Tar acids

Tar acids are a complex mixture of organic compounds obtained through the thermal decomposition of wood (primarily birch). Chemically, this is a mixture of phenols, guaiacol, cresols, and other organic acids.

The primary mechanism of action for this substance is a pronounced repellent effect. Due to its sharp, persistent odor and specific chemical composition, tar acid-based products mask the natural scents of plants that attract insects and rodents.

In addition to repellent properties, tar acids exhibit antiseptic and fungistatic activity. They suppress the development of phytopathogenic fungi on the surface of tree bark, creating a barrier environment that hinders the colonization of disease agents.

The substance acts via contact without penetrating deep into plant tissues, making it safe regarding the absence of systemic toxic residues in the final harvest. The effect persists for a long period due to the slow evaporation of components.

Products based on this group are not classical poisons intended to exterminate pests. Their purpose is to create conditions under which the target object (the pest) leaves the area of exposure or loses interest in the food source.

The main purpose of this group is the protection of fruit and ornamental crops from a wide spectrum of pests. Products are effective against rodents, particularly voles, which damage the bark of young trees during the winter period.

Tar acids are used to control harmful insects such as onion and carrot flies, cabbage worms, and various types of aphids. The sharp tar odor disorients females during oviposition.

In horticulture, this group is used to deter deer, rabbits, and other wild animals capable of causing mechanical damage to young plantings and seedlings in nurseries.

Additionally, tar acids can be used for the disinfection of tree wounds caused by pruning, preventing the development of rot and secondary fungal infections.

The agents also demonstrate activity against various soil pests if used as part of specific soil applications or as seed treatments (depending on the formulation).

Application rates vary depending on the specific product formulation and the objective. When treating tree basins or trunks, solutions with a tar concentration of 5% to 10% are typically used.

For controlling vegetable flies, baits or row spraying are often applied, where the active substance concentration is selected to avoid chemical burns to the tender leaves of young plants.

Treatment timing is determined by the pest's biological cycle. Protecting bark from rodents is carried out in the autumn, before the onset of persistent cold weather, to create a stable deterrent barrier for the entire winter.

When used as an insecticidal repellent, treatments are performed prophylactically before the start of mass pest migration, repeating the procedure every 10–14 days depending on weather conditions and precipitation.

It is important to note that high humidity and heavy rain reduce efficacy, so repeat treatments or renewal of the protective coating is often required after precipitation events.

The main limitation is the specific odor, which can linger on plants for quite a long time; therefore, it is not recommended to apply these products immediately before harvesting (within 10–15 days).

When handling concentrated tar acids, it is necessary to use personal protective equipment for skin and respiratory protection, as the components can cause irritation to mucous membranes.

Direct contact of concentrated tar with young leaves and growth points must be avoided, as this may lead to phytotoxicity and foliage burns.

Products in this group should be stored in tightly closed containers in a cool place, away from fire sources and food products, considering their flammability and strong odor.

Before mass application on new crops, it is recommended to conduct a test on a small area to ensure no negative reaction from the specific plant variety occurs.