Country Bean Research Articles

Characterization of bean common mosaic virus isolates infecting three leguminous bean crops from South and Southeast Asia.

Bean common mosaic virus (BCMV) is causing economically important diseases in leguminous crops worldwide. In this study, BCMV isolates from country bean (CB, Lablab purpureus), yard-long bean (YLB, Vigna unguiculata) and rajma bean (RB, Phaseolus vulgaris) collected from Bangladesh, Nepal and Cambodia were characterized. Samples tested positive for BCMV in serological assays were subjected to high-throughput sequencing to generate near full-length genome sequences. In pair-wise comparisons of the polyprotein open reading frame, thirteen BCMV isolates from Bangladesh, Cambodia, and Nepal showed sequence identity of 92.1 to 98.8% at the nucleotide and 94.2 to 99% at the amino acid level among themselves and with corresponding sequences of BCMV reported previously. In phylogenetic analyses using the global BCMV sequences, they segregated into five distinct lineages, with RB isolates from Nepal clustering with US1/NL1-clade of common bean isolates from different countries, YLB isolates aligning with blackeye cowpea strain sequences reported from China, and CB isolates from Nepal and Bangladesh clustering with soybean isolates from China. One YLB isolate from Nepal was identified as a putative recombinant. None of the BCMV sequences aligned with isolates representing the RU1 or PStV clades. In grow-out tests, seed samples from local markets showed 14.3 to 38.1% transmission efficiency rate of BCMV with CB seed lots and from 9.5% to 33.3% with YLB seed lots.

Performance of BSMRAU-developed vegetables under fruit tree-based agroforestry systems

Many field crop lands are being transformed to fruit orchards in different locations of Bangladesh. There is an ample scope to cultivate intercrops in the orchards following scientific manner and proper technology including suitable varieties. In this study, mango and orange orchards were transformed to agroforestry system in Kotchandpur upazila under Jhenaidah district to investigate the performances of selected vegetable varieties (bottle gourd, stem amaranth, papaya, cauliflower, and country bean) developed by the Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU). Randomized complete block design was used to compare agroforestry (mango and orange orchards) and non-agroforestry (open field) treatments for identifying suitable tree-vegetable combinations. The results indicated that yields of the tested vegetables were higher in the non-agroforestry system (crop field without trees) compared to the agroforestry system. Yields of bottle gourd stem amaranth, cauliflower, and country bean in agroforestry systems decreased by 21, 7, 18, and 19%, respectively, compared to non-agroforestry system. On the contrary, yield reductions were 7.9, 15.7, 3.9 and 4.6% in mango-based agroforestry than orange-based agroforestry for bottle gourd, stem amaranth, cauliflower, and country bean, respectively. The findings suggested that although all the tested vegetables can be grown in agroforestry, but creeping type vegetables are less suitable. Despite the observed reduction in yields, the fruit tree-based agroforestry system demonstrated its potential as a viable alternative, offering to reduce crop failure risk to the farmers and optimizing land utilization. The order of the suitability of the tested vegetables are stem amaranth > cauliflower > country bean > bottle gourd in agroforestry systems. Ann. Bangladesh Agric. 27(2):191-199

Assessment of Safe Vegetable Cultivation at Jashore in Bangladesh: Evidence from Country Bean, Cucumber and Pointed Gourd Cultivation

The study was designed to assess the present status and methods of safe vegetable production at farm level in selected areas of Jashore during January-May, 2023. For the study ninety sample farmer were selected by stratified sampling from three sub-district of Jashore. Average farm size was 0.79 ha in study area. Farmer doing different agronomic management such as weeding, irrigation, spraying, de-topping, stalking, earthing up etc. Farmer used different methods simultaneously such as insecticide spray, bio-pesticide, sex pheromone, yellow trap, white trap, hand picking etc. for controlling insect pest. About sixty-four percent farmer sprayed synthetic pesticide and rest of them used bio control method such as bio-pesticide (bio-chamak, eco-mac, bio-envir, bio-cin), sex pheromone trap, yellow trap and hand picking for control insect pest in their fields. About fifty-eight percent farmer used bio-fertilizer along with organic fertilizer (manure, vermin compost) and seventy-eight percent farmer used chemical fertilizer for vegetable cultivation. Total production cost of country bean was Tk.3,36,579 ha-1, cucumber was Tk.3,25,915 ha-1 and pointed gourd was Tk.4,40,106 ha-1. Among the cost item labor cost was highest. Average yield of country bean was 30.60 tha-1, cucumber was 30.08 tha-1 and pointed gourd was 41.60 tha-1. Highest benefit cost ratio was cucumber (2.13) followed by pointed gourd (2.07) and country bean (1.50), that means safe vegetable cultivation also profitable. Farmer awareness, havoc attack of pest and insect were the main problem for safe vegetable cultivation. Market facilities, demand, value chain, proper price for organic vegetable, and farmer motivation can promote and enhance safe vegetable cultivation.

