Co-friendly management of sucking insect and mite pest of yard long bean

Introduction

Yard long bean (Vigna unguiculata) is a nutritious green vegetable under the family of Fabaceae. Edible beans are a highly nutritious food, packed with protein, starch, minerals, and vitamins like folate, iron, potassium, and magnesium, as well as other important nutrients. Beans are low in total fat, salt, and cholesterol. Consuming a diet high in beans can enhance health by reducing the risk of heart disease, obesity, and several types of cancer due to their rich concentration of health-boosting nutrients. They are highly nutritious, boasting a significant amount of easily digestible protein in both the pods (23.5-26.3%) and the leaves (Ano and Ubochi 2008) [2] . It is also significant as a source of high-quality cattle fodder. It is also recognized for its contribution to residual nitrogen in soil (Leikam et al. 2007) [9] . Yard long beans are a nutritious vegetable, commonly cultivated during the kharif season, and are a good source of crucial vitamins. As a bean pod grows and develops, its seed tissues accumulate nutrients, especially protein and carbohydrates. Dry beans typically contain around 55-65% carbohydrates and 15-25% protein, along with notable amounts of iron and zinc (Mallillin et al. 2008) [11] . Dry beans are also a good source of B vitamins. When cooked, about 70-75% of the water-soluble vitamins in the beans are preserved (Celmeli et al. 2018) [6] . In the year 2020-2021, the crop occupied an area of 17680.08 hectares, and the production reached 33281.75 metric tons (BBS 2021) [3] . Farmers in Bangladesh continued using insecticides out of choice or experience because they either forgot or didn't care to follow the guidelines. The destructive effects of insecticides on people, animals, the environment, and helpful insects present a serious threat as a result. To solve this issue and safeguard both the environment and our way of life, eco-friendly management is required. One of the most efficient strategies for observing various insect species is the use of colored sticky traps (Bashir et al. 2014) [5] . Yellow sticky traps attract pests including whiteflies, aphids, leafhoppers, and leaf miners, while blue sticky traps mostly draw thrips. Recently, a variety of chemicals containing biopesticides have offered an environmentally friendly substitute for conventional chemical pesticides, and these are highly successful in reducing insect pests of yard-long beans.

Materials and Methods

The experiment was conducted from March 2022 to June 2022 in the central farm of Sher-e-Bangla Agricultural University, Sher-e-Bangla Nagar, Dhaka-1207. The yard long bean (Kagornatoki variety) seeds were used in the experiment which obtained from Bangladesh Agricultural Development Corporation (BADC), Dhaka. Ten treatments were used in the experiment such as T 1 = Blue sticky trap + Biomax 1.2 EC (Abamectin), T 2 = Blue sticky trap + Ecomec 1.8 EC (Abamectin), T 3 = Blue sticky trap + Biotrin (Matrin 0.5% AS), T 4 = Yellow sticky trap + Biomax 1.2 EC (Abamectin). T 5 = Yellow sticky trap + Ecomec 1.8 EC (Abamectin), T 6 = Yellow sticky trap + Biotrin (Matrin 0.5% AS), T 7 = White sticky trap + Biomax 1.2 EC (Abamectin), T 8 = White sticky trap + Ecomec 1.8 EC (Abamectin), T 9 = White sticky trap + Biotrin (Matrin 0.5% AS), and T 10 = untreated control. The experiment was conducted using a Randomized Complete Block Design (RCBD) with three replications. The unit plot size was 2.2 m x 1.8 m with a distance maintained between two blocks and two plots were 1.0 m and 0.5 m, respectively. Manures and fertilizers were applied such as cowdung, @ 7 kg, urea 7 kg, TSP 9 kg and MoP 11kg ha -1 . Intercultural operations are maintained by Irrigation, Weeding, Staking, Installation of colored sticky traps etc. Data were collected at seven days interval during the period of the experiment as following No. of sucking pests i.e. aphid, jassid, whitefly, thrips, mite /5 leaves,No. of aphids /5 pods,Total no. of leaves / plant,No. of infested leaves /plant,Total no. of flowers/ plant,Total no. of pods /plant, No. of healthy pods/ plant,No. of infested pods /plant ,Percent infestation of pod ,Yield data (t/ha). The marginal benefit cost ratio (MBCR) was calculated using the recent market prices of yard long bean. In the statistical analysis, the data for various characteristics were subjected analysis of variance (Anova) using statistical software Statistix-10. The mean values of all the characters were calculated and the Mean Differences were compared by TUKEY'S test at 5% level of significance.

