Evaluating Weed Management Strategies and the Differential Effects of Herbicides on Weed Dynamics and Crop performance of Foxtail Millet Grown under the Irrigated Conditions of Rayalaseema

At the wetland farm of S.V. Agricultural College, Acharya N.G. Ranga Agricultural University, Tirupati, Andhra Pradesh, India, a field experiment was carried out during the (rainy season) kharif 2020 to evaluating weed management strategies and the differential effects of herbicides on weed dynamics and crop performance of foxtail millet [Setaria italica (L.) Beauv] grown under the irrigated conditions of Rayalaseema. The current study has shown that the application of pre-emergence pretilachlor 500 g ha-1 with intercultivation at 20 DAS was followed by hand weeding twice at 20 and 40 DAS and it led to the highest weed control efficiency, including foxtail millet's nutrient uptake, and the lowest weed density and dry weight. In unweeded check, a heavy weed infestation reduced the amount of nitrogen, phosphorus, and potassium absorbed by crop by 45.67, 18.03, and 35 kg ha-1, respectively. Crop growth parameters, straw and grain production was increased by hand weeding twice, however the benefit-cost ratio lagged behind the most effective weed management strategy, which is applying pre-emergence of pretilachlor 500 g ha-1with intercultivation at 20 DAS. The present experiment indicated that wherever the labour availability for hand weeding is abundant and cheaper, one can go for hand weeding or opt for the said herbicide recommendation taking into the economical considerations.

Impact of Pre and Post-emergence Herbicide Mixtures in Direct Seeded Rice (Oryza sativa L.)

Rice (Oryza sativa L.) is a major source of food for more than half of the world population especially in South and Southeast Asia and Latin America. A field experiment was conducted at Krishi Vigyan Kendra, Yamunanagar district, Haryana during Kharif season of 2022 to study the effect of pre and post-emergence herbicides combinations herbicides in direct-seeded rice under irrigated condition. The experiment was laid out in a Randomized block design with three replications. The weed management treatments were T1: Pendimethalin + pyrazosulfuron T2:Pendimethalin + pyroxasulfone, T3:Pretilachlor + pyrazosulfuron, T4: Fenoxaprop-p-ethyl with safener + ethoxysulfuron,T5: Cyhalofop-butyl + penoxsulam and metsulfuron-methyl + chlorimuron-ethyl, T6.:Triafamone + ethoxysulfuron, T7: Pendimethalin + pyrazosulfuron fb bispyribac-sodium, T8: Pendimethalin + pyroxasulfone fb bispyribac-sodium, T9:Pretilachlor + pyrazosulfuron fb bispyribac-sodium, T10:Pendimethalin fb fenoxaprop-p-ethyl + ethoxysulfuron T11: Weed free, T12:Weedy check. Among herbicides, application T10 (pendimethalin fb fenoxaprop-p-ethyl + ethoxysulfuron) and T5 (cyhalofop-butyl+ penoxsulam and metsulfuron methyl + chlorimuron ethy (pre-mix) was superior over other treatment. Application of pendimethalin fenoxaprop-p-ethyl + ethoxysulfuron reduced 58.89% grassy weed and 50 % BLWs compared to weedy check plot at 60 DAS. Assessment at 60 DAS and at harvest showed that bispyribac-sodium was effective in controlling E. colona and E. crus-galli. However, bispyribac-sodium did not control D. aegyptium and L. chinensis. Fenoxaprop significantly reduced the densities of Dactyloctenium aegyptium, L. chinensis, and Digitaria sanguinalis. Fenoxaprop tank-mix with ethoxysulfuron appeared to be synergistic for the control of E. crusgalli and E. colona, and Cyperus sp. as this tank mixture. Integration of pendimethalin fb fenoxaprop-p-ethyl+ ethoxysulfuron provided control of all type of weeds with highest grain yield (6.1 t ha-1) among different treatments which was statistically at par with weed free (6.3 t ha-1). In economics points of views, the highest B-C ratio (3.03) was obtained in cyhalofop-butyl + penoxsulam + metsulfuron methyl + chlorimuron ethy followed by pendimethalin fb fenoxaprop-p-ethyl + ethoxysulfuron (2.98).

