Efficacy of different bio-pesticides for the management of okra shoot and fruit borer (Earias vitella Fab.)

Introduction

Lady's finger (Abelmoschus esculentus L.), commonly known as okra or bhindi, is one of the most important vegetable crops grown in tropical and subtropical regions of the world because of its taste, flavour, and nutritional value. Okra is one of the widely consumed and commercially cultivated vegetable crops and forms an important component of the human diet due to its nutritional and medicinal properties. It is a very popular summer vegetable for home gardening, and it is also grown commercially throughout the world, especially in the Indo-Pakistan subcontinent (Yadav et al., 2024a) [17] A total of 204.61 million metric tons of vegetables are produced in India. India is the largest producer of okra in the world, producing 6,371,000 tonnes of okra during 2021-2022. Nigeria is the second-largest okra-producing country in the world, with a production of 1,837,904 tonnes. India, which ranks first, contributed approximately 62 percent of the world's total okra production. In 2022, the top three producing countries accounted for an 85.5 percent share, while the top ten countries accounted for 95.0 percent of global production. The major okra-producing states in India include Uttar Pradesh, Bihar, Odisha, West Bengal, Andhra Pradesh, and Karnataka (Anonymous, 2022) [2] . Okra is an important component of the human diet and is a good source of protein, carbohydrates, vitamins, calcium, potassium, enzymes, and total minerals, which are often deficient in the diets of developing countries. Okra is also good for health and the mucilage of okra has great medicinal properties: antioxidant, antidiabetic, antitumor, antimicrobial, and antiulcer capacities, and it also has the properties to control cholesterol in the human body (Yadav et al., 2024b) [14] . Its medicinal properties have been associated with the relief of haemorrhoids and ulcers. Okra has also been used medicinally as a blood volume expander and plasma replacement, and in the treatment of chronic dysentery, spermatorrhoea, and genito-urinary disorders. Its seeds are rich in unsaturated fatty acids and rich in fibre, which is good for digestion and cures ulcers of the digestive system (Yadav et al., 2024c) [13] . The nutritional and medicinal importance of okra fruits has increased interest in its commercial cultivation.

The composition of okra pods per 100 g of edible portion is as follows: water 88.6 g, energy 144.00 kJ (36 kcal), protein 2.10 g, carbohydrate 8.20 g, fat 0.20 g, fibre 1.70 g, Ca 84.00 mg, P 90.00 mg, Fe 1.20 mg, β-carotene 185.00 μg, riboflavin 0.08 mg, thiamin 0.04 mg, niacin 0.60 mg, and ascorbic acid 47.00 mg. It is crucial for human nutrition and a good source of total minerals, vitamins, calcium, potassium, enzymes and other nutrients that are frequently lacking in the diets of developing countries (Yadav et al., 2025a) [15] . Biopesticides, including entomopathogenic fungi and bacteria, offer promising, eco-friendly pest management options (Yadav et al., 2025b) [16] .

Materials and Methods

The present investigation on okra shoot & fruit borer (Earias vitella Fab.) using different bio-pesticides was carried out at the experiment, Organic Research Farm Kargua Ji, Department of Entomology, Institute of Agricultural Sciences, Bundelkhand University, Jhansi (Uttar Pradesh) during the Kharif season of 2022-2023. The experiment was laid out in a simple Randomized Block Design (RBD) with nine treatments, including the untreated control, Beauveria bassiana 2.0 kg/ha, Bacillus thuringiensis 2.0 kg/ha, Neem oil 5%, Metarhizium anisopliae 2.0 kg/ha, NSKE 5%, Verticillium lecanii 2.0 kg/ha, Karanj oil 10% and Garlic extract 10%. The individual plot size was 3.20 × 2.15 m, with row-to-row and plant-to-plant distances of 60 × 45 cm, respectively. Okra variety Kashi Lalima was sown on 25 July, 2022. All the biopesticides were applied as foliar sprays. The recommended package of practices was adhered to for cultivating the crop. Records were maintained regarding the percentage of shoots infested and the total damaged fruits, with shoot infestation computed at weekly intervals from five randomly selected plants in each plot. Fruit infestation data were collected from each picking, and marketable fruit yield was recorded. Data were recorded one day before spraying and on the 3 rd , 7 th , and 14 th days following each application. The collected data on different parameters were analyzed using analysis of variance (ANOVA) as per the method of Gomez and Gomez (1984). The results were analyzed using the 'F' test, and the critical difference (CD) was determined at a 5% significance level. The prevailing market price of okra, the cost of biopesticides, and labour charges were considered to calculate the cost-benefit ratio, evaluating the economics based on the net income obtained from the additional yield over the control. The percentage of shoot and fruit infestation was determined using the formula below:

