Trifloxysulfuron (CGA-362622) at 2.5, 5 and 10 g a. i./ha mixed with non-ionic (0.25% Induce and X-77), organosilicone (0.1% Kinetic and Silwet L-77) and crop oil concentrate (1.0 % Agridex and Meth-N-Oil) adjuvants was evaluated for bioefficacy, surface tension, contact angle and chlorophyll fluorescence responses in guineagrass (Panicum maximum L.), sicklepod (Senna obtusifolia L.), yellow nutsedge (Cyperus esculentus L.) and cotton (Gossypium hirsutum L.). The lowest surface tension and contact angle were recorded with L-77 mixed with trifloxysulfuron. Among the six adjuvants, surface tension and contact angle were highest with Meth-N-Oil; however, these differences did not greatly influence herbicide efficacy. Decreasing or increasing the adjuvant concentrations from 1X to 0.5 or 4X with 10 g/ha trifloxysulfuron had only 2 to 4% variations in surface tension and contact angle compared to recommended rates (X) when data were averaged over adjuvants and concentrations. Adjuvants had no antagonistic effects for trifloxysulfuron activity on any weed species. Phytotoxicity symptoms of trifloxysulfuron on cotton disappeared after two weeks, but plant height and fresh weight were reduced 3 WAT compared to control plants. Reduction in plant height or fresh weight of cotton was similar for different adjuvants mixed with trifloxysulfuron. Guineagrass was less affected by trifloxysulfuron plus adjuvants than yellow nutsedge or sicklepod. Kinetic mixed with trifloxysulfuron was more effective in reducing plant height and fresh weight of guineagrass compared to other adjuvants; however, activities were comparable when data averaged over species and rates for different adjuvants. Chlorophyll fluorescence was reduced in all the species after herbicide application, but the reduction was not consistent with application rates, species and duration of 1, 4, 7 and 14 days after treatment (DAT). Reduction in chlorophyll fluorescence in treated plants of cotton was less than weeds, but followed no particular trend with herbicide rates or adjuvant interaction. Visual mortality of 17, 53 and 36% at 2 WAT in guineagrass, sicklepod and yellow nutsedge, respectively, was not visible in similar reduction in chlorophyll fluorescence, when data were averaged over treatments. Chlorophyll fluorescence may not be an ideal tool to predict herbicidal efficacy of trifloxysulfuron in the test species.

Thorough land preparation and irrigation upto field capacity for solarization was found effective in suppressing weeds and increasing the yield of baby corn followed by one ploughing + harrowing and 40 mm of irrigation. The combination of these treatments with one hand weeding at 30 days was crucial in suppressing the weeds and enhancing the productivity in succeeding crop of groundnut

An experiment was conducted on the Research Farm of the Department of Agronomy, Agrometeorology and Forestry, PAU, Ludhiana, during 2005 and 2006 in order to find out effective weed management methods for controlling hardy weeds of maize crop such as Acrachne racemosa, Commelina benghalensis and Brachiaria reptans, etc. During 2005, all the weed control treatments except alone application of pendimethalin 1.0 kg/ha and alachlor 2.5 kg/ha produced significantly higher grain yield and less dry matter accumulation by weeds as compared to the recommended herbicide i. e. atrazine 1.0 kg/ha. During 2006, tank mix application of atrazine 0.75 kg+ pendimethalin 0.50 kg/haproduced significantly higher grain yield as compared to recommended herbicidal treatment. On the basis of mean values, it may be concluded that tank mix application of atrazine 0.75 kg + pendimethalin 0.75 kg/ha, atrazine 0.75 kg + alachlor 1.25 kg/ha and atrazine 0.75 kg + trifluralin 1.2 kg/haincreased grain yield of maize by 48.3, 53.9 and 49.7% over unweeded control. Also integration of HW with pre-emergence application of atrazine 0.75 kg/ha, atrazine 0.50 kg + pendimethalin 0.50 kg/ha, atrazine 0.50 kg + alachlor 0.75 kg/ha and atrazine 0.5 kg + trifluralin 0.60 kg/ha produced significantly higher grain yield and less dry matter accumulation by weeds than pre-emergence application of atrazine 1.0 kg/ha and all these treatments increased grain yield by 68.4, 71.6, 64.6 and 68.9% over unweeded control and 14.7, 17.0,1 2.2 and 15.2% than atrazine 1.0 kg/ha.