Color, antioxidant and nutritional composition of dehydrated country bean (Lablab purpureus) seeds using solar drying techniques and pretreatments in Bangladesh

The country bean (Lablab purpureus), is a significant contributor of dietary protein and other essential components in human nutrition. Because of its elevated moisture content, it is susceptible to rapid decay, leading to losses after harvesting. The utilization of solar drying has attracted significant attention as a tactic to minimize nutrient depletion in dried goods and enhance their longevity. This study employed four solar drying techniques, namely long chimney, short chimney, box solar drying and open sun drying, along with pretreatments such as potassium metabisulfite, potassium-sodium tartrate, citric acid and ascorbic acid. The objective was to determine an effective solar drying method, combined with pretreatment, that can maintain the color and nutritional qualities of dried country bean seeds. The treatment combinations were organized in a factorial randomized complete block design (RCBD) with three replications. The data were subjected to a two-way analysis of variance (ANOVA) and a Duncan Multiple Range Test (DMRT) was conducted at a significance level of 5 % (p < 0.05). Results revealed that box solar dryer having the highest drying efficiency, retained the highest β-carotene (82.94 %), vitamin C (90.15 %), protein (96.48 %), fat (11.63 %), and ash (90.50 %) with maximum DPPH radical scavenging activity (lowest IC50 209.49 μg/ml) compared to other driers. Besides, country bean seeds have noteworthy proximate compositions, antioxidant activity, and bioactive components treated with 1 % potassium metabisulfite. Furthermore, the country bean seeds dehydrated in box solar dryer after 1 % potassium metabisulfite treatment received the highest acceptance score on the five-point Hedonic scale (4.83–4.89 out of 5.00) and color appearance and the similar trend was further supported by principal component analysis. Thus, it can be inferred that using a box solar dryer with a 1 % potassium metabisulfite pretreatment is a feasible method for preserving the color and nutritional value of country bean seeds and reducing postharvest losses.

Characterization of a New, Country Bean (Lablab purpureus) Lineage of Bean Common Mosaic Necrosis Virus.

Country bean (Lablab purpureus, family Fabaceae) is grown in subsistence agriculture in Bangladesh as a multipurpose crop for food, animal feed, and green manure. This study was undertaken to investigate the genetic diversity of bean common mosaic necrosis virus (BCMNV, genus Potyvirus, family Potyviridae) in country beans. Leaf samples from country beans showing yellowing, vein banding, and mosaic symptoms were collected during field surveys between 2015 and 2019 cropping seasons from farmers' fields in different geographic regions. These samples were tested by serological and molecular diagnostic assays for the presence of BCMNV. Virus-positive samples were subjected to high-throughput Illumina sequencing to generate near-complete genomes of BCMNV isolates. In pairwise comparisons, the polyprotein sequences of BCMNV isolates from Bangladesh showed greater than 98% identities among themselves and shared less than 84% sequence identity at the nucleotide level with virus isolates reported from other countries. In the phylogenetic analysis, BCMNV isolates from Bangladeshi country beans formed a separate clade from virus isolates reported from common beans in other countries in the Americas, Africa, Europe, and from East Timor. Grow-out studies showed seed-to-seedling transmission of BCMNV, implying a possible seedborne nature of the virus in country beans.

Efficacy of Bio-Rational Insecticides in Controlling Thrips in Summer Country Bean

