Isoproturon at 1.0 kg. metoxuron at 1.6 kg and methabenzthiazuron 1.4 kg ha-' applied at 3-leaf stage provided more than 80% control of both susceptible (5) biotypcs (RI and H2) of P. milloI': however. these herbicides were ineffective against resistant (R) biotypes (H3, KRI and UPI) even at higher doses. Mon-48549 at 25 and 50 g, and Foe5043 at 300 and 600 g ha-' also did not control this weed satisfactorily. Performance of diclofop and metribuzin was also erratic against Rand S biotypes. Clodinafop at 60 g, fenoxaprop at 120 g, sulfosulfuron at 25 g and tralkoxydim at 350 g ha-' applied at 3-leaf stage resulted in 82-95% reduction in the dry weight of R as well as 5 biotypes of P. lIlilUJI: Metribuzin at 200 and 400 g ha", and Mon-48549 at 25 and 50 g ha-' caused 15 to 30% phytotoxicity to wheat. Metribuzin either alone or in mixture caused phytotoxicity to wheat crop without adding to weed control efficiency (WCE).

Pot experiments were conducted to find out GR,,, values of isoproturon. clodinafop. sulrosulfuron and fenoxaprop-p-ethyl for controlling Phalaris minor. Clodinafop. sulfosulfuron and fenoxaprop-p-ethyl were recommended at 60. 25 and 100 g ha". On an average of two years, GR,o values for isoproturon. clodinafop, sulfosulfuron and fenoxapropp- ethyl were found to be 1210, 2.47. 2.08 and 7.58 g ha-I, respectively. Among the alternate herbicides, lowest GR,,, value was observed in clodinafop which was followed by sulfosulfuron and fenoxaprop-p-ethyl and these values were many times lower than their recommended doses; however. GR,o values for isoproturon were found to be much higher

than even its recommended dose.

Weed control efficacy of clodinafop applied at varying doses with surfactant and without surfactant was evaluated in wheat. With the increase in the doses of clodinafop from 40 to 50 or 60 g ha·'. there was a gradual decline in the population and dry matter accumulation of grassy weeds. Addition of surfactant (0.25 or 0.5 or 1.0%) enhanced the grass weed control efficacy of c1odinafop. However, no significant difference was observed in c1odinafop efficacy with different surfactant concentrations. Clodinafop did not provide any control of broad leaf weeds. Maximum wheat yields of 4891 and 5163 kg ha" were observed in season long free situations followed closely by diclofop-methyl 700 g. c1odinafop 60 and 50 g with surfactant applied after first irrigation.

The dry matter of Kandyali palak (Rumex .lpiIlOSUS) tended to increase with the increase in its population, whereas wheat grain yield showed negative correlation with population. On an average of two years, presence of one plant m·l of R..lpiIlOSUS reduced grain yield by 2.5% and two and three plants m·l by 6.1 and 20.1%. respectively. Further 30.1. 49.0 and 116.1% reduction in grain yields was recorded with 5, 10 and 30 plants m" of R. SpiIlOSIlS.

Oiclofop, metsulfuron, 2, 4-0 Na, diflufenican, clodinafop, fenoxaprop, tralkoxydim and isoproturon applied in wheat did not exhibit any adverse effect on various kharif crops of mungbean, maize, cowpea, pigeon pea, pearl millet and cotton. Chlorsulfuron at 30 g ha" sprayed in wheat had no residual effect on mu,!gbean but at 60 and 120 g ha" had residual toxicity to mungbean. Compared to mungbean and cotton, maize was more sensitive to chlorsulfuron. Sulfosulfuron at 25 g ha" and pendimethalin at 1500 g ha" applied in wheat also caused residual toxicity to maize but not to mungbean and cotton. Metribuzin at 300 and 400 g ha" caused significant residual toxicity to mungbean and maize, and at 400 g ha" to cotton. Chlorsulfuron, sulfosulfuron, metribuzin and pendimethalin significantly reduced the density and dry weight of Trianthema portulacastrum at 210 days after treatment.