A field experiment was conducted at Crop Research Farm, Department of Agronomy A. A. I (DU), Allahabad during 2002 on winter maize to assess the relationship amongst weed parameters, yield attributes and yield under the influence of different weed management practices. Grain yield of winter maize showed a significant positive correlation with WCE, number of cobs and cob length. On the contrary, these parameters were negatively correlated with the population and biomass of weeds at 60 DAS. A unit increase in weed population and weed biomass/m2 estimated reduction in grain yield by 0.79 and 1.418 q/ha, respectively. Similarly, the increase in the grain yield due to a unit increase in WCE (%) was estimated at 0.575 q/ha.

A field experiment was conducted during rainy (kharif) seasons of 2005 and 2006 at Jabalpur to assess the efficacy of penoxsulam as pre-emergence (5 days after transplanting–DAT) and early post-emergence (10 DAT) in transplanted rice (Oryza sativa L.). The major weeds were Echinochloa colona, Cyperus spp., Ammania baccifera, Lindernia crustacea, Eriocaulon spp., Caesulia axillaris, Alternanthera sessilis and Commelina spp. Infestation of weeds reduced grain yield of rice by 25.9%. Penoxsulam 22.5 g/ha applied at 10 days after transplanting was found most effective in controlling weeds and maximizing rice grain yield (6287 kg/ha). Early post-emergence application (10 DAT) of penoxsulam was better than its pre-emergence application (5 DAT) in increasing grain yield. Grain yield of rice was significantly and negatively correlated (r = -0.82) with weed dry matter.

A field experiment was conducted at CCSHAU Rice Research Station, Kaul during kharif (rainy) seasons of 2006 and 2007 to evaluate the efficacy of new herbicide penoxsulam with different rates and time of application in transplanted rice. Weeds caused 30 to 32% loss in grain yield in weedy check as compared to weed free treatment. Higher doses of penoxsulam i. e. 0.0250 kg/ha (1-5 DAT) and 0.0225 kg/ha (8-12 DAT), while at par with each other and also with hand weeding twice (20 and 40 DAT), proved significantly better in controlling grassy, sedges and broadleaf weeds and provided significantly higher grain yield (similar to hand weeding and weed free treatments) and higher weed control efficiency than the standard herbicide butachlor at 1.5 kg/ha (1-3 DAT). The lower doses of penoxsulam i. e. 0.0225 kg/ha (1-5 DAT) and 0.0200 kg/ha (8-12 DAT) were, however, similar to butachlor. The study also revealed that comparatively lower doses of the herbicide could be used when it was applied at early post emergence (8-12 DAT).

An experiment was conducted during the rainy seasons of 2003 and 2004 at Agronomy Research Farm, Allahabad Agricultural Institute-Deemed University to assess the response of rice and associated weeds to establishment methods, fertility levels and weed management practices. The experiment was laid out in three factor randomized block design comprising two establishment methods (direct wet seeding and transplanting), three levels of fertility viz., 80, 40, 40; 100, 50, 50 and 120, 60, 60 NPK kg/ha and four weed management practices viz., (W1) anilofos @ 0.4 kg a. i./ha, (W2) butachlor @1.5 kg a. i./ha, (W3) two hand weedings and (W4) weedy check. These comprised 24 treatments, which were replicated thrice. Results revealed that transplanting method of rice establishment recorded lowest number of weeds and weed dry weight resulting in significantly higher grain yield. The weed intensity and weed dry weight increased with the increase in fertility level and was maximum with 120, 60, 60 NPK kg/ha. Anilofos and butachlor brought down weed intensity, weed dry weight and NPK uptake but were not as efficient as two hand weedings. The higher net profit and BCR was observed in direct seeded plots treated with high fertilizer dose of 120, 60, 60 NPK kg/ha and anilofos. The maximum weed control efficiency was observed in transplating between establishment methods, low fertilizer dose of 80, 40, 40 NPK kg/ha between fertility levels and anilofosn among weed management practices at all the growth stages of crop. The maximum weed index of 68% was observed in weedy check plots.

