Pulses constitute an important component of the Indian food system by providing a major source of dietary protein and contributing to soil fertility through biological nitrogen fixation, thereby supporting sustainable agricultural production. Continuous research and development efforts have led to a steady increase in pulse production in the country, with their share in total food grain production rising from 5.63% in 2000-01 to 8.85% in 2017-18 (Directorate of Pulses Development, 2018). Despite this progress, productivity of several pulse crops remains below their potential, particularly in regions where adoption of improved technologies is limited.
       
Among the major pulse crops, black gram (Vigna mungo L.), popularly consumed as ‘dal’, occupies a prominent position due to its short duration, wide adaptability and suitability in multiple cropping systems. In Punjab, black gram is predominantly cultivated during the Kharif season, especially in districts such as Hoshiarpur, Amritsar and Gurdaspur (Kaul et al., 2020). However, the crop occupies only about 0.03% of the total cropped area of the state and its productivity remains considerably low compared to its potential yield. Enhancing black gram cultivation is therefore crucial for promoting crop diversification, improving soil health and strengthening nutritional security in Punjab.
       
Cluster frontline demonstrations (CFLDs) have been widely recognized as an effective extension approach for showcasing the production potential of improved technologies under farmers’ field conditions and for bridging the gap between research and practice. In addition to sub-optimal agronomic practices, insect pest infestation remains a major constraint to black gram productivity. The crop is attacked by a complex of insect pests including whiteflies, jassids, aphids, thrips, Maruca vitrata and Spodoptera litura, which cause substantial yield losses if not managed timely. While earlier CFLD studies on black gram have largely focused on yield enhancement and economic benefits, systematic documentation of insect pest population dynamics under CFLDs has received limited attention, particularly in Punjab. Understanding the temporal occurrence and stage-specific abundance of insect pests is essential for developing effective, need-based pest management strategies.
       
Hoshiarpur district, located in the sub-mountainous zone of Punjab, is characterized by small holder farming systems, declining soil fertility and frequent pest outbreaks, making it a suitable location for evaluating integrated production and protection technologies. To strengthen the assessment of pest dynamics, Kapurthala district of Punjab state was also included as a comparative site to capture location-specific variations under similar agro-climatic conditions.
       
In view of these gaps, the present study was undertaken by Punjab Agricultural University-Krishi Vigyan Kendra (KVK), Hoshiarpur, to evaluate the impact of cluster frontline demonstrations on yield, economics and insect pest population dynamics of Kharif black gram. The study aims to generate location-specific, evidence-based recommendations for improving productivity, profitability and pest management in black gram cultivation under Punjab conditions.

The study was carried out in different blocks of Hoshiarpur district during the Kharif seasons of 2020-2021 to 2022-23. Demonstrations were organized on a total of 40 ha involving 114 farmers, with different farmers selected each year to ensure wider coverage. Each participating farmer was carefully guided and trained in improved package of practices for black gram cultivation through off-campus training programmes.
       
For comparison, the farmer’s practice (FP) plots represented the local standard check, where farmers typically used local varieties such as Himmash, applied sub-optimal fertilizer doses and often sprayed unrecommended insecticides without proper seed inoculation. In contrast, the frontline demonstration (FLDs) plots followed an integrated crop management approach strictly as per the package of practices recommended by Punjab Agricultural University (PAU), Ludhiana. These included soil testing, use of bio-fertilizers, balanced fertilization, weed management and integrated pest and disease management.
       
The variety used in FLD plots was Mash 114, with a seed rate of 8 kg acre^-1 and an optimal sowing window between July 15 and July 25. Sowing was carried out using drill, kera, or pora methods at a depth of 4-6 cm with 30 cm row spacing. Seeds were treated with Rhizobium (LUR 6) biofertilizer before sowing. Fertilizers were applied based on soil test recommendations, with 11 kg urea and 60 kg single superphosphate per acre applied at sowing. Weed management included application of imazethapyr 10 SL @ 300 ml acre^-1 in 150 L water at 15-20 days after sowing, followed by one manual weeding/interculture operation about one month after sowing. The crop was predominantly rainfed, with one life-saving irrigation provided during prolonged dry spells when required. Integrated pest management included application of homemade PAU neem extract (1 L acre^-1) against whiteflies, jassids, aphids and pod-sucking bugs, while Ekalux 25 EC @ 500 ml acre^-1 in 100 L water was applied, when required, for hairy caterpillar management.
 