Results and Discussion

Incidence of sucking insects and mites on leaves of yard long bean

The efficiency of various management strategies combining colored sticky traps with biopesticides showed significant variations in controlling sucking insects and red mite incidence per 5 leaves during the vegetative stage of yardlong bean, compared to the untreated control, as indicated in (Table 1). T 5 treatment was found very effective to control leafhoppers, aphids, whiteflies, and red mite pests. The lowest number of leafhoppers, aphids, whiteflies, and mites (4.43, 1.90, 1.49, and 3.66, respectively) per 5 leaves was observed in the T 5 treatment, followed by the T 4, T 6, and T 8 treatments. In contrast, the untreated control plot (T 10 ) exhibited the highest incidence of leafhopper, aphid, whitefly, and red mite pests (8.86, 6.73, 4.66, and 7.81, respectively) per 5 leaves, respectively, which was followed by T 3, T 1, and T 2 treatments (Table 1), respectively. At the 0.05 level of probability, means with similar letters in a column are statistically identical, whereas those with dissimilar letters differ considerably.

[T 1 =Blue sticky trap plus Biomax 1.2EC (Abamectin) at 1 milliliter L-1 of water; T 2 = blue sticky trap plus Ecomec 1.8 EC (Abamectin) at 1 milliliter L-1 of water; T 3 =blue sticky trap plus Biotrin (Matrin 0.5% AS) at 1.4 milliliter L-1 of water; T 4 = Yellow sticky trap + Biomax 1.2EC (Abamectin) @ 1 ml L-1 of water; T 5 = Yellow sticky trap + Ecomec 1.8EC (Abamectin) @ 1 ml L-1 of water, T 6 = Yellow sticky trap + Biotrin (Matrin 0.5% AS) @ 1.4 ml L-1 of water, and 0.5 ml L-1 of water T 7 =White sticky trap plus Biomax 1.2 EC (Abamectin) at 0.5 ml L-1 of water; T 8 = White sticky trap plus ecomec 1.8 EC (Abamectin) at 0.5 ml L-1 of water and T 9 =white sticky trap with Biotrin (Matrin 0.5% AS) at 1 ml L-1 of water ; and T 10 =untreated control].

Incidence of aphids and thrips on flowers of yard long bean

The effectiveness of several management strategies that combined biopesticides and colored sticky traps showed notable differences in reducing the prevalence of aphids and thrips per five blooms during the flowering stage of yardlong bean, compared to the untreated control, as shown in Table 2. The lowest number of aphids (3.43) per 5 flowers was observed in the T 5 treatment. In contrast, the treatment (T 2 ) was observed to be highly effective in suppressing thrips populations. The lowest number of thrips (5.38) per 5 flowers was found in the T 2 treatment, comprising T 1 (5.95 per 5 flowers) and T 3 (6.19 per 5 flowers). On the contrary,

International Journal of Agriculture and Food Science https://www.agriculturaljournals.com the highest incidence of thrips (12.16) per 5 flowers was observed in untreated control (T 10 ) plots. Sultana (2020) [14] observed that the greatest reduction in aphid population was achieved with Abamectin (79.02%), followed by Spinosad (73.95%) and Neem oil (69.22%) treatments on bean flowers.

Incidence of aphids on pods of yard long bean

The lowest number of aphid (3.93) per 5 pods in (T 5 ) treatment comprising by T 4 (4.05), and T 6 (4.11) treatments respectively. On the contrary, the untreated control plots (T 10 ) showed the highest incidence of aphid (12.82) per 5 pods followed by T 3 , T 1 and T 2 treatments (Figure 1). Uddin (2013) [17] reported that aphid are known to heavily infest yard long beans. Hossain et al. (2022) [7] suggested that aphid on beans can be monitored and suppressed by yellow sticky traps and biopesticides.

