Simerjeet Kaur

Development of cross resistance in isoproturon resistant Phalaris minor Retz. in Punjab

Seeds of isoproturon resistant Phalaris minor were collected from wheat fields and field experiments were conducted during winter season of 2012 and 2013. The biotype was found resistant to clodinafop-propargyl, fenoxaprop-pethyl and also showed cross resistance to pinoxaden. Mesosulfuron + iodosulfuron and sulfosulfuron provided 65 and 90 per cent control of the weed, respectively. Metribuzin recorded above 90 per cent weed control during both the years. Plants sprayed with metribuzin showed a sharp decrease in chlorophyll fluorescence (Fv/Fm ratio) of about 65 per cent as compared to control after 24 hours of spray even when there were no visible symptoms of herbicide injury. By this time, reduction in Fv/Fm ratio was less than 10 per cent for plants treated with ACCase and ALS inhibitors. At 15 days after spray, Fv/Fm ratio decreased by 11 to 13 and 23 to 30 per cent as compared to control for ACCase and ALS inhibitors, respectively.

Appearance of new weeds in Punjab

Weed monitoring and survey was conducted to detect appearance of new weed species. Ten new weed species namely Galium spurium Linn. (family Rubiaceae), Geranium nepalense Sweet (family Geraniaceae), Lamium amplexicaule Linn. (family Lamiaceae), Evolvulus nummularius (family Convolvulaceae), Euphorbia thymifolia Linn.(family Euphorbiaceae), Oenothera laciniata Hill (family Onagraceae), Soliva anthemifolia (Juss.) R. Brown (family Asteraceae), Verbesina encelioides (Cav.) Benth. and Hook. f. ex A. Gray (family Asteraceae), Nicotiana plumbaginifolia Viv. (family Solanaceae) and Portulaca oleracea L. (family Portulacaceae) have been recorded in the last decade from different places of Punjab State. Out of these, weed species namely, O. laciniata, L. amplexicaule, S. anthemifolia and G. nepalense were mainly observed inhabiting the crop fields. Three weed species namely, G. spurium, N. plumbaginifolia and V. encelioides were observed growing along roadsides, wastelands, canal banks and uncultivated areas. P. oleracea and E. thymifolia were observed growing on bunds of agricultural fields. E. nummularius is a serious weed of lawns and landscapes. These weeds have now domesticated in the studied ecological niche and may potentially harm the biodiversity of those areas.

Control of canarygrass in wheat with pre-mixture of pinoxaden plus clodinafop-propargyl

The field efficacy of pre-mixture of pinoxaden plus clodinafop for control of Phalaris minor Retz. in wheat was evaluated in winter 2011-12 and 2012-13 on Research Farm, Department of Agronomy at Punjab Agricultural University, Ludhiana. The study comprised of pre-mixture of pinoxaden plus clodinafop 40, 50 and 60 g/ha, clodinafop 60 g/ha, pinoxaden 50 g/ha and unsprayed control. The results revealed that post-emergence application of pre-mixture of pinoxaden plus clodinafop at 50-60 g/ha recorded effective control of P. minor and recorded the highest effective tillers/m2, spike length and wheat grain yield and was significantly better than its application at 40 g/ha and clodinafop during both the years and pinoxaden alone in one year.

Control of mixed weed flora in wheat with sequential application of pre-and post-emergence herbicides

The field efficacy of pre-and post-emergence herbicides for control of mixed weed flora in wheat was evaluated in a field study conducted at Punjab Agricultural University, Ludhiana during Rabi seasons of 2014–15 and 2015–16. The season long growth of weeds reduced wheat yield upto 38.5%. Pendimethalin and metribuzin recorded 65–73 and 73–78% control of Phalaris minor, respectively and their tank-mix application enhanced P. minor control to 78–85%. Pendimethalin and metribuzin recorded 26–33 and 5863% control of Medicago denticulata, respectively and their tank-mix application enhanced control to 77–92% of this weed. Pendimethalin and metribuzin provided control of Rumex dentatus to the extent of 98–100% and 68–92%, respectively, while provided 98–100 and 63–72%, respectively control of C. album. Sequential application of pendimethalin as pre-emergence followed by sulfosulfuron as post-emergence recorded the highest weed control efficiency (96%) and wheat grain yield (4.8 t/ha), and it was at par to pre-emergence pendimethalin + metribuzin, post-emergence pinoxaden + metsulfuron, mesosulfuron + iodosulfuron, sulfosulfuron + metsulfuron and two hand weeding.

Weed control in conventional soybean with pendimethalin followed by imazethapyr + imazamox/quizalofop-p-ethyl

Abstract: The objectives of this study were to evaluate the efficacy of pendimethalin applied pre-emergence (PRE) followed by post-emergence (POST) application of imazethapyr + imazamox/quizalofop-p-ethyl for weed control and their effect on conventional soybean injury, yield attributes, and yield. Field experiments were conducted in 2013 and 2014 in conventional soybean. Herbicide treatments provided ≥90%, 70%, and 85% control of crowfoot grass, large crabgrass, and goosegrass, respectively, and ≤80% control of false amaranth and horse purslane at 30 d after sowing (DAS). At 60 DAS, pendimethalin applied alone or followed by hand-hoeing/quizalofop-p-ethyl/imazethapyr + imazamox provided 100% control of goosegrass and 65%–100% control of crowfoot grass/large crabgrass. Pendimethalin followed by imazethapyr + imazamox/quizalofop-p-ethyl as well as quizalofop-p-ethyl applied alone resulted in complete control of crowfoot grass, large crabgrass, and goosegrass, but control of broadleaf weeds was variable. Pendimethalin followed by imazethapyr + imazamox at 70 g ha-1 at 28 DAS, imazethapyr + imazamox at 60 or 70 g ha-1 at 21 DAS followed by quizalofop-p-ethyl at 37.5 g ha-1 at 42 DAS resulted in soybean branch numbers per plant, number of pods per plant, and soybean seed yield comparable to weed-free control. Control of Benghal dayflower and purple nutsedge was not acceptable.