Carfentrazone-ethyl against Chenopodium album. MeJilotus alba, MeJi/otus indica. Lathyrus aphaca, Vicia sativa, Medicago dellliculata and Rumex acetosella. Its weed control efficiency at 20 g ha- ' ranged from 90.6 to 100%. Carfentrazone at 20 and 25 g ha- ' had better efficacy than 2, 4-D and was comparable with metsulfuron methyl. Total weed dry matter production in 2, 4-D treated plots was higher than that of carfentrazoneethyl at 15 and 25 g ha-'. The grain yields recorded with carfentrazone-ethyl at 15 and 25 g ha-J and metsulfuron methyl at 4 g ha-' were similar to weed-free treatment.

Chlorsulfuron, clodinafop, fenoxaprop, sulfosulfuron, tralkoxydim and dithiopyr alone and in combination were evaluated against complex flora of weeds in wheat. All the herbicidal treatments significantly reduced the dry weight of complex weeds. Chlorsulfuron was effective against broadleaf weeds and ineffective against grassy weeds. Fenoxaprop, clodinafop and tralkoxydim controlled grassy weeds but not the broadleaf weeds. Sulfosulfuron was very effective against grassy weeds and also to some extent against non-grassy weeds. Dithiopyr alone or in tank mixture was ineffective. Tank mixture of fenoxaprop+ chlorsulfuron at 100+20 g, clodinafop+chlorsulfuron at 50+20 g, tralkoxydim+ chlorsulfuron at 250+20 g and sulfosulfuron+chlorsulfuron at 15+10 g ha'\ provided 73-84% control of complex weed flora and being at par with each other produced grain yield of wheat similar to weed-free. Isoproturon+2, 4-D sodium salt at 750+500 g ha'\ resulted in 72-75% control of both types of weeds and produced grain yield equivalent to weed-free in one season.

Performance of irrigation time and weed management practices against weeds in wheat was evaluated. Chenopodium album L. and Chenopodium murale L. were predominating weed species and comprised about 76% of total weed population in weedy check. Pre-sowing irrigation reduced the dry weight of C. album and C. murale by 21 and 25%, respectively, and subsequently grain yield was 12% higher over post-sowing irrigation. Pre-emergence application of pendim~thalin at 0.75 kg ha" supplemented by one hand weeding or 2, 4-D, 0.50 kg ha" at 30 DAS gave significantly higher grain yield due to better weed control. However, the higher additional net return (Rs. 8063) was also obtained with pendimethalin at 0.75 kg ha"+one hand weeding.

Weed control efficacy of Affinity at 1.75 and 2.00 kg ha" was higher than at 1.5 kg ha" on Chenopodium. Affinity at all the doses was equally effective. Affinity at 2.0 kg ha" was comparable with isoproturon at 1.33 kg, c1odinafop at 60 g and sulfosulfuron at 20 g ha" with respect to control of P. minor. Affinity at higher doses being at par with isoproturon at 1.33 kg ha", sulfosulfuron at 25 g ha" and weed-free treatments yielded significantly more than all other treatments.

Fenoxaprop. tralkoxydim and clodinafop. being very effective (87-91%) against Avella ludovicialla and Phalaris millor, were not effective against broadleaf weeds in wheat. Tank mixture of fenoxaprop+isoproturon at 1000 and 1250 g ha- I • and tralkoxydim+isoproturon at 250+375 and 250+500 g ha-J being statistically at par with each other and better than their alone applications, reduced the dry weight of complex weeds to the extent of 72-78%. Tank mixture of metribuzin with reduced dose of c1odinafop, fenoxaprop, sulfosulfuron, chlorsulfuron or tralkoxydim increased their efficacy against grassy weeds without any additional grain into grain yield of wheat. Isoproturon and metoxuron being at par with each other proved superior to alone applications of metribuzin and its tank mixed applications with isoproturon or metoxuron.

In wheat broadleaf weeds were dominant (82.87%) especially infested by ChenopodiulI/ spp. Application of metsulfuron-methyl was very effective against the broad-leaf weeds and did not have residual effect on succeeding soybean crop. Metsulfuron methyl at 4 g ha'! was most effective in controlling broadleaf weeds and better than 2, 4-D and farmers' practice in increasing wheat yield.

Isoproturon resistant biotypes of P. minor gained more plant height, leaf area and dry matter as compared to their susceptible counterpart from Kamal area. Susceptible biotypes from Bawal and Rohtak also gained more height as compared to that from Kamal but were slower to grow as compared to the resistant ones. All the resistant ones were dissimilar from their susceptible counterpart in the absence of three protein bands at molecular weights 15.8, 14.1 and 7.9 kdaltons.