Field and pot experiments were conducted to study the persistence of pyrazosulfuron-ethyl in soil. In pot experiment, maize, soybean, moong and sorghum were grown in succession upto three sowings at 21 days intervals at different concentrations of herbicide ranging from 0 to 0.2 ppm. Germination count, shoot height and dry weight of crops were drastically reduced at higher concentrations of herbicides in first sowing. However, in the second and third sowings differences for plant height and dry weight were less at different concentrations of herbicide indicating degradation of herbicide to safe levels. In field experiment residual carry over effects of pyrazosulfuron-ethyl applied in rice at 15 and 30 g/ha were studied using wheat, gram and pea as indicator plants. Differences were non-significant for dry matter accumulation in these plants, indicating that there was no residual effect of herbicide in soil after the harvest of rice crop.

Field experiment was conducted during 2003 and 2004 in the Research Area of Agronomy Department, CCS Haryana Agricultural University, Hisar to study the effect of irrigation frequency on residual behaviour of sulfosulfuron applied in wheat on succeeding sorghum crop grown in rotation. Residual effect of sulfosulfuron was assessed by conducting bioassay studies on sorghum in a split plot design with three irrigation levels (3, 4 and 5) in the main plots and weed control treatments (sulfosulfuron 25 and 50 g/ha, weedy and weed free) in the sub-plots. After harvest of wheat, sorghum crop was planted after slight disking without disturbing the original layout. Sulfosulfuron applied in wheat was found to persist even after 150 days after its application in wheat and its residues in the soil medium caused phytotoxicity to succeeding crop of sorghum. Plant population, plant height, number of leaves per plant, dry shoot and root weight and fodder yield of sorghum were significantly reduced by sulfosulfuron. At 60 DAS, 50 g sulfosulfuron applied in wheat reduced sorghum plant height, dry shoot and root weight per plant by 56, 50, 70 and 57, 51, 71% during the first and second year, respectively, over untreated control. Similarly, fodder yield was reduced by 73 and 75% by 50 g sulfosulfuron compared to untreated control in first and second year of investigation, respectively. The residual effect of sulfosulfuron on sorghum was not found to be mediated by irrigation frequency. Neither the growth parameters nor the fodder yield of sorghum were affected significantly by number of irrigations applied in wheat. Therefore, it can be inferred that increasing irrigation frequencies neither helped in degradation nor in leaching of sulfosulfuron and sorghum should not be planted in rotation with wheat where sulfosulfuron has been applied in wheat.

Based on two years’ field investigation, it was found that sulfosulfuron at 25 g/ha reduced density and dry weight of total weeds to the extent of more than 70% at different growth stages of wheat. This led to a significant increase in the number of effective tillers, 1000-grain weight and ultimately grain of wheat. However, grain yields of wheat were significantly more in the plots kept weed free throughout the crop season. Among 10 wheat cultivars, PBW 343, WH 542 and HD 2687 being at par with each other proved more competitive against weeds and consequently produced more grain yield. Whereas WH 711, WH 533 and Raj 3765 turned out to be poor competitors and lower yielders. On an average, weeds reduced the grain yield of wheat to the tune of 22% over the years.

DMA by Phalaris minor and BLB was significantly more in unsprayed control than all other herbicide treatments. On an average, the per cent reduction in dry matter of P. minor varied from 26.19 to 30.69 in herbicide treatments over unweeded control at harvest. Increase in the dose of sulfosulfuron and mesosulfuron+iodosulfuron reduced dry weight of weeds in the decreasing trend over weedy check due to varied concentrations. The studies revealed that all doses of sulfosulfuron (25, 37.5 and 50 q/ha) and mesosulfuron+iodosulfuron (12, 18 and 24 q/ha) were at par with each other in terms of yield of wheat as these herbicides gave an effective kill of weeds.