Aims: To study the efficacy of biorational insecticides in controlling thrips in summer country bean.&#x0D; Study design: The study used a single component Randomized Complete Block Design (RCBD) with three replications.&#x0D; Place and Duration of Study: The experiment was conducted in the central farm of Sher-e-Bangla Agricultural University, Dhaka, Bangladesh from March to May 2021.&#x0D; Methodology: The experiment consisted of seven treatments and was laid in a single factor Randomized Complete Block Design (RCBD) with three replications. The experiment consists of the following management practices: T1=Spraying Neem oil @ 6 ml/L of water at 7 days interval, T2=Spraying Neem leaf extract @ 200 mg/L of water at 7 days interval, T3= Mehgoni leaf extract @ 200 mg/L of water at 7 days interval, T4=Tobacco leaf powder @ 30 mg/L of water at 7 days interval, T5= Spraying Spinosad @ 0.4 ml/L of water at 7 days interval, T6=Spraying Biotrin @1.4 ml/L of water at 7 days interval and T7= Untreated control.&#x0D; Results: Among the seven (7) treatments the lowest number of thrips (2.50 plant-1) was observed in T5 (Spraying Spinosad @ 0.4 ml/L of water at 7 days interval), while highest number of thrips (16.67 plant-1) was observed in T7 (Untreated control). The highest percentage of thrips reduction over control (85.50%) was observed in T5 (Spraying Spinosad @ 0.4 ml/L of water at 7 days interval) treatment. The present study revealed that the lowest number of thrips as insect pest and increased plant, leaf, inflorescence and pod infestation, different yield contributing characters and yield of country bean might be obtained by using the treatment T5 (Spraying Spinosad @ 0.4 ml/L of water at 7 days interval) besides T6 (Spraying Biotrin @ 1.4 ml/L of water at 7 days interval) performed as second best treatment whereas, T7 (Control) and T3 (Mehgoni leaf extract @ 200 mg/L of water at 7 days interval) may protect the country bean at lowest rate in summer.&#x0D; Conclusion: It can be concluded that, spraying of Spinosad @ 0.4ml/L of water at 7 days interval as a bio-rational management practice for thrips population control for country bean variety BARI Sheem-4 in summer reduced the infestation of thrips at the most satisfactory level.

Technical efficiency of early variety country bean cultivation in selected areas of Bangladesh: a stochastic frontier approach

The present study was undertaken to measure the profitability and technical efficiency of early variety country bean cultivation in selected areas of Chatmohar upazila of Pabna district. A total of 60 early variety country bean-growing farmers were selected from three villages of Chatmohar upazila using a simple random sampling technique. Stochastic frontier production function was applied to determine the technical efficiency of the country bean growers. Technical inefficiency effects model was also applied to identify the demographic and socio-economic factors by which inefficiency effects are influenced. The study revealed that Benefit Cost Ratio (BCR) was the highest (2.29) for large farmers followed by medium (2.27) and small farmers (2.21). The result of the Maximum Likelihood Estimates (MLE) showed that human labor, fencing and manure had significant positive impact whereas the irrigation and insecticides had a negative impact on the production of country bean. The results of technical inefficiency effect model showed that farmer’s age, farm size had negative impact while education, family size and farm credit had positive impact on technical efficiency. The inefficiency analysis results indicated that farm level technical efficiency ranged between 43.06% and 98.01% with a mean technical efficiency of 91.9% implied that there was potential to increase country bean production among smallholder farmers in the study area by 8.1% through efficient use of present technology. The main constraints to country bean (early variety) production were identified as- infestation of pest and disease, high price of inputs, paucity of quality seed and fertilizer, scarcity of human labor, lack of technical knowledge, limited access to institutional credit etc. Despite the constraints, there is a great prospect of early variety country bean production in the study areas. Country bean (early variety) production could be increased in a sustainable manner if farmers would be provided with government support regarding lower price of input, fair price of output, marketing facilities, training for farmers and farm credit at low interest rate, reducing the activities of syndicate of middlemen. Government should provide necessary support to the farmers for ensuring sustainable production of early varieties of country bean. Res. Agric. Livest. Fish. Vol. 10, No. 2, August 2023: 155-164

Effect of Fruit Peel Biochar on Growth and Yield of Tomato (Solanum lycopersicon Mill.) and Country Bean (Lablab purpureus) in Acidic Soil of Sylhet, Bangladesh