Effect of Weed Management Practices on Growth, Yield and Quality of Okra [Abelmoschus esculentus (L.) Moench]

The present investigation entitled “Effect of weed management practices on growth, yield and quality of okra Abelmoschus esculentus (L.) Moench)” was conducted at Vegetable Research Farm, Chandra Shekhar Azad University of Agriculture and Technology, Kanpur during kharif season 2022. The experiment was laid out in Randomized Block Design with seven different treatments viz. T1 = Pre-emergence application of Pendimethalin @ 6 ml /L, T2= Post emergence application of Quizalofop-ethyl @ 0.040 kg/ha ,T3 = Pre-emergence application of pendimethalin @ 6 ml/L + one hand weeding at 40 DAS , T4 = Post emergence application of Quizalofop-ethyl @ 0.040 kg ha-1 at 25 DAS + one hand weeding , T5 = Pendimethalin @ 6 ml /L as pre-emergence + Quizalofop-ethyl @ 0.040 kg ha-1 at 25 DAS , T6 = Weed free check (Three hand weeding) 20, 40 and 60 DAS , T7 = weed check control replicated thrice. The result of the study revealed that at 30 DAS maximum plant height (30.96cm) was reported in treatment T3 : Pre-emergence application of Pendimethalin @ 6 ml/L + one hand weeding at 40 days of sowing whereas at 60 and 90 DAS maximum plant height (75.50 and 113.53 cm) was reported in T6 : Weed free check (Three hand weeding) 20, 40 and 60 DAS. Maximum number of branches per plant (4.60)at 60 DAS was found in T3 : Pre-emergence application of Pendimethalin @ 6 ml/L + one hand weeding at 40 DAS and 90 DAS maximum number of branches per plant (5.86) was reported in T6 : Weed free check (Three hand weeding) 20, 40 and 60 DAS. Maximum number of nodes (17.83 ) at 60 days after sowing was noticed in treatment T3 = Pre-emergence application of Pendimethalin @ 6 ml/L + one hand weeding at 40 DAS and 90 Days after of sowing maximum number of nodes () was in treatment T6 = Weed free check (Three hand weeding) 20, 40 and 60 DAS. Maximum Pod diameter( 1.74cm) , fruit weight (12.88gm ), pod length( 14.1cm) , number of pods per plant( 25.66 ) , pod yield per plant ( 304.73gm) , pod yield per hectare (16.91 t), TSS( 3.2 Brix), crude fibre (8.46%) and cholorophyll content (1.18 mg) and relative cholorophyll content (54.39) .

Effect of Weed Management Practices on Growth, Yield of Vegetable Cowpea (Vigna unguiculata (L.) Walp.) cv. Kashi Kanchan

The present investigation contains seven different treatments viz., weedy check (control), weed free check (3 hand weeding) (first hand weeding at 25 DAS), pre-emergence application of Pendimethalin @ 6ml/L, pre-emergence application of Pendimethalin @ 6ml/L + one hand weeding, pre- emergence application of Pendimethalin @ 6ml/L + post emergence @ 40-50 g/ha at 25 DAS, post-emergence application of Metribuzin @ 525g/ha at 25DAS and post-emergence spray of Imazethapyr @ 100 g ai/ha at 25 DAS replicated thrice. The cowpea variety ‘Kashi Kanchan’ was used in experiment. Results of the experiment revealed that though, the weed free check (T2) recorded zero weed population and slightly higher values of growth and yield parameters but among tested treatments, pre-emergence application of Pendimethalin @ 6ml/L + one hand weeding (T4) and pre-emergence application of Pendimethalin @ 6ml/L + Quizalofop ethyl @ 40-50 g/ha at 25 DAS(T5) significantly reduced weed number (48.12 and 52.18/m2) and produced significantly highest plant height (47.30 and 45.98 cm), pod length (21.64 and 20.86 cm), number of pods/plant (35.94 and 34.18), average pod weight(11.18 and 11.06 g), green pod weight/plant (367.84 and 348.63g), green pod weight/plot (11.24 and 10.54 kg) and green pod yield per hectare(118.96 and 111.55q). However, these three treatments (T2, T4 and T5) were statistically at par with each other in terms of growth and yield parameters.Hence, these two weed management practices (T4 and T5) may serve as alternative of manual weeding and may be recommended for farmers of the central plain zone of Uttar Pradesh for higher returns from vegetable cowpea crop.