Weed control efficacy of clodinafop at 50 g, fenoxaprop at 100 g, sulfosulfuron at 20 g and tralkoxydim at 300 g ha- ' ranged between 78-96% on grassy weeds. These herbicides were totally ineffective against broadleaf weeds except sulfosulfuron_ Triasulfuron was not effective against grassy weeds, but very effective on all broadleaf weeds. The efficacy of clodinafop at all combinations with triasulfuron was reduced in controlling grassy weeds. However, efficacy of triasulfuron was not affected due to tank mixing.

A field experiment was conducted during two monsoon seasons to find out the efficacy of certain low doses herbicides in transplanted rice. Echinochloa colona, Echinochloa crusgalli, Cyperus rotundus, Cyperus difformis, Fimbristylis milliacea and Ludwigia parviflora were the major weeds. Almix+2, 4-DEE at 15+500 g ha·1 applied eight days after transplanting was found most effective in controlling weeds and maximizing rice grain yield (5837 kg ha·1). This was on par with hand weeding done thrice at 20, 40 and 60 days stage. The weed competition in weedy check caused 46% reduction in grain yield.

Pyrazosulfuron-ethyl at 25 g ha- I applied 10 days after transplanting (OAT), tank mixed (3 OAT) or sequential application of butachlor 938 g ha- J (3 OAT) and Almix at 4 g ha- I (25 OAT) were identified as promising alternatives to the commonly used herbicide butachlor at 1:5 kg ha- 1•

Tirazolopyramidine was effective in reducing density of Echinochloa colona, lschaemum rugosum, Cyperus iria, Fimbristylis miliacea and other weed spp. Its weed control efficacy was much less at 10 and 12.5 g ha- I . Grain yield increased significantly with increase in doses of triazolopyramidine sulfonamide from 10 to 25 g ha-'. None of the doses of triazolopyramidine had phystotoxic effect on transplated rice crop. Triazolopyramidine at 20 and 25 g ha·1 applied 15 DAS produced grain yields similar to weed-free treatments.

Effect of weed management and boro rice cultivars on growth and yield of boro rice and weeds was evaluated for three seasons. Cultivar 'Gautam' recorded the highest grain yield of 4.12 t ha" and cultivar 'Prabhat'proved better in minimizing the weed infestation. Application of butachlor at 1.5 kg pre-emergence+2,4-D at 0.5 kg ha· 1 post-emergence produced grain yield similar to hand weeding twice (30 and 50 DAT).

Bio-efficacy of acetochlor doses and stages of application were studied in transplanted rice. Sacciolepsis interrupta. Leersia hexandra. Scirpus juncoides. Fissendocarpa linifolia and Monochoria vaginalis were the dominant weeds. Application of acetochlor at 100 g ha" at three or eight days after transplanting resulted in significant reduction in weed

density, weed dry matter accumulation and was at par with higher doses (125, 150 and 300 gha·'). The highest grain yield of rice was recorded with the application of acetochlor at 100 g ha-' applied three days after transplanting.

Almix alone at 4 g ha- ' was effective in reducing the density of non-grasses and sedges in transplanted rice. Butachlor alone at 1250 g ha- ' was effective against annual grasses. Almix at 4 g ha- ' was compatible witli butachlor as tank mixed application. Almix at 4 g ha- J as tank. mixed or follow up application over pre-emergence application of butachlor increased weed control spectrum and efficacy and produced grain yields at par with weedfree and higher than alone application of butachlor or Almix.

Field experiment was conducted for two consecutive summer seasons (1999 and 2000)

at Kukumseri on sandy loam soil to evaluate promising herbicide combinations for weed

control in pea. Alachlor at 1.0 kg+pendimethalin at 0.9 kg ha· l and alachlor at 1.0 kg+

isoproturon al.1.0kg ha- l were statistically similar tQ alachlorat 1.5 kg ha· l, pendimethalin at

1.2 kg ha· l and hand weeding twice in reducing density and dry weight of weeds. These were

significantly su~rior in reducing weed density and weight as compared to other treatments.