The potential of biochar as a soil conditioner has been approved by scientists worldwide due to its large surface area, high water retention capacity, slow nutrient releasing nature and liming ability; and it might also help to get desirable crop yield in problem soil like acidic soil. Hence, an experimental field trial was operated at the research field of the Department of Agroforestry and Environmental Science, Sylhet Agricultural University, Sylhet to evaluate the performance of banana peel biochar (BB) and orange peel biochar (OB) in the growth and yield of tomato (Solanum lycopersicon Mill.) and country bean (Lablab purpureus) under acidic soil conditions. In case of tomato, plant height (PH), number of leaves plant-1 (NLP), leaf length (LL), and stem diameter (SD) in treatments having different levels of biochar were significantly higher than the control. The maximum PH (72.20 cm), NLP (21), LL (35.66 cm), SD (9.05 cm), and total leaf chlorophyll content (TLCC) (50.56 µmol m-2) of tomato were found in T7 (3% OB w/w + CF) followed by T4 (3% BB w/w + CF) whereas in country bean, the PH (373 cm), NLP (34), branch number (BN) (3), and TLCC (36.65 µmol m-2) were also recorded in T7 followed by T4. The root length (RL) (43.5 cm) and fresh root weight (FRW) (14 g) of country bean were the maximum at T7, followed by T5 (1% OB w/w + CF). According to the results, positive effects of BB and OB application were observed on all the yield parameters of country bean and tomato. The number of pod plant-1 (NPP) (384), individual pod weight (IPW) (5.78 g), total pod weight plant-1 (TPWP) (2220 g), and pod length (PL) (10.57 cm) of country bean were also found to be highest in T7, followed by the T4. Similarly, the highest NFP (37), IFW (55 g), and TFWP (1980 g) of tomato were noted in T7, followed by T4. After the cultivation of country bean and tomato, a significant increase in the soil pH was noticed at T3 (2% BB w/w + CF), T4, T6 (2% OB w/w + CF) and T7 in respect of the control. Therefore, the findings of the study suggest that both BB and OB could have a positive impact on growth and yield components of tomato and country bean by altering soil pH of acidic soil.

Screening of Country Bean (Lablab Purpureus L.) Genotypes for Salinity Tolerance

Thirty-five country bean (Lablab purpureus L.) genotypes collected from coastal belts of Bangladesh were screened for tolerance to a high level of salinity (12 ds m-1 NaCl) in Hogland nutrient solution in a hydroponic system at vegetative growth stage. The experiment was conducted in a complete randomized design with three replications at Genetics and Plant Breeding lab, BSMRAU during January-February, 2016. The genotypes were varied in biochemical properties (proline, carbohydrates, chlorophyll contents etc.), dry root: shoot ratio, relative shoot dry weight and salt susceptibility index (SSI). Wide variation among the genotypes was noticed for root and shoot ratio (p&lt;0.05). Relative shoot length varied from 29.87- 126.04 with an average of 79.29 whereas relative root length showed wide variation with a range of 20.00-300.00. Relative root dry weight (RRDW) varied from 22.06-211.43 with a mean of 79.40 and relative shoot dry weight (RSDW) ranged from 26.57-192.66 with an average of 69.29. Relative root : shoot ratio showed a range of 0.59 to 2.51. On the basis of relative performance of root-shoot dry matter, dry leaves weight, root-shoot ratio, six genotypes were found highly tolerant, seven were moderately tolerant, sixteen were moderately susceptible and six were highly susceptible to salinity stress. Based on visual observation of plants, relative shoot dry weight (RSDW), proline content, total sugar and soil plant analysis development (SPAD) value the genotypes CB031, CB035, CB003, CB023, CB026, CB028, CB013, CB030, CB014, CB024, CB019, CB020 and CB002 were selected as tolerant for further evaluation and use in breeding work. Ann. Bangladesh Agric. (2022) 26 (2) : 19-31

Trichoderma asperellum suppresses viral diseases and promotes the growth and yield of country bean

Viral diseases are the main adversaries of country bean (Lablab purpureus Lin.) production in Bangladesh. Potyviruses and cucumber mosaic virus (CMV) have been reported in country bean leaves that displayed virus-like symptoms. This study looked at the growth and yield of country bean plants that had been treated with Trichoderma asperellum to control country bean viruses. T. asperellum-treated plants exhibited decreased disease incidence up to 91% and a drop in the vector population up to 96%, when compared to control plants. Plant growth was enhanced in soil drenched with T. asperellum suspension, with an increase in the number of leaves per plant, pods per plant, root length, weight of dried pods/plant, and weight of dried seeds/plant. Finally, our findings suggest that T. asperellum could be an effective treatment for controlling viral diseases of the country bean in Bangladesh.