Field experiments were conducted at the experimental area of Punjab Agricultural University, Ludhiana from 2003-04 to 2005-06 on loamy sand soil. Post-emergence (35-40 DAS) application of triasulfuron at 15 g/ha (with and without 1% surfactant) and 20 g/ha alone as well as carfentrazone-ethyl 20 and 25 g/ha controlled broadleaf weeds in wheat very effectively and produced grain yield at par with the already recommended herbicide i. e. 2,4-D 0.5 kg/ha. On an average of three years, highest grain yield was recoded in plots treated with carfentrazoneethyl 25 g/ha closely f. b. triasulfuron 20 g/ha, triasulfuron 15 g + 1% surfactant and 2, 4-D 0.5 kg/ha and compared to unweeded check these treatments increased wheat grain yield by 57.9, 57.3, 56.2 and 53.7%, respectively.

Field study conducted at experimental farm of Punjab Agricultural University, Ludhiana (India) during rabi seasons of 2004-05 and 2005-06 revealed that nutrient uptake by Phalaris minor as well as broadleaf weeds were significantly reduced with zero till sowing in standing stubbles, zero till sowing after partial burning and bed planting techniques as dry matter accumulation by weeds was significantly less in these treatments as compared to conventional tillage and zero tillage techniques (without stubbles). Post-emergence application of clodinafop 60 g/ ha f. b. 2, 4-D 0.5 kg/ha, sulfosulfuron 25 g/ha and mesosulfuron+iodosulfuron 12.0 g/ha significantly reduced the dry matter accumulation by all weeds and hence significantly reduced uptake of N, P and K by both P. minor and broadleaf weeds, whereas clodinafop 60 g/ha alone reduced dry weight and nutrient uptake of P. minor only as compared to control (unweeded) crop.

A field experiment was conducted during winter seasons of 2000-01 and 2001-02 to study the effect of sowing techniques and weed management on weed dynamics and yield of wheat [Triticum aestivum (L.) emend. Fiori and Paol]. Criss-cross sowing significantly reduced weed dry biomass and produced 19.93% more grain yield than broadcast method of sowing. Weed control treatments significantly reduced weed density and weed dry biomass than weedy check. Among the weed control treatments, sulfosulfuron was found most effective herbicide and it significantly reduced the total weed population and density of Phalaris minor and Avena fatua to the tune of 87.3 and 92.9%, respectively, over control. However, isoproturon 0.75 kg/ha controlled P. minor and A. fatua only to the extent of 67.8 and 78.6%. Hand weeding recorded similar grain yield to that of sulfosulfuron and significantly outyielded isoproturon and 2, 4-D.

Phalaris minor has become the major menace in wheat, as it has developed resistance against isoproturon. The farmers are using costly herbicides, namely, clodinafop and sulfosulfuron. A critical analysis of the data revealed that recommended seed rate, bi-directional and zero till method of sowing are some of the factors whose added returns were higher than added costs from wheat because of low infestation of weeds and increase in wheat productivity. Other factors which led to low infestation of Phalaris minor included light soil, low moisture content at upper layer of soil, early sowing of wheat, closer spacing, use of new herbicides, recommended dose of herbicide, use of flood zet & flat fan nozzles, adequate volume of spray, adoption of PBW 343 variety of wheat, crop rotation (potato, sugarcane, vegetables and berseem crop in previous year), one hoeing after first irrigation and application of gypsum. Wheat growers can be benefited a lot if integrated approach of weed management is followed.

The study on phyto-sociological association of weeds in winter crops viz., brown sarson (Brassica campestris L.), oat and wheat (Triticum aestivum L.) of Kashmir valley was conducted during 2000-01 and 2001- 02 at varying altitudes from 1500 to 2000 MSL. Maximum IVI of Poa annua was noticed in brown sarson (throughout valley) and oat (only in higher belts >1700 MSL). At lower and mid altitudes in oat fields and at high altitudes in wheat fields Ranunculus spp. recorded maximum IVI.Wheat fields (above 1600 MSL) showed maximum IVI of Capsella bursa-pastoris.

A survey of weed flora of potato in north-eastern Haryana conducted during 2004-05 revealed that a total of 23 species were found to infest potato fields, out of which three were grassy, 16 broadleaf weeds and only one sedge Cyperus rotundus. C. album, A. arvensis, P .minor, Poa annua, Rumex retroflexus, Melilotus indica, Polypogon monspliensis, Coronopus didymus and Medicago denticulata were the major weeds of potato in all districts. In Panchkula and Ambala Anagallis arvensis was the most dominant weed with a relative density of 15.8, 13.6 and 19.64%, respectively, while in Kaithal and Panipat, Poa annua dominated weed flora with 48.4 and 35.7% of total weed flora followed by C.album. Malwa parviflora a robust dicotyledonous weed, which was considered to be weed of non-cropped areas, has also shown its presence in Kurukshetra and Kaithal districts. Kharif weeds Trianthema portulacastrum and Digera arvensis were found to infest early sown crop in Kurukshetra, while Portulaca oleracea was recorded in Kaithal and Panipat districts.

