Valorization of clove (

Area of Science:

• Agricultural Science
• Entomology
• Natural Product Chemistry

Background:

• Clove (Syzygium aromaticum) by-products like stems and leaves are often underutilized.
• Post-harvest rice loss due to pests like rice weevils necessitates sustainable management strategies.
• Synthetic insecticides pose environmental risks and contribute to pest resistance.

Purpose of the Study:

• To evaluate the potential of clove stem and leaf essential oils as natural grain protectants against rice weevils.
• To analyze the chemical composition of these essential oils.
• To determine their repellent and insecticidal efficacy.

Main Methods:

• Essential oils were extracted from clove stems and leaves.
• Chemical composition was analyzed using gas chromatography-mass spectrometry (GC-MS).
• Contact repellent activity and fumigation mortality assays were conducted, calculating mortality percentage and LD50 values.

Main Results:

• Clove stem essential oil yielded higher (5.52%) than leaf essential oil (3.92%).
• Stem essential oil exhibited maximum repellency (100%) and mortality (96.67%) at 100 µL dose.
• The lowest LD50 (28.06 µL/L) was observed for stem essential oil, indicating higher toxicity. Major components identified include Eugenol and β-caryophyllene.

Conclusions:

• Clove by-products can be successfully valorized as effective grain protectants.
• Clove stem essential oil is a promising, eco-friendly alternative for managing rice weevils.
• This approach reduces reliance on synthetic insecticides and minimizes post-harvest losses.