Evaluation of insecticides against bean pod borer and its larval parasitoid, Tachinid fly

In the field, insecticides were applied to observe the pod borer infestation rate and the infested pods with pod borer larvae were incubated in the laboratory to investigate the emergence of parasitoid, Tachinid fly. Emamectin benzoate 5 SG, Fenitrothion 50 EC and Neemoil (Fresh) found effective to control pod borer infestation. Emamectin benzoate 5 SG and Esfenvalerate 5 EC found safe after control for parasitoids while Curtap 50 SP and Fenvalerate 20 EC found toxic. However, maximum parasitism was recorded from control (89.78%) followed by Esfenvalerate 5 EC (88.00%), Cypermethrin 10 EC (85.72%), Emamectin benzoate 5 SG (84.56%), Fenitrothion 50 EC (81.75%) and Fresh Neemoil (79.26%). So, Emamectin benzoate 5 SG, Fenitrothion 50 EC and Fresh Neemoil can be considered for successful country bean cultivation that provide least infestation by bean pod borer and reasonable parasitism of Tachinid fly parasitoid after untreated control.

Growth, Yield and Profitability of Summer Country Bean (Lablab Purpureus L.) As Influenced by Exogenous Application of Plant Growth Regulators

A field experiment on summer country been (var. BARI Shim-7) was conducted at the Research Field of Plant Physiology Section of Horticulture Research Center, Bangladesh Agricultural Research Institute (BARI), Gazipur, during the summer season of 2018 and 2019 to study the effect of exogenously applied plant growth regulators (PGRs) on growth, yield and profitability of the crop. The experiment was consisted of four levels of NAA (15, 30, 45 and 60 ppm), three of CCC (200, 300 and 400 ppm), two of GA3 (20 and 30 ppm) and tap water as control. Average results of two years showed that all growth regulators performed better in respect of all characters studied over control. At 1st fruit set vine length (3.15 m) and number of leaves/plant (327.96), at last harvest stem girth (24.53 mm) and vine length (4.89 m), and plant dry matter (17.24%), number of pods/cluster (6.41), pod length (8.78 cm), number of pods/plant (351.30), individual pod weight (6.26 g) and pod set (38.13%) were the maximum in 60 ppm NAA followed by 45 ppm NAA and 200 ppm CCC. The maximum mean pod yield (10.65 t/ha) was obtained with the application of 60 ppm NAA closely followed by 45 ppm NAA (10.50 t/ha). Application of 200 ppm CCC also produced higher pod yield (8.75 t/ha) than that of control. Application of 60 ppm NAA also gave the maximum gross return (Tk. 532500/ha), gross margin (Tk. 3361248/ha) and BCR (3.11).&#x0D; Bangladesh J. Agril. Res. 47(1): 13-22, March 2022

Using Some Promising Insecticides as A Management Tool Against The Major Sucking Pests of Country Bean

An experiment has been conducted to know the efficiency of some promising pyrethroids and bio-rational insecticides for controlling the major sucking pests of country beans under field conditions during the winter season September 2020 – March 2021. The different treatments were Cypermethrin 10 EC (T1), Lambda-Cyhalothrin 2.5 EC (T2), Emamectin benzoate 5 SG (T3), Abamectin 1.8 EC (T4), Spinosad 45 SC (T5), and untreated control (T6). The rate of leaf infestation at the lower, middle, and top stages of country bean ranged from 8.82–17.78, 13.89–36.39, and 13.72–33.33% in T5treated and untreated control plots, respectively. The rate of shoot infestation at the middle and top stages of country bean ranged from 18.67–34.33 and 17.00–39.27% in T5 treated and untreated control plots, individually. The lowest and highest inflorescence infestation of 29.15% and 46.67% was recorded in T5 treated and untreated control plots, separately.The lowest fruit infestation of 8.84% by number and 8.32% by weight was recorded in the treated plot T5. The rate of reduction of pod infestation over control was 48.58, 24.02, 23.39, 21.81, and 19.92% by number and 73.53, 61.76, 58.82, 52.94, and 41.18% by weight in the treated plot T5, T4, T1, T3, and T2, respectively. The yield in different treatments ranged from 1.35-2.50 t ha-1. The highest adjusted net return and BCR of Tk. 52220.00 and 2.42, respectively were obtained from T2 treated plots. The second highest BCR of 2.16 was calculated from T4 treated plot. The lowest BCR of 1.05 was found in T2 treated plot. The treatments T5, T4, and T3 were effective to suppress the major sucking pests of the country bean.