The water hyacinth weevils, Neochetina bruchi Hustache and Neochetina eichhorniae Warner were studied for their orientation behaviour towards leaves and their aqueous extracts of 18 agricultural and horticultural crops and the host plant Eichhornia crassipes (water hyacinth) under laboratory conditions with the help of a multi-arm olfactometer. Excess proportion index (EPI) was worked out to know the approaching behaviour of the weevils. Both N. bruchi and N. eichhorniae rejected all the crops tested here and preferred water hyacinth only. The EPI values for the leaves of all the crops tested (except paddy and pomegranate) and their extract treatments were only negative, indicating that the weevils rejected the plants. Positive values were obtained in pomegranate (+0.33) and paddy (+0.11) leaf treatments when N. bruchi and N. eichhorniae were used, respectively. In general, extracts were more deterrent to both the weevil species than leaf treatment.

Classical biological control of water hyacinth using insect agent Neochetina spp. is constrained in many tropical watershed environments with interrupted host range due to seasonal water flow and complete drying of water during the hot summer months. Accordingly, the need for reinforcing the classical bio-control approach with sustainable short term measures has been realized and studies were undertaken to explore the possibility of integrating the insect agents and the plant product of dried leaf powder of Coleus amboinicus/aromaticus in controlling water hyacinth at different growth stages based on discriminate analysis using data on plant height, leaf area and fresh weight. Among the different inoculation loads of insect agents, releasing the insect agents @ three/ plant registered the highest reduction in fresh weight, chlorophyll and N, P, K content with small (I stage) and medium (II stage) growth stages of Eichhornia crassipes. At large growth stage (III stage) of E. crassipes none of the loads of insect agents was effective in reducing the fresh weight and chlorophyll content. Among the different concentrations of plant product, spraying at 25% registered the cent per cent reduction in fresh weight, chlorophyll and least N, P and K content at both the stages I and II of E. crassipes. No insect mortality was observed in any of the treatments compared.

Emulsion concentrate or emulsive water (EW) formulation developed from crystallized product of sesame root exudates showed consistent adverse effect on the germination and growth of prominent weeds found in almost all rabi crops. EW formulation at 240 μg/g of soil not only delayed but also inhibited germination of lambsquarters (Chenopodium album) by 80% followed by scarlet pimpernel (Anagalis arvensis) by 75%, white sweet clover (Melilotus alba) by 65%, corn flurry (Spergula arvensis) by 60%, fumitory (Fumaria parviflora) by 55% and common vetch (Vicia sativa) by 50% over control. At 280 μg/g of soil, maximum inhibition in shoot biomass was observed in case of lambsquarters (86%) followed by fumitory (82%), common vetch (52%), corn flurry (49%), scarlet pimpernel (46%) and white sweet clover (42%) over control. Whereas based on root biomass inhibition, the toxicity trend of formulation was observed on lambasquarter by 89% followed by corn flurry (83%), sweet clover (72%), common vetch (65%), fumitory (63%) and scarlet pimpernel (58%). Based on entire biomass inhibition, it was observed more toxic to lambsquarters (86%) followed by fumitory (79%), common vetch (56%), corn flurry (50%), white sweet clover (49%) and scarlet pimpernel (48%) over control at 280 μg/g concentration.