Alachlor at 1.0 kg+pendimethalin at 0.9 kg ha- l recorded the highest weed control efficiency

of 87.5%. Pendimethalia 1.2 kg ha· l gave highest grain yield which was significantly higher

than pendimethalin at 0.9 kg+isoproturon 0.75 kg ha· l, ~ndimethalinat 0.6 kg+isoproturon

at 1.0 kg ha- l, pendimethalinat 0.6 kg+isoproturon at 0.75 kg ha-land alachlor at

0.75+isoproturon at 0.75 kg ha- l. Alachlor at 1.50 kg ha- l recorded highest marginal benefit

cost ratio (MBCR). The combinations of alachlor at 0.75-1.00 with isoproturon at 0.751.00

kg ha· l were superior to other herbicide treatments in increasing MBCR.

Application of herbicides viz., pendimethalin (1.00 kg ha") as pre-emergence followed by fluazifop-p-butyl (0.375 kg ha") as post-emergence demonstrated cent per cent mortality of Trianthema monogyna, a major dominating broad-leaved weed and Sorghum halepensea perennial grass, respectively, and recorded seed yield (1012 kg ha") similar to that obtained under weed-free check (1016 kg ha").

A field experiment was conducted for two summer reasons to identify critical period in irrigated summer sown blackgram (Vigna mungo L.) at Kanpur. Unchecked weed competition throughout the crop growth period caused a reduction of 40.10% in seed yield. Initial weed condition for the first 10 days after sowing did not cause significant loss in yield. Weed-free conditions maintained 40 days after sowing could not bring significant increase in seed yield. The critical period of crop-weed competition thus lies between 1040 days after sowing in irrigated summer sown blackgram.

Chlorimuron-ethyl at various doses (6. 9 and 18 g ha") was effective on non-grassy weeds in soybean without any phytotoxicity. Chlorimuron-ethyl at 9 g ha'\ was better than at 6 g ha·'. Application at 3 or 7 DAS was more effective than at 15 DAS. Grain yields due to chlorimuron-ethyl at 9 g ha" applied 3 or 7 DAS were at par with weed-free treatment.

Oxadiargyl at 50 g ha" applied 20 days after sowing proved most effective in

minimizing weed growth and enhancing the seed yield of cumin which was similar to that of

pendimethalin at 1.0 kg ha·'. Oxadiargyl at 75 g ha" and above showed some phytotoxicity

symptoms on cumin leaves which was recovered at later stages. Residual effect of oxadiargyl

was not observed on succeeding crops of mothbean and pearl millet.

The weed density at 20 days after sowing was increased significantly upto 40 kg N ha", whereas at 60 DAS they were significantly counted maximum only at 20 kg N ha". Weed dry weight at harvest was not influenced due to increasing levels of N. Significantly the higher seed yield and yield attributes were recorded under the application of 60 kg N ha·'. Pre-etn~rgence application of oxadiazon at 0.5 kg ha" was most effective in controlling weeds which enhanced growth and yield components and resulted in production of higher coriander seed yield (2599 kg ha") and net monetary return of Rs. 42354. This treatment was at par with pendimethalin. The interaction effect of N and weed management treatments were not significant.

Field experiments were conducted to study the efficacy of different weed management practices in sugarcane during 1997-99. Cyperus rotundus, Cynodon dactylon and Sorghum halepense were the dominating weeds associated with the crop and constituted 42, 21 and 17.5% of total weed population, respectively. One hoeing at 30 days after planting followed by application of atrazine at 2.0 kg ha'! (just after hoeing) provided 70.5% weed control efficiency. This also resulted in highest cane yield being 49.5% higher than weedy and 2.4% than three hoeings done at 30, 60 and 90 days after planting. The weed infestation did not affect juice sucrose content. Commercial cane sugar yield was highest (10.0 t ha'!) with three hoeings during 1997-98 and with one hoeing fb atrazine (11.0 t ha'!) during 1998-99, though the differences were non-significant.

Weed density and weed dry matter reduced significantly due to different weed control measures. Cane yield increased significantly with all the measures over weedy check and was highest under weed-free conditions though it was at par with manual hoeing 20, 40, 60 DAP and at harvest of intercrops. Cowpea was most effective in smothering weeds followed by greengram and blackgram. Cowpea, blackgram and greengram reduced cane yield by 5.2, 10.4 and 8.4%, respectively. Sugarcane+cowpea gave highest mean cane equivalent yield of 108.4 t ha·1 with net return of Rs. 68684 and B : C ratio of 2.24 as against 77 t ha·l, Rs. 43264 and 1.44 with sole sugarcane. CEY and net return also followed the same trend. Atrazine greatly hampered the emergence of the intercrops.