Analysis of qualitative and quantitative morphological traits related to yield in country bean (Lablab purpureus L. sweet) genotypes

Country bean is a grain legume extensively farmed for its multi-purpose uses, yet the traits related to yield are are poorly studied and yet unexplored. A study on the diversity of qualitative and quantitative morphological characteristics concerning yield among the country bean germplasms collected from Bangladesh identified considerable variation in the studied traits across the germplasms and identified a complex correlation between the qualitative and quantitative traits. Principal Component Analysis (PCA) detected five components that contributed 66.38% qualitative traits and six components contributed 74.49% quantitative traits to total variations. Eigenvalues indicated that a majority of color-related qualitative traits included cotyledon, leaf, vein, seed, flower, and petals contributed, in contrast,a majority of the seed, leaf, flower, and inflorescence-related quantitative traits contributed to the total diversity of the Lablab germplasms. Among the quantitative traits, the highest coefficient of variation (CV%) was found in average pod weight (50.98%), followed by the total number of spikes per plant (43.82%), while seed length, pod weight, length, width, thickness, number of flower/spike, spike length, and total no of spikes/plant all had more than 20.00 percent CV, suggesting suitability to use in the breeding of high yielding genotypes. The germplasms are grouped into four and three clusters based on quantitative and qualitative traits, suggesting quantitative characters offer better clustering of genotypes. Considering the above traits, our research found that the BD-10804, BD-10807, BD-11091, BD-10808, BD-10815, and BD-11089 and cultivar Goal Goda Lablab beans germplasms produced higher pod weight with corresponding higher pod length, width, and thickness suggesting to use them as high yielding genotypes for food and fodder purposes.

Farmers’ Perceptions and Knowledge of Country Bean (Lablab purpureus L.) Insect Pests, and Diseases, and Their Management Practices, in Bangladesh

Country bean (Lablab purpureus L.), a popular vegetable in Bangladesh, is severely affected by insect pests and diseases. Farmers’ perceptions of insect pests, diseases, and their management are critical constraints to the establishment of an effective and sustainable pest management approach for this crop. A comprehensive survey was conducted with 300 country bean farmers from six districts of Bangladesh to assess farmers’ perceptions and knowledge of the insect pests and diseases of country bean, and their management practices. The survey results show that country bean farmers have been facing varying pest problems for more than ten years. They could identify eight pests and only one beneficial insect species in their fields, including thrips and jute weevil, as new pests. Among the pests, aphids and pod borers were common in all surveyed areas. More than 80% of farmers said their bean plants were severely affected by bean yellow mosaic virus and white mold diseases. Farmers also mentioned that insect pests and diseases together caused 30–40% yield losses of this crop. About 76% of the farmers solely depended on different chemical pesticides for the production of country bean. Growers frequently used insecticides from the organophosphorus and neonicotinoid groups, and fungicides from the triazole group, to manage pests associated with this crop. Farmers start applying pesticides from the seedling stages, at three-day intervals, maintaining only two- to four-day pre-harvest intervals (PHI). Our findings provide insight into the importance of developing sustainable pest management approaches for country bean production in Bangladesh.

First report of web blight of Lablab purpureus caused by Rhizoctonia solani AG‐5 in Bangladesh

