Tarundeep Kaur

Mulching and herbicides in peach: Weed biomass, fruit yield, size, and quality

An experiment was conducted to study the effect of mulches and herbicides on weed population, fruit yield, and quality in peach cv. ‘Earli Grande.’ Covering soil with black polythene mulch (100 μm) resulted in 100% control of weeds at six weeks after treatment (WAT) during both the years of study. However, guinea grass, which had emerged out of the black polythene mulch, reduced the weed control efficiencies (WCE) to 96.3 and 98.5% in 2009 and 2010, respectively, at 12 WAT. Application of straw mulch (8 cm, 15.5 t ha− 1) resulted in higher weed control efficiencies at 6 WAT during 2009 and 2010 (98.4 and 98.2%, respectively). At 12 WAT, this decreased to 90.7 and 93.1% in 2009 and 2010, respectively, due to the emergence of bermuda grass and guinea grass from the mulch. The weed control efficiencies with treatments having diuron as pre-emergence herbicide did not differ significantly from black polythene at 6 WAT. Atrazine and pendimethalin were the next most efficient and did not differ significantly from each other. At 12 WAT, diuron followed by fb glyphosate resulted in higher WCE, and it did not differ significantly from atrazine fb glyphosate. In both years, highest fruit yield (69.3 and 67.9 kg tree− 1, respectively) was recorded with straw mulch (8 cm). Straw mulch (8 cm) also resulted in a 20 and 19% increase in fruit weight (81.9 and 81.4 g during 2009 and 2010, respectively) over manual weeding. Straw mulch (8 cm) did not differ significantly from straw mulch (6 cm), black polythene mulch, and diuron treatments for fruit yield during both years. Conclusively, plastic and straw mulches can be used as an effective chemical-free alternative to manual or chemical weed control in peach.

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.

Ecological Methods for Weed Management

Weed ecology is influenced by the plant community composition, the evolution of weeds, allelopathy and competition. Climatic, edaphic and biotic factors determine the distribution of weed species, their type, prevalence and intricate relationships resulting in association of weeds whose ecological requirements tally with the crop. Environmental factors such as temperature, osmotic potential, pH, salinity, light, burial depth and management practices affect seed germination and emergence of weeds. These factors are important for the development of integrated weed control strategies. We review ecological weed association, germination ecology of weeds, crop-weed competition, weed flora in different crops and ecological approaches for weed management. We discuss shifting the focus from weed control to weed management and how the integration of cultural, mechanical and chemical practices can reduce weed establishment. Weeds reduce crop yield by competition for light, water, nutrients and space, interfering with harvesting operations and increasing the cost involved in crop production. Cultural practices can be manipulated for eliminating or reducing the population of major weeds. Overall, knowledge of weed ecology can be used as a tool for effective weed management.

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.