A set of eight treatments comprising weedy and weed-free conditions upto 30, 60 and 90 days after sowing and upto harvest was evaluated at the experimental farm, Hawalbagh of Vivekananda Parvatiya Krishi Anusandhan Sansthan, Almora during winter (rabi) seasons of 1999-2000 and 2000-01 to find out the critical period of crop-weed competition in gardenpea [Pisum sativum (L.) sub sp. hortense Asch and Graebn]. Weed competition index increased with an increase in duration of weedy condition ranging from 1.4 to 34.7 during winter 1999-2000 and 5.4 to 48.7 during winter 2000-01. On the other hand, increase in weed-free period from sowing to harvest decreased weed competition index to 2.0 from 34.7 during winter 1999-2000 and 3.3 from 48.7 during winter 2000-01. Weed-free condition beyond 60 days after sowing did not bring significant improvement in green pod yield. The highest additional net returns (Rs. 6,374/ha) and additional net returns/rupee invested (0.64) were recorded where the plots were kept weed-free upto 60 days after sowing. The critical period for crop-weed competition was observed to be between 30-60 days after sowing when the crop should be kept free from weeds to prevent the potential yield loss and to economize weeding in gardenpea.

A study was conducted during the winter seasons of 2003-04 and 2004-05 at the Agricultural Research Station, Mandor, Rajasthan to determine the effect of crop-weed competition on seed yield and quality of cumin (Cuminum cyminum L.). The results revealed that weed-free upto 60 DAS gave the lower mean weed density and total weed dry matter at harvest and increased yield attributes viz., mean final plant stand, umbels/plant, seeds/umbel and test weight by 157.9, 147.4, 166.2 and 37.2%, respectively, and mean seed yield by 788.7% over weedy check. This treatment stood at par with complete weed-free and weedy upto 15 DAS with regards to yield attributes and seed yield. The critical period of crop-weed competition was observed between 15 to 60 DAS in cumin. Weed-free environment throughout crop season produced the maximum oil and protein content, and was significantly higher compared to weedy check.

A field experiment was conducted during the summer seasons (December-January to April-May) of 1998-99 and 1999-2000, to study the relative efficacy of four pre-emergence herbicides and soil solarization treatment in reducing weed infestation and in enhancing the yield of brinjal. Season-long crop-weed competition reduced the yield of brinjal by 51 and 49% during 1998-99 and 1999-2000, respectively. Soil solarization for one month registered the highest fruit yield during both the years (18.92 and 18.12 t/ha, respectively). The pre-emergence herbicides alachlor (2.0 and 2.5 kg a. i./ha), oxadiazon (0.5 and 0.75 kg a. i./ha) and pendimethalin (2.0 kg a. i./ha) and hand weeding twice treatments recorded fruit yields comparable to that of soil solarization. As far as weed dry weight is concerned, alachlor (2.0 and 2.5 kg a. i./ha) recorded excellent weed control comparable to weed free check at 30 and 60 DAT.

An experiment was conducted during 2005 and 2006 at the Research Farm of the Department of Agronomy, Agrometeorology and Forestry, PAU, Ludhiana in order to control some hardy weeds like Acrachne racemosa, Commelina benghalensis, etc. in groundnut. Crop treated with pre-plant application of fluchloralin 0.675 kg and pre-emergence application of pendimethalin 0.75 kg, oxyflourfen 0.25 kg and alachlor 1.25 kg/ha each f. b. one hand weeding as well as oxyflourfen 0.50 kg/ha alone produced significantly higher pod yield and significantly less weed dry matter accumulation as compared to the recommended treatment i. e. fluchloralin 0.675 kg/ha during both the years. However, during second year pre-plant application of trifluralin 0.75 kg/haf. b. one HW, trifluralin 1.0 kg , oxyflourfen 0.25 kg+pendimethalin 0.5 kg, oxyflourfen 0.25 kg+trifluralin 0.75 kg/ha and two hand weedings treatments also resulted in significantly higher pod yield and significantly less weed dry matter accumulation than recommended treatment. On the basis of average of two years, all the herbicidal treatments except alone application of fluchloralin 0.675 kg and pendimethalin 1.0 kg/ha produced significantly higher pod yield than unweeded control treatment. Integration of hand weeding with pre-plant application of fluchloralin 0.675 kg and trifluralin 0.75 kg as well as pre-emergence application of pendimethalin 0.75 kg , oxyflourfen 0.25 kg and alachlor 1.25 kg/ha increased pod yield by 39.1, 43.0, 54.6, 54.5 and 55.9% than unweeded control and 14.7, 17.9, 27.5, 27.4 and 28.4% than alone application of fluchloralin 0.675 kg/ha (recommended).