Lablab purpureus (country bean, hyacinth bean) is one of the important winter-season legume vegetables in Bangladesh. In October 2020, a new disease was observed in the vegetative stage of country bean crop in a research field of Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh. Several farmers’ fields were subsequently surveyed in districts of Gazipur for bean diseases and similar symptoms were observed. Initial symptoms included water-soaked lesions that expanded rapidly and coalesced into a scalded appearance. As the symptoms progressed, the leaves became brown and necrotic leading to premature defoliation (Figure 1). Near the margin and petiole of the diseased leaves, a whitish mycelial growth was observed (Figure 2). Microscopy of the infected tissue revealed the typical morphological characteristics of Rhizoctonia: colourless septate hyphae, a right-angled branching pattern, multinucleated hyphal cells, and constriction of the hyphae near their point of origin (Sneh et al., 1994). The prevalence of the disease in the surveyed area was 70–80%. For isolation of the pathogen, diseased tissues were surface sterilised using 70% alcohol for 30 seconds and 2% sodium hypochlorite for 30 seconds (Prova et al., 2018). Samples were then washed in distilled water and placed on water agar media and incubated at 27°C. After 24 hours, emerging mycelia from the margin of the diseased tissues were transferred to potato dextrose agar (PDA). After seven days, white to brown mycelial growth radiated over the entire culture plate, with the formation of a ring of micro-sclerotia on the edge of the plate within 14 days. Prominent dark brown sclerotia (0.9–3.1 × 0.4–2.5 mm) were observed. To determine the number of nuclei, hyphal cells were stained with an alkaline safranin solution (0.5% of safranin, 10 ml of KOH 3%, 5 ml of glycerin and 79 ml of distilled water) as described by Sneh et al. (1994). The isolate had multinucleate hyphal cells, hypha branched at right angles, and moniloid cell formation occurred before sclerotia formation (Figure 3). To confirm the identity of the causal agent, DNA was extracted from two representative fungal isolates and the internal transcribed spacer (ITS) region of ribosomal DNA was amplified using primers ITS4 and ITS5, and sequenced (Islam et al., 2021). The resulting ITS sequence had the greatest identity (97%) with Rhizoctonia solani AG-5 nucleotide sequences (GenBank Accession Nos. OM039414.1, OM039416.1, MZ379610.1 and MW999177.1) using BLAST, and was deposited in GenBank (ON553688 - ON553689). Five country bean plants with two-three trifoliate leaves (cv. Bu Seem 2) were used to test the pathogenicity of the isolates (Figure 4). Agar blocks from seven-day-old cultures were placed onto superficially wounded leaves. Uninoculated PDA blocks were used on control plants. Inoculated plants were incubated in a moist chamber and water-soaked necrotic lesions appeared both on leaves and stems three days after inoculation. Five days post inoculation, leaves showed severe necrosis and died, resembling the symptoms found in the field. The pathogen was re-isolated from the plants and the re-isolated fungal isolates were morphologically similar to Rhizoctonia solani. Although infection of anastomosis group (AG)-A and AG-4 of binucleate Rhizoctonia on different bean species (Glycine max, Phaseolus vulgaris and Vigna unguiculata) has been recorded (Yang et al., 2005; Yang et al., 2007; Quadros et al., 2021), this is the first report of Rhizoctonia solani AG-5 infection on Lablab purpureus to our knowledge in Bangladesh and worldwide. The authors are thankful to the Research Management Wing of Bangabandhu Sheikh Mujibur Rahman Agricultural University, Bangladesh, for their support.

A Review on the Management of Country Bean (&lt;em&gt;Lablab purpureus&lt;/em&gt; L.) Diseases in Bangladesh

Purpose: Country bean (Lablab purpureus L.) is an important pulse crop consumed as a vegetable in the central and south-western regions of Bangladesh after eggplant and taro. It promises to ameliorate nutritional demand from vegetables and has an excellent possibility for the world market. But the production is hampered due to infection of several diseases in field conditions. Research method: This study was undertaken based on secondary data of existing literature from Bangladesh and other parts of the world. So far, many research works were done on this issue but those were not available to the policy makers, extension workers, and public in a systematic manner to date. Findings: In this paper, we tried to bring forth different aspects of phytopathological problems of country bean. It usually undergoes stresses from different soilborne to seed-borne pathogens and expresses symptoms from the seedling stage to maturity. Crop protection largely depends on the integration of host plants, seeds, agronomic practices, environmental footprints, and the use of appropriate agrochemicals based on the epidemiology of target pathogens. Here, we also described effective management strategies against respective pathogens of the diverse category. These microorganisms attack at different stages of crop growth and can affect the host plants enormously to cause maximum yield loss. Research limitations: The study focused on the management of country bean diseases based on biological and chemical approaches. It presents limited information on specific technologies in different agroecological zones. Originality/Value: This study identified research gaps among Bangladesh and other countries. It also provides information to combat country bean diseases to the economic threshold level for ensuring sustainable crop yield.

Development of biorational management package of root knot nematode disease of country bean

A field experiment was conducted with a view to test the efficacy of Tricho-composts and integration of Tricho-composts, poultry refuse (PR), neem oilcake (NOC), saw dust burning (SDB) with chemical nematicide Furadan 5G (Carbofuran) for controlling root knot nematode of country bean through which growers will be benefited. The root-knot nematode infested soils were treated with Tricho-compost-1 @ 2 kg/pit, Tricho-compost-2 @ 2 kg/pit, Tricho-compost-1 @ 2 kg/pit + Furadan 5 G @ 20 g/pit, Tricho-compost-2 @ 2 kg/pit + Furadan 5 G @ 20 g/pit, poultry refuse @ 5-6 kg/pit + Furadan 5 G @20 g/pit , neem oil cake @ 500 g/pit + Furadan 5 G @ 20 g/pit and saw dust burning + Furadan 5 G @ 20 g/pit. It was revealed that all the treatments performed well in reducing root-knot nematode infestation and increasing plant growth and yield country bean compared to farmers’ practices. Among the treatments, integration of poultry refuse with Furadan 5G or Trichoderma based bio-fungicides Tricho-composts with Furadan 5G or neem oil cake with Furadan 5G are the best treatments in reducing root-knot nematode infestation and increasing plant growth as well as yield of country bean. Soil treatment with only Tricho-composts or integration of saw dust burning with Furadan 5G also performed better in reduction of root knot nematode disease and increasing plant growth as well as yield of country bean.