Glyphosate at 0.5 kg ha"+surfactant (0.1 %) and glyphosate at 1.0 kg ha" provided most effective control of Erigeron canadensis but was toxic to the grasses in natural grasslands. Significantly higher herbage yield was recorded by 2, 4-D Na at 0.75 kg ha"+surfactant (0.1%) and 2, 4-D (EE) 1.25 kg ha· '.

Glyphosate at 0.5 kg ha"+surfactant (0.1 %) and glyphosate at 1.0 kg ha" provided most effective control of Erigeron canadensis but was toxic to the grasses in natural grasslands. Significantly higher herbage yield was recorded by 2, 4-D Na at 0.75 kg ha"+surfactant (0.1%) and 2, 4-D (EE) 1.25 kg ha· '.

Allelopathic effect of basil (Tulsi) (Ocymum sanctum) on the germination of some weed species was evaluated. The germination of radish, redroot pigweed, hairy beggarticks and guineagrass was completely inhibited with addition of 7.5 g basil leaf powder to 100 g of sand as compared to plants grown in sand alone or in a mixture of sand and sphagnum. The germination of seeds was significantly inihibited in redroot pigweed (13%) and hairy beggarticks (12%) when grown in 10% (w/v) basil leaf extract as compared to distilled water. Significantly lower germination of 58, 47 and 45% with basil stem+root extract (at 2.5% w/v) was recorded, respectively, in radish, redroot pigweed and hairy beggarticks. The length of radicle+root in case of redroot pigweed and hairy beggarticks was significantly lower in basil stem+root extract (2.5% w/v) than in distilled water and was significantly reduced further when the extract concentration was increased to 5% (w/v).

A field experiment was conducted at K. N. K. College of Horticulture, J. N. K. V. v., Mandsaur (M. P.) under AICRP on Medicinal and Aromatic Plants during winter (rabi) seasons of 1995-96 and 1996-97 to find out the suitable weed management practices in opium poppy. Field studies revealed that pre-emergence (PE) application of isoproturon coupled with hand weeding (HW) at 30 days after sowing (DAS) proved more effective in reducing weed population and weed biomass and in increasing yield and attributes of opium poppy than isoproturon applied as pre-emergence alone. Isoproturon at 375 g ha" PE+HW at 30 DAS and isoproturon at 500 g ha· 1 PE+HW at 30 DAS were as effective as weed-free check in reducing density and biomass of weeds and in increasing yield attributing characters viz., capsules planrl, capsule diameter and capsule length and latex, seed and husk yields and net profit. Maximum weed mortality (WM, 92.1%) with latex yield (74.6 kg ha"), seed yield (711.3 kg hal), husk yield (744.3 kg ha") and net profit (Rs. 42990 ha") were recorded under weed-free check and it was closely followed by isoproturon at 375 g ha" PE+HW at 30 DAS and isoproturon at 500 g ha-' PE+HW at 30 DAS, where 83.6 and 90.1% WM, 70.1 and 62.8 kg ha-' latex yield, 664.3 and 605.3 kg ha-' seed yield, 677.8 and 593.9 kg ha-' husk yield and Rs. 42812 and 36154 ha- ' net profit were recorded, respectively. Morphine content of opium remained unaffected due to use of isoproturon in opium poppy. Uncontrolled weed growth caused 57.4% mean loss in latex (50.8%), seed (61.5%) and husk (59.8%) yields. Higher dose of isoproturon at 500 g ha-' PE caused 22.5% phytotoxicity on opium crop.

Corynespora cassicola, Curvularia sp., Curvularia lunata, Fusarium oxysporum, F. monilifonne, Monilia sp. and Trichoderma harzianum were isolated from Parthenium infested soil of Coimbatore district of Tamil Nadu. Spore suspension as well as culture filtrates of F. oxysporum and F. monilifonne were highly pathogenic to the weed and its seed germination and their pre-emergence and post-emergence applications at 5% level resulted in complete inhibition of seed germination and 100% wilt incidence, respectively. T. harzianum was highly pathogenic to the Parthenium seeds only but not to the established weed.