Weed Management in Clusterbean under the Application of Different Agrochemicals and Phosphorus Levels

Among the Kharif legumes clusterbean (Cyamopsis tetragonoloba L. Taub) is important crop and popularly known as “Guar” in India. A field experiment was conducted during Kharif 2013 at Agronomy Farm, S.K.N. College of Agriculture, Jobner, Jaipur (Rajasthan) to evaluate the weed management in clusterbean under the application of different agrochemicals and phosphorus levels. The treatments comprising 6 weed control treatments (Weedy check, one hand weeding at 20 DAS, two hand weeding at 20 and 40 DAS, pendimethalin at 0.75 kg/ha, imazethapyr at 100 g/ha and fenoxoprop-p-ethyl at 70 g/ha and four levels of phosphorus (0, 20, 40 and 60 kg/ha) assigned to main and sub plots of spilt plot design, respectively and replicated thrice. Results showed that HW twice at 20 and 40 DAS and pre emergence application of imazethapyr at 100 g/ha resulted significant reduction in weed density and weed dry matter in comparison to most of the treatments. Results further indicated that application of 60 kg P2O5/ha in clusterbean recorded the highest density and dry weight of weeds at all the stages. Maximum weed control efficiency was recorded under two hand weeding at 20 & 40 DAS.

Evaluation of Mulching Effects on Weed Control in Blackgram Production under Irrigated Condition

A field experiment with the objectives to understand the evaluation of mulching effects on weed control in blackgram production under irrigated condition involving two factors viz., mulching (paddy straw mulching, sugarcane trash mulching, no mulching) and herbicidal treatments (pendimethalin pre-emergence (PE) @ 1.0 Kg/ha, pendimathalin + Imazethapyr (pre-mix) pre-emergence Valor 32% EC 1.0 Kg/ha, Hand weeding on 15 and 30 days after sowing, weedy check) was undertaken in Factorial Randomized Block Design (FRBD) design with three replications at the instructional farm of Karunya Institute of Technology and Sciences, Coimbatore region of western Tamil Nadu during the cropping seasons of Rabi 2022-23. Results revealed that paddy straw mulching sequential application of Pendimathalin + Imazethapyr (pre-mix) pre-emergence Valor 32% EC and sugarcane trash mulching sequential application of pendimathalin + imazethapyr (pre-mix) pre-emergence Valor 32% EC recorded lower weed density, weed dry weight and maximum crop yield as well as net returns over rest of the mulching and herbicidal treatments.

Avaliação dos potenciais fitotóxico e citotóxico de Pyrostegia venusta (Ker gawl. ) Miers (Bignoniaceae) / Evaluation of phytotoxic and cytotoxic potential of Pyrostegia venusta (Ker-gawl. ) Miers (bignoniaceae)

Pyrostegia venusta (Ker-Gawl.) Miers (Bignoniaceae) é uma espécie com expressiva dispersão em quase todo o sul e sudeste do Brasil, muito utilizada na medicina popular e considerada uma planta invasora. O potencial fitotóxico do extrato hidroalcoólico das flores de P. venusta foi testado por meio de bioensaios de germinação (pré e pósemergência) e de ação tóxica sobre o índice mitótico de sementes de Lactuca sativa (Asteraceae) (alface). A triagem fitoquímica foi realizada para averiguação de substâncias presentes no extrato floral. As diferentes concentrações do extrato mostraram alteração nos diferentes índices de germinação, no comprimento radicular e interferência sobre o índice mitótico. A triagem fitoquímica mostrou a presença de substâncias como terpenos, esteroides, flavonoides, taninos condensados e saponinas, compostos que podem estar associados diretamente com os resultados de fitotoxicidade e citotoxicidade observados. P. venusta possui componentes aleloquímicos capazes de prejudicar a germinação e crescimento radicular de alface.