Effectiveness of new herbicides in management of broadleaf weeds and sedges in transplanted rice

A study was planned to evaluate efectiveness of new pre-mix herbicide metsulfuron methyl+chlorimuron ethyl for management of sedges and broadleaf weeds in transplanted rice at research farm of Punjab Agricultural University, Ludhiana for three years. The treatments comprised of metsulfuron methyl+chlorimuron ethyl 3, 4 and 5g/ha, azimsulfuron 20g/ha and metsulfuron 4 g/ha as post emergence and unsprayed control, replicated four times. The results indicated that the density and biomass of sedges and broadleaf weeds was signifcantly less in metsulfuron methyl+chlorimuron ethyl 4 and 5g/ha than 3g/ha, azimsulfuron 20g/ha, metsulfuron 4g/ha and unsprayed control. Application of metsulfuron methyl+chlorimuron ethyl 4g/ha applied in rice recorded signifcantly highest average grain yield of 7.31t/ha. There was a negative linear relationship between weed biomass and grain yield (r=-24.08). Correlation matrix revealed that all the yield attributes showed higher correlation with metsulfuron methyl+chlorimuron ethyl 4g/ha. Post emergence application of metsulfuron methyl+chlorimuron ethyl at 4g/ha resulted in efective control of broadleaf weeds and sedges in transplanted rice.

Herbicides combinations for control of complex weed flora in transplanted rice

The puddled transplanted rice is infested with mix of grasses, sedges and broad-leaf weeds in Northern India. For control of mixed weed flora, different herbicide combinations were evaluated in a field experiment conducted in summer of 2012 and 2013 at Ludhiana. The experimental field was infested with Echinochloa spp., Ischaemum rugosum, Caesulia axillaris, Cyperus iria and Ammania baccifera. The performance of preor early post-emergence herbicides applied alone was poorer during 2012 (dry year). The differential rainfall during both the years influenced the efficacy of herbicides. The herbicide treatments integrated with hand weeding recorded good weed control during both the years. Preemergence application of pyrazosulfuron-ethyl at 20 g/ha + one hand weeding or bispyribac-sodium 25 g/ha applied as alone or as tank-mix with ethoxysulfuron 18.7 g/ha recorded the highest weed control efficacy, rice grain yield and net returns during both the years and seemed to be the best ways of controlling complex weed flora and enhancing productivity and profitability from transplanted rice.

Management of complex weed flora in maize with post-emergence herbicides

Some weed species are not controlled by atrazine where the farmers are using this herbicide year after year and different flushes of weeds in rainy season are among the major problems in maize growing areas of India. A field experiment was conducted during the crop growing seasons of 2012 and 2013 at Research Farm, Department of Agronomy, Punjab Agricultural University, Ludhiana to evaluate the efficacy of glyphosate 41% SL against complex weed flora in maize. The treatments included glyphosate 41% SL 900, 1800 and 3600 g/ha applied as post-emergence at 2-4 leaf stage of weeds, atrazine 750 g/ha as preemergence, paraquat 24 SL 500 g/ha as post-emergence at 2-4 leaf stage of weeds, 2,4-D sodium salt 1000 g/ha as post-emergence at 2-4 leaf stage of weeds, weed free and unweeded control. The results revealed that non-selective herbicides paraquat at 500 g/ha and glyphosate at 900 and 1800 g/ha as a directed spray in maize as post-emergence at 2-4 leaf stage of weeds recorded effective control of grass and broad-leaf weeds during both the years and recorded grain yield at par with atrazine.

Efficacy of different clodinafop-propargyl formulations against littleseed canarygrass in wheat

Field experiments were conducted in three successive seasons (Rabi 2010–11, 2011–12 and 2012–13) to evaluate the efficacy of clodinafop-propargyl formulations (wettable powder and emulsifiable concentrate) applied as post-emergence against Phalaris minor in wheat crop. All formulations of herbicide reduced the density of Phalaris minor over the weedy check however treated plots yielded below than the state average yield of wheat crop. These new clodinafop formulations/brands failed to provide effective control of resistant P. minor prevailing in wheat field during all years, and gave only 2732% control of Phalaris minor over the weedy check. These new formulations also yielded similar to clodinafop-p-propargyl applied as standard check. Per cent control of Phalaris minor was found to be reduced from 60 to 40% over unsprayed check with delay in application time of clodinafop from 35 to 60 DAS.

Imidazolinone herbicides for weed control in greengram

A field experiment to study the efficacy of imidazolinone herbicides in greengram was conducted during Kharif seasons of 2012 and 2013. Ten weed control treatments viz. imazethapyr at 50 and 70 g, premix of imazethapyr + imazamox at 60 and 70 g/ha, both applied as post-emergence at 20 days after sowing; pendimethalin 1000 g and premix of pendimethalin + imazethapyr at 800, 900, 1000 g/ha, both applied as pre-emergence, along with two hand weedings and weedy check were evaluated. Imazethapyr alone and its premixes with pendimethalin and imazamox recorded effective control of mixed weed flora and produced significantly higher greengram seed yield than weedy check. Pendimethalin alone did not control Commelina benghalensis and recorded lower seed yield. All the herbicides were safe to crop.