The effect of foliar application of vermiwash enriched with Poshan on the yield and quality of Mulberry (Morus sp.) and Silkworm (Bombyx mori)

Introduction

Sericulture, or the cultivation of silkworms for silk manufacture, is a biologically specialized and economically significant agricultural enterprise. Bombyx mori, a domesticated silkworm species that feeds solely on Morus spp. (mulberry) leaves, is fundamental to this activity. Mulberry, a deep-rooted, perennial plant, is extremely responsive to nitrogen inputs due to its rapid growth and dense foliage (Altman & Farrell, 2022) [3] . Its productivity directly influences the health and silk-producing ability of silkworms. As a result, the physiological quality of mulberry leaves specifically, their protein, sugar, and moisture content is crucial in The consistent positive correlation between cocoon production and leaf quality highlights the necessity of prompt and focused nutrient management in mulberry production (D et al., 2024) [6] . Another important argument for using foliar feeding is its economic and operational efficiency. In comparison to soil fertilization, foliar sprays require fewer inputs and provide faster visible results. Furthermore, their compatibility with other agrochemicals (such as insecticides and fungicides) enables farmers to combine treatments, lowering labor costs and operating time. The ability to modify foliar compositions based on the plant's developmental stage and specific deficiency symptoms identified makes it a precise, farmer-friendly approach. (Niu et al., 2021) [15] . Despite the effectiveness of chemical foliar fertilizers, rising environmental and health concerns have led to a global trend toward more sustainable and environmentally friendly agriculture practices. The overuse of synthetic fertilizers and pesticides has resulted in widespread problems such as soil acidification, groundwater contamination, disturbance of soil microbiology, and pesticide resistance (Baweja et al., 2020) [4] . These long-term repercussions necessitate an immediate shift to more balanced farming practices that promote both production and environmental health. As a result, organic and bio-based foliar treatments are being investigated not only as alternatives, but also as strategic enhancers of crop performance in integrated nutrition management systems. Poshan is one of the commercially available foliar formulations that has drawn a lot of interest because of its tailored formulation and effectiveness. Poshan is an expertly created multi-nutrient solution made especially for mulberries. Applying it topically during the vegetative and leaf maturation phases of mulberry growth is advised since it includes all of the necessary macro-and micronutrients in accessible forms. One application of Poshan is said to improve chlorophyll content, boost plant metabolism, address obvious nutrient deficiencies, and promote consistent and healthy leaf development. Poshan can greatly enhance cocoon weight, shell weight, and silk quality in B. mori and produce up to 20% more mulberry leaves under ideal circumstances. This formulation not only supports healthy plant growth but also reduces the need for frequent chemical fertilizer applications, making it a cost-effective option for farmers practicing intensive sericulture (Alipanah et al., 2020) [2] . The excessive and prolonged use of chemical fertilizers and pesticides has caused health and environmental issues, even while synthetic foliar sprays like Poshan provide quick and noticeable gains in crop performance. These have an adverse effect on long-term soil production and ecological stability and include pesticide residue accumulation, microbial imbalance, water pollution, and soil acidification. As a result, organic and sustainable farming inputs that increase plant yield without sacrificing environmental integrity are gaining popularity worldwide (Aktar et al., 2009) [1] . Among these inputs, vermicompost and vermiwash, which are byproducts of vermiculture, are becoming more and more acknowledged for their capacity to support integrated pest and nutrient management systems, encourage plant development, and restore soil health. Vermiwash is a liquid biofertilizer that is created by letting water run through a column filled with earthworms, typically Eisenia fetida, and organic debris. Mucus secretions, earthworm excretory products, enzymes (such as urease, phosphatase, and amylase), plant growth hormones (such as auxins and cytokinins), vitamins, and a range of beneficial bacteria are all included in the nutrient-rich extract that is the end result of this process. The resulting liquid is typically clear, slightly alkaline, and pale yellow. When used as a foliar spray, vermiwash has been shown to increase plant growth, photosynthetic activity, nutrient uptake, and resistance to pests and diseases. Because it acts as a natural biopesticide and growth stimulant, it is suitable for organic and eco-friendly farming practices (Gudeta et al., 2021) [10] . Vermiwash has several advantages, but one drawback is that it contains fewer macronutrients than synthetic preparations. Because of this, it is less successful when used alone, especially in crops with high demand, like mulberries, where a steady supply of nutrients is essential for the best possible development of leaves and silk. Recent research has investigated enriching vermiwash with extra nutrients or bio-enhancers to produce fortified foliar compositions in order to overcome this restriction. In order to satisfy the needs of high-yielding cultivars, these enriched versions seek to combine the inherent advantages of vermiwash, such as microbial stimulation and hormone activity, with improved nutritional content ((Nahar et al., 2024) [14] (Che Sulaiman & Mohamad, 2020) [5] . On considering this, the current study aims to study the effect of foliar application of vermiwash supplemented with POSHAN on the growth of mulberry and the biochemical content of its leaves. And assess the nutritive quality of mulberry leaf sprayed with vermiwash supplemented with POSHAN through silkworm rearing.

