Evaluation of indigenous botanical treatments for enhancing storability of sorghum (Sorghum bicolor) against storage pests

Introduction

Sorghum (Sorghum bicolor L. Moench) is an important cereal crop widely cultivated in tropical and subtropical regions of the world. It serves as a staple food for millions of people and also plays a significant role in livestock feeding and industrial uses. Sorghum is particularly important in semi-arid regions because of its ability to withstand drought and adverse climatic conditions (Hossain et al., 2022; Mwamahonje et al., 2024; Srivastava et al., 2025) [5,13,23] . In India, sorghum contributes significantly to food security and the livelihood of farmers in dryland agricultural systems (Kanthaswamy et al., 2025; Ronanki et al., 2022; Sahara et al., 2023) [6,19,20] . However, a substantial quantity of stored sorghum grains is lost due to insect pests and poor storage conditions. Storage pests such as rice weevil (Sitophilus oryzae), lesser grain borer (Rhyzopertha dominica), and red flour beetle (Tribolium castaneum) are responsible for considerable losses in stored grains (Desta & Yeshitila, 2024; Kłyś et al., 2017) [2,10] . Post-harvest losses of grains in developing countries are estimated to range between 10-30 per cent due to insect infestation and other storage problems (FAO, 2011). Chemical pesticides and fumigants are widely used to control storage pests; however, excessive use of these chemicals has resulted in several problems including pest resistance, environmental pollution and health hazards to humans and animals (Ahmad et al., 2024; Kashyap et al., 2024; Shekhar et al., 2024) [1,7,21] . In recent years, there has been increasing interest in ecofriendly pest management strategies using botanical products. Indigenous knowledge systems developed by farmers over generations provide effective and sustainable solutions for grain storage. Traditional storage practices involve the use of plant materials such as neem leaves, sweet flag rhizomes, chilli powder, and wood ash to protect stored grains from insect pests (Ahmad et al., 2024; Singh et al., 2021) [1,22] . Botanical products contain biologically active compounds which exhibit insecticidal, repellent, and antifeedant properties against storage pests (Ngegba et al., 2022; Pavela et al., 2025a) [14,15] . Neem-based products contain azadirachtin, which interferes with insect growth and reproduction (Kuhar et al., 2022; Mordue, 2004) [11,12] . Sweet flag (Acorus calamus) rhizome powder has also been reported to be effective in controlling rice weevil infestation in stored grains (Khanal et al., 2021) [9] . Although several indigenous plant products are traditionally used by farmers for protecting stored grains, scientific evaluation of their effectiveness in sorghum storage is limited. Therefore, the present investigation was undertaken to evaluate the effect of different indigenous natural and plant products on the storability of sorghum grains. The objective of this study was to evaluate the effectiveness of different indigenous natural and plant products in improving the storability of sorghum grains. The study aimed to assess their influence on seed damage, egg laying, and adult insect population during storage. It also focused on identifying eco-friendly and economical botanical treatments for protecting sorghum grains from storage pests. Previous studies have mainly focused on chemical methods for controlling storage pests in grains. However, there is limited scientific validation of indigenous natural and plant products used by farmers for sorghum storage. Many traditional practices remain undocumented and underresearched. Therefore, this study attempts to fill the gap by evaluating the effectiveness of indigenous plant-based treatments for safe sorghum grain storage.

Materials and Methods

Experimental Location

The experiment was conducted in the laboratory of the Agricultural Laboratory Complex, School of Agriculture and Animal Sciences, Gandhigram Rural Institute, Tamil Nadu.

Experimental Design

The experiment was laid out in a Completely Randomized Design (CRD) with three replications. Combinational treatments (T5-T11) integrate two or more of these materials to assess their synergistic effects in enhancing protection. T0 serves as the control without any treatment. These treatments are designed to study ecofriendly, low-cost methods for protecting stored materials against pests and spoilage.

Treatments

Preparation of Botanical Materials

Plant materials were collected, shade-dried and ground into fine powder. The required quantities of each botanical were mixed thoroughly with sorghum grains before storage.

Storage Procedure

Treated grains were stored in airtight containers under laboratory conditions for six months. Observations were recorded at intervals of 20, 40 and 60 days. The Sorghum variety CSH -14 was used in the study for both years.

Observations Recorded

The following parameters were recorded:  Seed damage percentage  Number of eggs laid  Number of alive adults

Statistical Analysis

Data obtained from the experiment were analyzed using Analysis of Variance (ANOVA) and treatment means were compared using appropriate statistical tests.

Results and Discussion

Effect on Seed Damage

The results revealed significant differences among the treatments in reducing seed damage during the storage period. Among the treatments, T₁₁ (T₁ + T₂ + T₃ + T₄) recorded the lowest seed damage at all observation intervals during both years of study Table . 2. The seed damage recorded in T₁₁ was 17.66, 14.33, and 11.66 per cent on the 20th, 40th, and 60th day, respectively, during the first year, whereas in the second year the values were 0.60, 3.00 and 0.00 per cent. Among the individual treatments, T₂ (coating with gingelly oil) showed comparatively better performance in reducing seed damage compared with other treatments. The untreated control (T₀) recorded the highest seed damage throughout the storage period.

The reduction in seed damage may be attributed to the repellent and insecticidal properties of botanical materials and oils, which interfere with feeding and reproduction of storage pests. Similar findings were reported by (Rajesh et al., 2022) [18] , who observed reduced insect infestation in seeds treated with botanical products.

Effect on Number of Eggs Laid

The number of eggs laid by storage pests was significantly influenced by different treatments. Among the treatments, T₁₁ (combination of red earth slurry, gingelly oil, neem leaf paste and dried chilli pods) recorded the lowest number of eggs laid during the storage period. The number of eggs laid in T₁₁ was 123.33, 109.00 and 99.66 on the 20th, 40th and 60th day respectively during the first year. In the second year, the values were 8.00, 12.30 and 14.60, which were considerably lower than the untreated control Table . 3. Among the individual treatments, T₂ (gingelly oil coating) also showed better effectiveness in reducing egg laying. The untreated control recorded the maximum number of eggs laid during the storage period. The reduction in oviposition might be due to the repellent and antifeedant properties of botanical products, which deter insects from laying eggs on treated grains. Similar results were reported by (Pavela et al., 2025b; Rajashekar et al., 2025) [16,17] . [3,8] .

Conclusion

The present study demonstrated that indigenous natural and plant products play an important role in improving the storability of sorghum grains. Among the different treatments, the combined treatment T₁₁ (red earth slurry + gingelly oil + neem leaf paste + dried chilli pods) was found to be the most effective in reducing seed damage, egg laying, and adult insect population during the storage period.

The results indicate that traditional botanical materials possess repellent and insecticidal properties that help in protecting stored grains. Therefore, the use of such indigenous practices can be promoted as eco-friendly, economical, and sustainable alternatives to chemical pesticides for safe grain storage and reduction of postharvest losses.

Acknowledgement

International Journal of Agriculture and Nutrition https://www.agriculturejournal.net

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