Development of Biorational Management Package of Root Knot Nematode Disease of Country Bean

A field experiment was conducted with a view to test the efficacy of Tricho-composts and integration of Tricho-composts, poultry refuse (PR), neem oilcake (NOC), saw dust burning (SDB) with chemical nematicide Furadan 5G (Carbofuran) for controlling root knot nematode of country bean through which growers will be benefited. The root-knot nematode infested soils were treated with Tricho-compost-1 @ 2 kg/pit, Tricho-compost-2 @ 2 kg/pit, Tricho-compost-1 @ 2 kg/pit + Furadan 5 G @ 20 g/pit, Tricho-compost-2 @ 2 kg/pit + Furadan 5 G @ 20 g/pit, poultry refuse @ 5-6 kg/pit + Furadan 5 G @20 g/pit , neem oil cake @ 500 g/pit + Furadan 5 G @ 20 g/pit and saw dust burning + Furadan 5 G @ 20 g/pit. It was revealed that all the treatments performed well in reducing root-knot nematode infestation and increasing plant growth and yield country bean compared to farmers’ practices. Among the treatments, integration of poultry refuse with Furadan 5G or Trichoderma based bio-fungicides Tricho-composts with Furadan 5G or neem oil cake with Furadan 5G are the best treatments in reducing root-knot nematode infestation and increasing plant growth as well as yield of country bean. Soil treatment with only Tricho-composts or integration of saw dust burning with Furadan 5G also performed better in reduction of root knot nematode disease and increasing plant growth as well as yield of country bean.

Assessment of Allelopathic Potential of Selected Legume Leaf Extracts on Seedling Growth of Raphanus sativus L.

The aim of the present investigation was to assess the allelopathic potential of 25 Bangladeshi legume plants against the seedling development of the allelopathic-sensitive plant Raphanus sativus L. Five distinct concentrations of these plant species' aqueous leaf extracts viz., 1:05, 1:10, 1:15, 1:20, and 1.25 (w/v) were employed. Every time, distilled water (with no extract) was acted as a control, and the bioassay test was repeated three times. The inhibitory actions relied on concentration and the shoot growth was less responsive to plant extracts than the root development. The shoot growth of R. sativus was less inhibited (70%) by lentil (Lens culinaris) leaf extract whilst African dhaincha (Sesbania aculeate L) at concentration of 1:05 (w/v) provided the highest inhibition (100%). At a concentration of 1:10 (w/v), the root of Krishnochura (Delonix regia), Sada koroi (Albizia procera), Radhachura (Peltophorum pterocarpum), Minjiri, (Cassia siamea), Polash (Butea monosperma), Ipilipil (Leucaena leucocephala), Tripatri shak (Desmodium triflorum), Country bean (Lablab purpureus), Black gram (Vigna mungo), Ground nut (Arachis hypogae), Yardlong bean (Vigna unguiculata) and African dhaincha (Sesbania rostrata) exhibited the highest level of inhibition (100%) while Bokful (Sesbania grandiflora), had the lowest level of inhibitory activity (87%) at the same concentration. Comparing root growth inhibition (ranged 56–81%) to shoot growth inhibition (ranged 37–77%), the aqueous leaf extracts of legume plants demonstrated a lower level of inhibition on shoot growth. Lentil (Lens culinaris) provided the lowest average inhibition (37%) on the development of R. sativus shoots and Faba bean (Vicia faba) provided the greatest average inhibition (77%). Meanwhile, Tripatri shak (Desmodium triflorum), a herb legume, provided the least average inhibition (56%) on the root development of R. sativus (56%) and Winged bean (Psophocarpus tetragonolobus) offered the greatest (81%) level of inhibition. Compared to the categories of legume species the shrubs had the most limitation on the growth of R. sativus shoots (65%), whereas herb species had the least (60%) of this effect. However, the tree species had the most root growth inhibition (70%) while the herb species had the lowest (68%). According to the findings, African dhaincha (Sesbania rostrata), followed by Soybean (Glycine max), Faba bean (Vicia faba), Blackgram (Vigna mungo), and Winged bean (Psophocarpus tetragonolobus), are prospective candidates among the examined legume plant species that have substantial allelopathic features and may be used for further allelochemical extraction and characterization.