensis, Chenopodium album, and Lathyrus sativa. Terminal residues of pendimethalin were found below