Percent leaf infestation by sucking insects and red mites on yard long bean

The significant variations observed in the effectiveness of various management tactics, particularly those integrated with colored sticky traps along with biopesticides, compared to the untreated control, emphasize the importance of implementing effective pest management strategies to reduce leaf infestation by sucking insects and red mites during the vegetative stage of yard-long beans, as illustrated in Table 3. The highest number of total leaves per plant (108.57) but the lowest percent of leaf infestation (24.54%) in the T 5 treatment, comprising T 4, T 6, and T 8 treatments. The (T 5 ) treatment reduced the highest percent (47.72%) of leaf infestation. On the other hand, the lowest number of total leaves per plant (82.40), but the highest percent of leaf infestation (46.94%), was observed in untreated control (T 10 ) plots, which was followed by T 3 , T 1, and T 2 treatments, respectively (Table 3). The lowest number of infested leaves/plants was found in T 5 (26.60). (Abamectin) @ 1 ml L-1 of water; T 5 = Yellow sticky trap + Ecomec 1.8EC (Abamectin) @ 1 ml L-1 of water, T 6 = Yellow sticky trap + Biotrin (Matrin 0.5% AS) @ 1.4 ml L-1 of water, and 0.5 ml L-1 of water T 7 =White sticky trap plus Biomax 1.2 EC (Abamectin) at 0.5 ml L-1 of water; T 8 = White sticky trap plus ecomec 1.8 EC (Abamectin) at 0.5 ml L-1 of water and T 9 =white sticky trap with Biotrin (Matrin 0.5% AS) at 1 ml L-1 of water ; and T 10 =untreated control].

Flower number and percent flower infestation by sucking insects on yard long bean

Table 4 shows that, when compared to the untreated control, there were notable differences in the efficacy of several control strategies that used colored sticky traps with biopesticides to manage sucking pests, such as aphids and thrips, during the blooming stage of yard-long beans. The T5 treatment had the greatest number of flowers overall (27.72) per plant but the lowest percentage of floral infestation (15.39%). This treatment included T 4 and T 6 treatments. The T 5 treatment also reduced the maximum flower infestation (73.22%). In contrast, the lowest number of total flowers per plant (22.87), but the untreated control (T 10 ) plots exhibited the highest percent of flower infestation (57.47%), which was followed by T 3 , T 1, and T 9 treatments, respectively. The T 9 treatment reduced the lowest percent of leaf infestation (49.64%) (Table 4). Sani (2017) reported that the legume flower thrips was the most significant pest of leguminous vegetables, which can be effectively controlled by using biopesticides as alternatives to synthetic chemical insecticides. At the 0.05 level of probability, means with similar letters in a column are statistically identical, whereas those with dissimilar letters differ considerably.

[T 1= Blue sticky trap plus Biomax 1.2EC (Abamectin) at 1 milliliter L-1 of water; T 2= blue sticky trap plus Ecomec 1.8 EC (Abamectin) at 1 milliliter L-1 of water; T 3= blue sticky trap plus Biotrin (Matrin 0.5% AS) at 1.4 milliliter L-1 of water; T 4 = Yellow sticky trap + Biomax 1.2EC (Abamectin) @ 1 ml L-1 of water; T 5 = Yellow sticky trap + Ecomec 1.8EC (Abamectin) @ 1 ml L-1 of water, T 6 = Yellow sticky trap + Biotrin (Matrin 0.5% AS) @ 1.4 ml L-1 of water, and 0.5 ml L-1 of water T 7 =White sticky trap plus Biomax 1.2 EC (Abamectin) at 0.5 ml L-1 of water; T 8 = White sticky trap plus ecomec 1.8 EC (Abamectin) at 0.5 ml L-1 of water and T 9 =white sticky trap with Biotrin (Matrin 0.5% AS) at 1 ml L-1 of water ; and T 10 =untreated control. ].

Yield of yard long bean

The highest yield of yard long bean (7.29 t per ha) was observed in (T 5 ) treatment comprising by T 4 (7.12 t per ha), and T 6 (7.03 t per ha) treatments. On the contrary, the lowest yield (5.13 t per ha) was observed in untreated control (T 10 ) plots which was followed by T 3 and T 1 treatments (Figure 2). In contrast, Rashid et al. (2022) [12] indicated that the highest yield was achieved through the combined application of Fimrite and Biotrin integrated with blue sticky trap to control thrips and mites on another crop chilli.

