Browsing by Author "Sajay,S"

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    Horticultural mineral oil for pest management in Brinjal and Chilli
    (Department of Agricultural Entomology, College of Agriculture, Padannakkad, 2026-01-31) Sajay,S; Sreekumar, K M
    The research programme entitled ‘Horticultural mineral oil for pest management in brinjal and chilli’ was aimed at elucidate the mode of action, phytotoxicity, safety to natural enemies, compatibility and pest management efficacy of horticultural mineral oil in brinjal and chilli. Safety evaluation of horticultural mineral oil was carried out in the Department of Agricultural Entomology, College of Agriculture, Padannakkad, during 2022-23 to evaluate phytotoxicity, toxicity to natural enemies and compatibility with biocontrol agents. Eleven concentrations of HMO (HMO at 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5% and 8%) and a control were applied on one month old seedlings of brinjal and chilli as part of phytotoxicity evaluation. For experimenting on natural enemies and biocontrol agents, six concentrations of HMO (HMO at 2%, 2.5%, 3%, 3.5%, 4% and 4.5%) and a control were evaluated. All the safety evaluation experiments were designed under CRD with three replications. Results showed that HMO up to 6.5% did not show any phytotoxic symptoms in both brinjal and chilli. But HMO at 7%, 7.5% and 8% resulted in phytotoxicity symptoms like necrotic patches, with the severity of these symptoms showing an increasing trend as the concentration increased. HMO at 2% is safest for Trichogramma chilonis, Bracon brevicornis, Cheilomenes sexmaculata and Chrysoperla sp. followed by 2.5% and 3%. HMO is not compatible with biocontrol agents such as Beauveria bassiana, Metarhizium anisopliae, Lecanicillium lecanii and Trichoderma asperellum. Laboratory evaluation of horticultural mineral oil against selected pests of brinjal and chilli was carried out in the Department of Agricultural Entomology, College of Agriculture, Padannakkad, during 2022-23 to evaluate the toxicity against grubs of epilachna beetle Henosepilachna vigintioctopunctata and caterpillar of shoot and fruit borer Leucinodes orbonalis. A net house experiment was conducted to find the repellency of chilli whitefly, Aleurothrixus trachoides. The test organisms were exposed to seven treatments including T1: HMO at 2%; T2: HMO at 2.5%; T3: HMO at 3%; T4: HMO at 3.5%; T5: HMO at 4%, T6: HMO at 4.5% and T7: control designed under CRD with three replications. From the results, HMO at 4.5% caused the highest significant mortality of Leucinodes orbonalis which was on par with 4% followed by 3.5%, and 3%. HMO at 4.5% caused the highest significant mortality of Henosepilachna vigintioctopunctata, which is on par with 4% followed by 3.5%, and 3%. HMO at 4.5% resulted in the highest significant repellency against Aleurothrixus trachoides, which was on par with 4% followed by 3.5%, and 3%. HMO at 3% was selected as the best concentration based on the results of safety evaluation experiments and laboratory evaluation of selected pests. Field study was carried out using RBD with eight treatments and three replications on brinjal and chilli from November 2023 to April 2024 at the Instructional farm of College of Agriculture, Padannakkad. Treatments applied in brinjal were: T1: HMO at 3 %; T2: HMO at 3 % + azadirachtin formulation at 1 % 1ml/L; T3: azadirachtin formulation at 1 % 2ml/L; T4: HMO at 3 % + thiamethoxam 25WG 0.1g/L, T5: thiamethoxam 25WG 0.2g/L, T6: HMO at 3 % + chlorantraniliprole 18.5SC 0.15ml/L, T7: chlorantraniliprole 18.5SC 0.3ml/L and T8: untreated control and treatments applied in chilli were T1: HMO at 3 %, T2: HMO at 3 % + azadirachtin formulation at 1 % 1ml/L, T3: azadirachtin formulation at 1% 2ml/L, T4: HMO at 3 % + thiamethoxam 25WG 0.2g/L, T5: thiamethoxam 25WG 0.4g/L, T6: