Effect of Nozzle Type and Discharge Rate on Spray Characteristics and Insecticidal Bioefficacy in Chickpea and Bottle Gourd Using a Battery-Operated Knapsack Sprayer
Thokchom Macedonia Devi *
Department of Farm Machinery and Power Engineering, College of Agricultural Engineering and Technology, Junagadh Agricultural University, Junagadh – 362001, Gujarat, India.
T. D. Mehta
Department of Farm Machinery and Power Engineering, College of Agricultural Engineering and Technology, Junagadh Agricultural University, Junagadh – 362001, Gujarat, India.
*Author to whom correspondence should be addressed.
Abstract
Background: Nozzle type and discharge rate can affect spray deposition and pest management when battery-operated knapsack sprayers are used in field crops.
Objective: To assess the effects of nozzle type and discharge rate on spray deposition characteristics and insecticidal bioefficacy in chickpea and bottle gourd using a battery-operated knapsack sprayer. A two-factor completely randomised design comprising four nozzle treatments, three discharge-rate settings and three replications was used.
Place of Study: SWCE Farm Research Station and Vegetable Farm Research Station, Junagadh Agricultural University, Junagadh, India, in 2025–26.
Methodology: Three nozzle types, namely hollow cone (N1), flat fan (N2) and solid cone (N3), were selected for performance evaluation using a battery-operated knapsack sprayer under laboratory and field conditions, while a control nozzle (N4) was included for comparison. Spray characteristics were evaluated using water-sensitive papers, and parameters such as droplet density, spray coverage, volume median diameter (VMD), number median diameter (NMD), droplet deposition and homogeneity factor (HF) were analysed using ImageJ software. Additionally, bioefficacy was evaluated in terms of pest numbers before spraying and at 3, 7 and 14 days after spraying.
Results: In chickpea, the hollow cone nozzle operated at a high discharge rate resulted in the lowest relative thrips population (26.23%). In bottle gourd, the hollow cone nozzle recorded the lowest relative populations of aphids (36.74%) and whiteflies (23.59%). Overall, the results demonstrated that nozzle type and discharge rate significantly influenced spray quality, canopy coverage, droplet distribution and pest control efficiency. Statistical analysis confirmed that all main effects and interactions were highly significant (p < 0.01), and the coefficient of variation remained low, indicating the precision and reliability of the findings.
Conclusions: The study concluded that the hollow cone nozzle performed best for chickpea and bottle gourd when operated at higher discharge rates. The findings indicate that crop-specific nozzle selection can significantly enhance pesticide application efficiency, improve pest management, reduce chemical wastage and minimise environmental contamination. Therefore, adopting appropriate nozzle–discharge-rate combinations can contribute to sustainable and precise crop protection practices.
Keywords: Chickpea, bottle gourd, bio efficacy, battery operated knapsack sprayer