Marginal benefit-cost ratio (MBCR) in yard long bean production

The net profit and marginal benefit cost ratio in the case of yard long bean production are illustrated in (Table 5). The net return and marginal benefit cost ratio fluctuated based on the expense of biopesticide applications. The highest net return (Tk. 98100.00 per ha) was recorded from the T 5 treated plots, followed by the T 4 (Tk. 83300.00) and T 6 (Tk. 81050.00) treatments. The highest marginal benefit (MBCR 9.91) came from (T 5 ) treated plots, but due to higher costs, the MBCR of Biomax 1.2 EC (Abamectin) goes down to Biotrin. The second highest benefit (MBCR 7.79) was obtained from the (T 8 ) treated plots, which were followed by (T 6 ) (MBCR 5.81) and (T 4 ) (MBCR 5.14), respectively. The lowest MBCR (2.46) was found in the (T 1 ) treatment, followed by the (T 3) and (T 7 ) treatments, in which the MBCR was found to be 2.51 and 3.63, respectively.

Abamectin) @ 1 ml L-1 of water; T 5 = Yellow sticky trap + Ecomec 1.8EC (Abamectin) @ 1 ml L-1 of water, T 6 = Yellow sticky trap + Biotrin (Matrin 0.5% AS) @ 1.4 ml L-1 of water, and 0.5 ml L-1 of water T 7 =White sticky trap plus Biomax 1.2 EC (Abamectin) at 0.5 ml L-1 of water; T 8 = White sticky trap plus ecomec 1.8 EC (Abamectin) at 0.5 ml L-1 of water and T 9 =white sticky trap with Biotrin (Matrin 0.5% AS) at 1 ml L-1 of water ; and T 10 =untreated control.

Biomax 1.2 EC (Abamectin) /spray = Tk. 3200 /500 ml/ha, Ecomec 1.8 EC (Abamectin) /spray = Tk. 1100/500 ml/ha, Biotrin 0.5% AS/spray = Tk. 2450/700 ml/ha, 3 times sprayed /ha, 2 labors needed for per ha per spray, Labour wage for spraying pesticides = Tk. 500/day/labour (8 hours day), Trap (blue, yellow, white) = Tk. 40/ trap. Av. market price of edible yard long bean pod = Tk.50/kg.

Conclusion

The findings showed that in the case of the incidence of sucking insects and mites on the leaves of yard-long beans, the lowest number of leafhoppers, aphids, whiteflies, and mites was observed in the yellow sticky trap + Ecomec 1.8 EC (Abamectin) (T 5 ) treatment, followed by T 4 and T 6 treatments. On the contrary, the highest incidence of leafhopper, aphid, whitefly, and red mite pests was observed in untreated control (T 10 ) plots, which were followed by T 3,

T 1, and T 2 treatments, respectively. In case of incidence of aphids and thrips on flowers of yard-long bean, the lowest number of aphids was observed in the T 5 treatment, followed by T 4 and T 6 treatments. On the contrary, the highest incidence of aphids was found in untreated control (T 10 ) plots, which was followed by T 3 , T 1, and T 2 treatments. The highest number of total leaves, total flowers, and pods per plant was observed in the T 5 treatment, followed by the T 4 , T 6, T 8 , and T 7 treatments, respectively. On the contrary, the lowest number of total leaves, pods per plant, and leaf infestation was observed in untreated control (T 10 ) plots, which was followed by T 3 , T 1, and T 2 treatments, respectively. The highest yield of yard long bean (7.29 t per ha) was found in the T 5 treatment, followed by the T 4 (7.12 t per ha) and T 6 (7.03 t per ha) treatments. Conversely, the lowest yield (5.13 per ha) was found in the untreated control (T 10 ) plots. So T 5 treatment showed the best combination regarding the cost of production as well as a higher yield.

Acknowledgement

AcknowledgementsThe authors are obliged to the department of Entomology of Sher-e-Bangla Agricultural University (SAU), Dhaka-1207, Bangladesh.The Ministry of Science and Technology, Government of the peoples's Republic of Bangladesh has been applauded by the authors for providing financial support.

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