Experimental design
 
Since Demonstrations were non-replicated field experiments but large-scale demonstrations under farmers’ field conditions, the layout followed a cluster demonstration design (non-replicated). However, to maintain reliability, each demonstration was established on a minimum area of one acre per farmer across multiple locations, thereby ensuring wide-scale representativeness. Farmers’ practice plots located in the same villages served as comparative controls.
 
Pest observation and data recording
 
The population dynamics of major insect pests of black gram including whiteflies, jassids, aphids, thrips, Maruca vitrata larvae and Spodoptera litura larvae were recorded at weekly intervals during the 30^th to 38^th Standard Meteorological Weeks (SMW). For sucking pests (whitefly, jassid, aphid), counts were taken per three leaves per plant, while thrips incidence was recorded per five flowers. Pod borers (M. vitrata and S. litura) were recorded as larvae per plant. In addition to Hoshiarpur, pest dynamics were also monitored in the neighboring district of Kapurthala for comparative analysis of location-specific trends.
 
Data analysis
 
Grain yield data were obtained through crop cutting, while economic parameters were calculated based on prevailing market prices and cost of cultivation. Pest population data were pooled over farmers’ fields for each week and location and expressed as mean values. Since the demonstrations were non-replicated, formal statistical analyses such as analysis of variance were not applied. Although demonstrations were non-replicated, pooled yearly data were used to compute descriptive statistics (mean± standard error) to indicate variability. Instead, comparative analysis between Demonstrated plots (DP) and Farmer Plots (FP) was used to interpret treatment effects, with seasonal mean values employed to describe trends in pest population dynamics. Technology gap, extension gap and technology index were calculated following the formulas of Samui et al., (2000).

Technology Gap = Potential yield - Demonstration plot average yield

Extension Gap = Demonstration plot average yield - Farmer’s plot average yield

Where,
P= Potential yield of the crop.
D= Average demonstration plot yield of the crop.
       
Extension activities such as group meetings, kisan goshties and field days were conducted at the demonstration sites to disseminate results and encourage farmer-to-farmer learning. Feedback was systematically collected to refine future extension programmes.

The crops grown under demonstration plots were regularly monitored throughout the cropping season by scientists of Krishi Vigyan Kendra, Hoshiarpur. Observations were recorded on yield performance, economic returns and incidence of major insect pests. Grain yield data were further used to compute indicators such as technology gap, extension gap and technology index to assess the effectiveness of improved production technologies under Cluster Frontline Demonstrations (CFLDs).
 
Yield and yield increase
 
Over three consecutive Kharif seasons (2020-21 to 2022-23), the yield performance of a crop variety was evaluated across different years and areas. The study covered an area of 10 hectares in the first two years and expanded to 20 hectares in 2022-23. The yield under demonstration plots (DP) consistently outperformed farmers’ practice (FP), with yields increasing from 7.10 q ha^-1 in 2020-21 to 7.25 q ha^-1 in 2022-23 (Table 1). The corresponding yield increases were 32.71%, 30.94% and 26.09% across the three years, reflecting an effective adoption of improved practices. However, the technology gap ranged between 1.75 and 1.90 q ha^-1, while the extension gap decreased from 3.65 to 3.25 q ha^-1. The technology index varied slightly, with a range of 19.44% to 21.0%, (Table 1) indicating areas for further refinement in technology dissemination and adoption to maximize yield potential. Similar results were also reported by Kaul et al., (2020) in Mash 114 variety i.e. the higher yield was observed under FLDs than check. Sanjeev Kumar et al., (2017) carried out studies on the impact of frontline demonstrations on the production and productivity of moong (Vigna radiata L), mash (Vigna mungo L), rajmash (Phaseolus vulgaris L), lentil (Lens culinaris L) and chickpea (Cicer aeritinum L),  and recorded higher yields in demonstration field than following farmer’s practices. Similar results were documented by Kumari and Singh (2023) where higher yield (17.80 q ha^-1) was recorded under demonstrated technology in comparison to farmer’s practice (14.70 q ha^-1)  in chickpea under two year’s study trials in Kapurthala district. The adoption of improved cultivation technologies like sowing method, weed control, fertilizer application according to recommended package of practices resulted in increased yield in demonstration plot as compared to check. A study by Matharu and Tanwar (2018) also registered higher yields in demonstration plot as against the farmer’s practice. The yield enhancement observed under FLDs through the adoption of improved production technologies is consistent with earlier reports (Kumar et al., 2016; Vedna, 2007; Sharma et al., 2012).