HMO at 3 % + fenpyroximate 5EC 0.3ml/L, T7: fenpyroximate 5EC 0.6ml/L and T8: untreated control. Observations on pest population were made a day prior to spraying and post treatment population at 1,3,5,7 and 14 DAT while damage symptoms were observed at 7 and 14 DAT. Results indicated that, HMO at 3% in combination with half the recommended dose of chemical pesticides (azadirachtin formulation 1 % 1ml/L, thiamethoxam 25WG 0.1g/L, and chlorantraniliprole 18.5SC 0.15ml/L) yielded the same significant results when compared with the full recommended dose (azadirachtin formulation 1% 2ml/L, thiamethoxam 25WG 0.2g/L and chlorantraniliprole 18.5SC 0.3ml/L) against epilachna beetle Henosepilachna vigintioctopunctata in brinjal. HMO at 3% in combination with chlorantraniliprole 18.5SC 0.15ml/L (half the recommended dose) and chlorantraniliprole 18.5SC 0.3ml/L (full recommended dose) achieved the highest reduction in the damaged shoots and fruits caused by the attack of shoot and fruit borer Leucinodes orbonalis in brinjal. HMO at 3 % in combination with thiamethoxam 25WG 0.1g/L (half the recommended dose) was superior among all other treatments against leaf hopper Amrasca biguttula biguttula in brinjal, which was on par with treatment thiamethoxam 25WG 0.2g/L (full recommended dose). HMO at 3% in combination with chlorantraniliprole 18.5SC 0.15ml/L recorded the highest marketable yield of brinjal, which was followed by chlorantraniliprole 18.5SC 0.3ml/L and HMO 3% in combination with azadirachtin formulation 1% 1ml/L. HMO at 3% in combination with fenpyroximate 5EC 0.3ml/L (half the recommended dose) achieved the best result, which was on par with fenpyroximate 5EC 0.6ml/L (full recommended dose) against chilli mite Polyphagotarsonemus latus in chilli. HMO 3% in combination with fenpyroximate 5EC 0.3ml/L and thiamethoxam 25WG 0.2g/L (half the recommended dose) resulted in highest success rate in controllling the thrips Thrips parvispinus population in chilli which was on par with fenpyroximate 5EC 0.6ml/L and thiamethoxam 25WG 0.4g/L (full recommended dose). HMO at 3 % in combination with thiamethoxam 25WG 0.2g/L (half the recommended dose) combination gave the best results among all other treatments against whitefly Aleurodicus disperses in chilli, which was on par with treatment thiamethoxam 25WG 0.4g/L (full recommended dose). HMO at 3% in combination with fenpyroximate 5EC 0.3ml/L recorded the highest marketable yield of chilli, which was followed by fenpyroximate 5EC 0.6ml/L. The scanning electron microscope (SEM) study conducted to find out the morphological changes in Myzus persicae and Spodoptera litura treated with HMO 3% indicated that the treatment changed the mouthpart morphology of Myzus persicae. SEM images also revealed that HMO 3% blocked the spiracles and damaged the trichomes, and produced significant changes in the structure of the cuticle of Spodoptera litura. A comparative study of the droplet spreading area of HMO, insecticides, and their combinations was designed under CRD with nine treatments and three replications. Treatments applied were: T1: HMO at 3 %; T2: HMO at 3 % + azadirachtin formulation at 1 % 1ml/L; T3: azadirachtin formulation at 1 % 2ml/L; T4: HMO at 3 % + thiamethoxam 25WG 0.1g/L, T5: thiamethoxam 25WG 0.2g/L, T6: HMO at 3 % + chlorantraniliprole 18.5SC 0.15ml/L, T7: chlorantraniliprole 18.5SC 0.3ml/L, T8: HMO at 3 % + fenpyroximate 5EC 0.3ml/L and T9: fenpyroximate 5EC 0.6ml/L. Results showed that, the droplets of the combinations having HMO at 3% and HMO at 3% alone spread more compared to chemical formulations which used alone. Since oil plus emulsifier in the HMO reduces surface tension and creates more stable dispersed droplets, when sprayed on leaves or other plant surfaces, the chemical combination with HMO can spread more effectively than with the chemical applied alone.