Citronella oil

Citronella oil belongs to the group of natural essential oils extracted primarily from plants of the genus Cymbopogon. As an active ingredient in plant protection products, it is classified as a biopesticide with contact insecticidal and repellent properties.

The mode of action is based on disrupting insect receptors and exerting a physical effect on their cuticle. Upon contact with the oil, dehydration of the pest's outer integument occurs, leading to a loss of water balance and rapid mortality.

The scent of citronella oil possesses a strong repellent effect for most flying insects. It effectively masks the chemical signals of plants that pests use to identify food sources and egg-laying sites.

The biochemical activity of the oil is attributed to its high content of monoterpenes, such as citronellal, geraniol, and limonene. These compounds exhibit low toxicity to warm-blooded organisms, making them suitable for environmentally friendly agricultural practices.

The compound degrades rapidly under the influence of sunlight and microorganisms, which prevents the accumulation of residues in produce and soil. This characteristic makes citronella oil suitable for application shortly before harvest.

This substance group is primarily used against a wide range of small insect pests. In particular, the oil effectively suppresses populations of aphids, whiteflies, thrips, and various species of spider mites on vegetable crops.

High efficacy has also been proven against mosquito larvae and other blood-sucking insects in areas with high humidity. Application is limited to contact action, so thorough coverage of the leaf surface during spraying is essential for success.

Application rates depend on the concentration of the active ingredient in the finished formulation and the type of target pest. Typically, aqueous emulsions with an active ingredient concentration ranging from 0.5% to 2% are used.

Timing of applications is tied to the phases of active flight or the hatching of pest larvae. Repeated applications every 5–7 days are recommended to eradicate new generations, as the oil has a short residual protective effect.

The primary limitation is phytotoxicity if the concentration is exceeded, especially under conditions of high temperature and intense solar radiation. Spraying during midday hours is not recommended to avoid burning the leaf blades.

Citronella oil is characterized by low stability in field conditions; therefore, effectiveness may decrease during high winds or precipitation. Storage in airtight containers away from heat sources and direct sunlight is required to maintain insecticidal properties.