 
Economic returns
 
The economic analysis of Mash cultivation over three Kharif seasons (2020-2023) reveals a comparative evaluation between farmers’ practice (FP) and demonstration plots (DP) (Table 2). The average cost of cultivation was slightly lower for DP, ranging from Rs 29,154 to Rs 30,993 ha^-1, compared to Rs 30,448 to Rs 31,972 ha^-1 for FP. Despite the lower costs, DP consistently achieved higher average gross returns, increasing from Rs 38,500 to Rs 42,213 ha^-1, compared to Rs 31,500 to Rs 34,560 ha^-1 for FP. Consequently, the average net returns for DP were significantly higher, with increases ranging from Rs 8905 to Rs 11,220 ha^-1, compared to Rs 1,052 to Rs 2,588 ha^-1 for FP. This economic advantage is reflected in the benefit-cost (B: C) ratio, which was consistently higher for DP, ranging from 1.26 to 1.36, compared to 1.03 to 1.08 for FP. These results underscore the economic viability and profitability of adopting improved cultivation practices for Mash, as demonstrated by the higher returns and better cost efficiency achieved under the demonstration plots. Overall, the highest B: C ratio was worked out under demonstration plot i.e., 1.30. Dwivedi et al. (2019) also revealed higher monetary returns under demonstrations due to the application of recommended cultivation practices.


 
Population dynamics of different insect pests of Kharif mash
 
The weekly mean incidence (three-year average-Table 3, Fig 1) of major insect pests of Kharif mash at Hoshiarpur and Kapurthala revealed clear differences between the two locations. Among sucking pests, whiteflies recorded the highest mean population, being slightly higher at Hoshiarpur (3.65 per three leaves) than at Kapurthala (3.42 per three leaves). Jassid incidence was almost comparable between the sites (2.15 vs. 2.24 per three leaves), whereas aphid populations remained relatively low, ranging between 1.26 and 1.35 per three leaves. Thrips infestation was moderate at both locations, with marginally higher incidence at Kapurthala (0.72 per 5 flowers) compared to Hoshiarpur (0.66 per 5 flowers). Among pod borers, Maruca larvae averaged 0.53 per plant at Hoshiarpur and 0.61 per plant at Kapurthala, while Spodoptera litura larvae showed slightly higher incidence at Kapurthala (0.80 per plant) than at Hoshiarpur (0.74 per plant). Overall, the data suggest that whitefltes and jassids were the predominant pests at both the sites, while pod borers (M. vitrata and S. litura) were observed at relatively lower levels, with Kapurthala tending to support slightly higher populations of chewing pests. Overall, whiteflies and jassids emerged as the predominant pests across both locations, while pod borers occurred at comparatively lower levels, indicating location-specific variation in pest abundance (Kaul et al., 2020).




 
Pod damage due to major insect pests
 
The data presented in Table 4 indicate that pod damage caused by M. vitrata and S. litura was consistently lower in demonstration plots compared to farmers’ practice during all three Kharif seasons. Pod damage by M. vitrata ranged from 10.9 to 12.4% under farmers’ practice, whereas it  reduced to 5.7-6.8% under demonstration plots. Similarly, pod damage due to S. litura was recorded in the range of 8.3-9.6% in farmers’ practice, which declined to 4.1-4.9% under demonstration plots. The reduction in pod damage can be attributed to timely monitoring of pest incidence and adoption of need-based plant protection measures under recommended production practices (Kaul et al., 2020). Lower pod damage during the reproductive stage directly contributed to improved yield performance in demonstration plots.