Materials and Methods

Investigations on the effect of foliar spray of Poshan supplemented vermi-wash on yield, chemical content and cocoon production potential of mulberry (Morus sp.) leaves were carried out in the Department of Studies in Sericultural Science. University of Mysore, Manasagangotri, Mysuru, during March-May. Vermiwash was procured from the Biowaste Management Project of the Department. In the Department's experimental garden, a high-yielding mulberry cultivar called Victory-1 (V1) was kept under drip irrigation for the foliar spray experiment. 128 mulberry plants were chosen, and they were split up into four treatment groups with four replications each. In order to maintain uniformity and reduce environmental variability, eight plants were used in each replication. A randomized block design was used in the experimental setup to minimize experimental error and enable precise treatment comparisons.

Treatment

Vermiwash was combined with Poshan at a 3:1 ratio and used as the primary therapy. It was tested against vermiwash alone, Poshan alone, and a control (no spray). The four therapies used were:-T1: Control(No-Spray) T2: Vermiwash+Poshan(3:1). T3: Vermiwash alone. T4: Poshan-alone.

Each treatment was applied to four randomized replications with a hand sprayer in the cool morning hours. The first spray was applied 40 days after pruning, followed by a second spray 10 days later. Standard cultural procedures, such as irrigation and manure treatment, were followed similarly throughout all plots.

Silkworm rearing

To evaluate the nutritional quality of mulberry leaves under different treatments, a bioassay through silkworm rearing was conducted in the departmental rearing house. Disease-Free Layings (DFLs) of the hybrid silkworm strain PM × CSR2 were obtained from the National Silkworm Seed Organization (NSSO), Mysuru. Prior to rearing, a 2% bleaching powder solution was used to completely clean and disinfect the rearing room and its equipment. Astra/Sanitech was then used for a second disinfection. Using leaves from each treatment group independently, rearing was done from the fourth to the fifth instar. Four replications, each containing 100 larvae, were kept in different trays for every treatment. Throughout the trial, standard silkworm raising procedures were adhered to.

Observations Recorded

After 10 days of the final spray, mulberry growth and leaf yield were observed using the methods listed below:  Raw silk percentage: Raw silk percentage was estimated in each treatment, replication-wise, using the following formula:

 Renditta: Renditta was estimated in each treatment, using the following formula:

 Denier: Denier was worked out in each treatment, using the formula below.

Each parameter was calculated replication-wise for all treatments, and data were statistically analyzed to determine treatment effects.

Estimation of Biochemical parameters  Carbohydrate content:

The carbohydrate content in mulberry leaves was determined using the phenolsulfuric acid method from (DuBois et al., 1956) [8] . The leaves collected from the seventh position of the branch were shade dried, ground and extracted in 80% ethanol. A 0.1 mL aliquot of the extract was diluted with 0.9 mL distilled water and added to 1 mL of 5% phenol and then added to 5 mL of concentrated sulfuric acid. The extract was left for 20 minutes and absorbance was assessed at 490 nm using a spectrophotometer. Carbohydrate content was reported in mg/g dry weight with glucose as a standard.  Protein content: The protein content was determined using the Lowry's method (Lowry et al., 1951) [13] , with Bovine Serum Albumin (BSA) as the standard. The test was performed using shade-dried and powdered mulberry leaves (third or fourth position). One ml of sample was added to 5 ml of protein reagent and incubated for 10 minutes at room temperature, followed by 0.5 ml of Folin-Ciocalteu reagent. After incubation for 30 minutes, absorbance was measured at 660 nm.