Results and Discussion

The minimum shoot infestation (Table 1) after 1 st spray 6.83, 4.75, and 1.82 per cent was recorded in Beauveria bassiana @ 2 kg/ha treated plot at 3 rd , 7 th and 14 th days after spraying respectively followed by Bacillus thuringiensis 2 kg/ha (7.15, 4.93 ), all the treatments were found effective and significantly superior over the control at 3 rd , 7 th , and 14 th days after spraying respectively. This study substantiates with the findings of Ghosal et al. (2013), who reported that the biorational insecticide spinetoram 50 g a.i./ha has been found superior to other treatments against Earias vitella (Fab.) okra. It recorded 4.01 % mean shoot and fruit infestation in okra. The next effective treatment was emamectin benzoate @ 18 g a.i./ha (5.61 % mean shoot and fruit infestation in okra), followed by spinosad @ 75 g a.i./ha (5.87 %), chlorfenapyr@ 125 g a.i./ha (7.42 %), Bacillus thuringiensis (9.47 %) and azadirachtin (1 0.68 %). The results of the present study were in accordance with the findings of several workers (Mandal et al., 2007; Panbude et al., 2019) [6, 8] . The yields among the treatments were significant. The highest yield (Table 4) was recorded in T 1 Beauveria bassiana (150.20 q/ha), followed by T 3 Bacillus thuringiensis (148.6 q/ha), T 8 Neem oil (143.11 q/ha), T 4 Metarhizium anisopliae (142.5 q/ha), T 6 NSKE (139.84 q/ha), T 2 Verticellium lecanni (128.4 q/ha), T 7 Karanj oil (123.29 q/ha) and T 5 Garlic extract (117.40 q/ha) as compare to T 9 (87 q/ha). When the cost-benefit ratio was worked out, a good result was achieved. Among the treatment studied, the best and most economical treatment was T 1 Beauveria bassiana (1:3.10), followed by T 3 (1:3.05), T 8 (1:3.02), T 4 (1:2.93), T 6 (1:2.74), T 2 (1:2.65), T 7 (1:2.61), T 5 (1:2.48), as compared to control T 9 (1:1.90). The result of present study was according with the finding of Kaveri and Kumar (2020) observed that the Two applications of seven insecticides viz; Spinosad 45% SC, Metarhizium anisopliae, Verticillium lecanii, Beauveria bassiana, Neem oil 3%, karanjin 2% EC, Aloevera extract 1%, were evaluated against shoot and fruit borer, Earias vittella. Minimum per cent of shoot infestation, percent fruit infestation and B:C ratio were observed in Spinosad 45% SC (5.22%, 5.86% and 1:11.1), respectively, which was followed by Beauveria bassiana (11.63%, 12.33%, and 1:8.43) < untreated control (water spray) (24.37%, 24.35% and 1:4.22), respectively. Chandravanshi et al. (2018) observed that Beauveria bassiana @ 10 g/lit., Bacillus thuringiensis @ 2 g/lit., Metarhizium anisopliae @ 10 g/lit. Fipronil 0.3 G soil application after germination, followed by spray with Metarhizium anisopliae, was found to be most effective against okra shoot and fruit borer, as it was recorded overall less fruit infestation percentage (8.30%) highest fruit yield (89.89 q/ha), with a benefit-cost ratio of 1.38:1.00.

Conclusion

The present study demonstrated that all the tested biopesticides were effective and significantly superior to the control in reducing the infestation of okra shoot and fruit borer, Earias vitella. Among the treatments, Beauveria bassiana 2.0 kg/ha was found to be the most effective treatment, recording the lowest shoot and fruit infestation throughout the observations. It also resulted in the highest yield of 150.20 q/ha, followed by Bacillus thuringiensis 2.0 kg/ha (148.6 q/ha) and Neem oil 5% (143.11 q/ha). The economic analysis further indicated that B. bassiana 2.0 kg/ha was the most economical treatment, with the highest cost-benefit ratio of 1:3.10, followed by B. thuringiensis 2.0 kg/ha (1:3.05), Neem oil 5% (1:3.02), and Metarhizium anisopliae 2.0 kg/ha (1:2.93). In comparison, the control recorded a lower yield of 87 q/ha and a cost-benefit ratio of 1:1.90. Therefore, Beauveria bassiana 2.0 kg/ha can be considered the most effective and economical bio-pesticide among the treatments evaluated under the conditions of the present study.

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