 
Association of crop growth stages with insect pest incidence
 
Table 5 shows a clear association between crop growth stages of Kharif black gram and the incidence of major insect pests. Sucking pests such as whiteflies and jassids predominated during the seedling to vegetative and branching stages, while thrips incidence increased during the flowering stage. Pod borers, particularly M. vitrata and S. litura, appeared mainly during the pod formation stage, which represents the most critical period for yield loss. This stage-specific occurrence of pests highlights the importance of phenology-based pest management strategies for effective control in black gram, as also reported earlier in pulse crops (Kaul et al., 2020).


 
Pest management interventions followed
 
Need-based pest management interventions were adopted in the demonstration plots based on regular field scouting and observed pest incidence. On average, two insecticide sprays were applied during the crop season. The first spray was generally applied during SMW 35-36, coinciding with the increase in sucking pest population, particularly whiteflies and jassids, while the second spray was undertaken during SMW 37-38 to manage pod borers (M. vitrata and S. litura) at the pod formation stage. In contrast, farmers’ practice involved either delayed or indiscriminate insecticide application without considering pest population levels or crop growth stage. Timely and stage-specific application of plant protection measures under demonstration plots contributed to lower pest incidence and reduced pod damage.
 
Adoption of technology and farmer feedback
 
Feedback collected from participating farmers indicated a high level of acceptance of the demonstrated technologies. About 82-88% of farmers expressed willingness to continue the recommended practices in subsequent seasons due to visible improvement in crop performance and reduction in insect pest incidence. Farmers perceived a notable reduction in sucking pests and pod borers, particularly during the flowering and pod formation stages. The major constraints reported were timely availability of quality seed, rising cost of plant protection chemicals and occasional difficulty in identifying pest incidence at early stages. Overall, positive farmer perception reinforced the effectiveness and adoptability of the demonstrated practices.
 
Integrated interpretation of pest damage, crop stage and pest dynamics
 
The combined assessment of pod damage percentage, crop growth stage-pest association and weekly pest dynamics provides a clearer understanding of insect pest pressure in Kharif black gram. Reduced pod damage under demonstration plots confirms the effectiveness of timely interventions during critical crop stages. The stage-wise occurrence of pests indicates that sucking pests dominate during vegetative growth, whereas pod borers become prominent during pod formation, which is the most yield-sensitive stage. The pest dynamics graph further highlights that peak pest incidence consistently occurred during SMW 36-38, emphasizing this period as the most critical window for pest management. Integration of these parameters strengthens the interpretation of results and supports stage- and time-specific pest management strategies for sustainable black gram production.

The study demonstrated that adoption of recommended production and pest management practices through Cluster Frontline Demonstrations significantly improved the productivity and profitability of Kharif black gram in Punjab. Demonstration plots recorded a consistent yield advantage of 26-33% over farmers’ practice, along with higher net returns and benefit–cost ratios. Progressive reduction in technology and extension gaps across seasons reflected improved adoption of recommended practices, although further scope exists to bridge the remaining yield gap. Seasonal monitoring revealed whitefly and jassid as the predominant pests during the vegetative stage, while pod borers (Maruca vitrata and Spodoptera litura) caused maximum damage during pod formation. Peak pest incidence during SMW 36-38 highlighted this period as the most critical for pest management. Reduced pod damage under demonstration plots confirmed the effectiveness of timely, stage-specific interventions. High farmer acceptance and willingness to continue the demonstrated technologies underline their practical relevance. Overall, integration of improved agronomic practices with need-based pest management offers a sustainable approach for enhancing black gram productivity and can be effectively scaled up in similar agro-ecological regions.

Authors declare there is no conflict of interest to disclose.