The protein content was presented as mg/g dry weight.  Chlorophyll content: Chlorophyll content was determined using the method of (Hiscox & Israelstam, 1979) [11] utilizing absorbance (A) measurements at 645 and 663 nm. It used fresh leaf samples. The chlorophyll concentrations were also tentatively calculated using formula given below. The results were converted to mg/g fresh weight. The calculations used the following formulas:

The chlorophyll 'a', 'b', and total chlorophyll were computed using the following formulae. and the significance levels of treatments were calculated using the SPSS statistical software tool.

Results and Discussions

Mulberry plants in all four treatments responded favourably to foliar application of vermiwash enhanced with Poshan.

Figures 3456show the significant variations in growth parameters that were noted between treatments. Under each treatment, important growth metrics were noted, such as the number of branches per plant, branch length, and leaves per plant. 1 and indicated in the graph(Figure 1). The most effective growth response was indicated by T2 (Vermiwash + Poshan), which had the most branches, branch length, and leaf count of any treatment. While T1 (Control) consistently had the lowest values, treatments T3 (Vermiwash) and T4 (Poshan) demonstrated moderate improvements. Significant differences in branch length (p<0.01) and branch and leaf number (p<0.05) were found by statistical analysis. These results suggest that vermiwash and Poshan applied together have a synergistic effect on the growth of mulberry plants.

Cocoon quality parameters

The cocoon quality metrics for each treatment are displayed in Table 3 and Figure 3-6. T3 (Vermiwash) and T4 had longer filament lengths, but T4 (Poshan) had the highest raw silk weight (0.274 g) and denier (2.592). T2 (Vermiwash + Poshan) showed the lowest renditta, suggesting superior silk recovery. The fact that none of the differences were statistically significant, however, suggests that the foliar treatments had no appreciable impact on the characteristics of cocoon quality.

Data on carbohydrate and protein content

The impact of different treatments on the protein and carbohydrate contents of mulberry leaves is shown in Figure 3. The highest protein (84.93 mg/g) and carbohydrate (123.50 mg/g) contents among the treatments were found in T2 (Vermiwash + Poshan), indicating a notable improvement in the biochemical composition of the leaves. Additionally, T4 (Poshan) showed a notable improvement over the control. For both parameters, T1 (Control) displayed the lowest values. Significant differences were identified using Statistical analysis (p<0.01) in protein and glucose content between treatments, demonstrating the effectiveness of foliar supplementation, especially the combination of Poshan and vermiwash.

Chlorophyll content

The effects of foliar treatments on the amount of chlorophyll a, chlorophyll b, and total chlorophyll in mulberry leaves are displayed in Table 5 and Figure 9-11. The highest concentrations of all chlorophyll components were produced by the T2 (Vermiwash + Poshan) treatment; in particular, total chlorophyll (4.856 mg/g) and chlorophyll a (0.027 mg/g) were significantly greater than those of the other treatments. In contrast to the control (T1), which had the lowest values, T3 (Vermiwash) and T4 (Poshan) both had higher chlorophyll contents. Statistical analysis showed significant differences (p<0.01) in all measurements of chlorophyll, suggesting that the treatments-particularly the combination of Poshan and vermiwash-effectively raised the levels of photosynthetic pigment.

Result and Conclusion

The study looked at how vermiwash mixed with Poshan in a 3:1 ratio affected mulberry (V₁ variety) and silkworm (Kolar Gold hybrid) performance when used as a foliar spray. The treatment was compared to using vermiwash alone, Poshan alone, and a control that received no spray.

The results indicated that the combination of vermiwash and Poshan significantly boosted mulberry growth metrics, including branch number, branch length, and leaf count. Chemo-assay results showed much higher levels of carbohydrates, proteins, and chlorophyll in the leaves treated with the mixture. In the experiment, the combined treatment resulted in significantly greater larval and cocoon weights. However, pupal weight, shell weight, filament length, raw silk weight, renditta, and denier did not show significant differences between treatments. Overall, vermiwash, along with Poshan, proved to be the most effective method for improving both mulberry leaf quality and silkworm productivity. It offers a cost-effective and environmentally friendly alternative to separate foliar sprays, making it a promising addition for better sericulture practices.

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