Pyrostegia venusta (Ker-Gawl.) Miers (Bignoniaceae) is a species with a wide distribution in nearly all of Southern and Southeastern Brazil, has long been used in folk medicine and is considered an invasive plant. The phytotoxic potential of a hydroalcoholic extract of the flowers of P. venusta was evaluated by the germination (pre and post-emergence) and the phytotoxicity bioassays (mitotic index) on the test plant Lactuca sativa (Asteraceae) (lettuce). A phytochemical screening was performed to identify the components of the floral extract. Different concentrations of the extract caused changes in the germination parameters, the root length and the mitotic index. The phytochemical screening indicated the presence of substances such as terpenes, sterols, flavonoids, tannins and saponins, which are compounds that may be associated directly with the results of cytotoxicity and phytotoxicity observed. P. venusta has allelochemical components capable of impairing the germination and root growth of lettuce.

Potencial alelopático e levantamento do banco natural de sementes sob a copa de Copaifera langsdorffii Desf p / Allelopathic potential and survey of natural seed bank under the canopy of Copaifera langsdorffii Desf

O objetivo deste trabalho foi avaliar o efeito alelopático de amostras de solo coletadas sob a copa de três espécimes de Copaifera langsdorffii na germinação de Lactuca sativa e realizar o levantamento do banco natural de sementes de acordo com a sazonalidade. Para testar o efeito alelopático realizou-se experimentos de pré e pós-emergência com sementes de L. sativa e para quantificar o estoque de sementes, amostras de solo foram coletadas de três espécimes em três distâncias do caule (1, 2 e 3m) e em três profundidades (0-5, 5-10 e 10-15cm), na região de cerrado nas estações seca e úmida. As amostras testadas nos ensaios de pré-emergência não interferiram significativamente nos índices de germinabilidade, tempo médio e velocidade de germinação; porém, demonstrou diferença no sincronismo de germinação, independentemente da estação de coleta. No ensaio de pós-emergência foi observada diferença estatística nos parâmetros avaliados (comprimento da raiz primária e hipocótilo) em ambas estações. Para quantificação do banco natural de sementes foram feitas analises macroscópicas de cada amostra de solo com auxílio de microscópio esteroscópico. A análise do banco natural de sementes demonstrou maior número das mesmas na profundidade de 0-5cm e na distância de 2m para ambas estações. Os resultados obtidos sugerem a presença de substâncias aleloquímicas nas amostras de solo coletadas sob a copa de Copaifera langsdorffii.

The aim of this study was to evaluate the allelopathic effect of soil samples collected under the canopies of three specimens of Copaifera langsdorffii the germination of Lactuca sativa and survey the natural seed bank according to seasonality. To test the allelopathic effect was carried experiments of pre and post-emergence with seeds of L. sativa and to quantify the stock of seeds, soil samples were collected from three specimens at three distances from the stem (1, 2 and 3 m) and at three depths (0-5, 5-10 and 10-15cm) in the region of savanna in the dry and wet seasons. The samples tested in bioassay of pre-emergence no significant influence on germinability, mean germination time and mean germination speed, but showed a difference in the synchronism of germination, these data were independent of sampling station. In test for post-emergence was observed statistical difference in the parameters evaluate (length of primary roots and hypocotyls) in both seasons. To quantify the natural seed bank were macroscopic analysis of each soil sample with the help of stereoscopic microscope. The analysis of the natural seed bank showed a larger number of seeds in the 0-5cm and in distance of 2m for both seasons. The results suggest the presence of allelochemical substances in soil samples collected under the canopy of Copaifera langsdorffii.