Common tansy

The action of tansy (Tanacetum vulgare) as a crop protection agent is based on its high content of specific secondary metabolites, particularly essential oils containing thujone, camphor, and borneol. These compounds possess distinct repellent and insecticidal effects, acting on the nervous system of insects.

In the chemical class of bio-preparations based on plant raw materials, tansy is classified as a contact insecticide of natural origin. It disrupts the metabolic processes of phytophages, causing their disorientation, reduced feeding, and subsequent death upon prolonged exposure.

The mechanism of action also includes fungistatic properties, where plant components inhibit the growth of pathogenic fungi mycelium on leaf surfaces. Tansy phytoncides create a protective barrier that prevents plant colonization by pests and infection by pathogen spores.

Tansy-based preparations primarily function through phytochemical impact, lacking the systemic effect characteristic of synthetic pesticides. This defines their role as an auxiliary tool in integrated pest management programs.

The efficacy of active ingredients depends on the concentration of terpenoids, which varies according to the plant growth stage and harvesting conditions. Standardizing extracts is a key factor in achieving predictable protective results.

The main spectrum of application includes controlling a wide range of pests on fruit, berry, and vegetable crops. Preparations are effective against aphids, psyllids, weevils, and early-instar leaf-eating caterpillars.

Tansy-based extracts are also used to suppress populations of herbivorous mites. Due to their specific odor, they act as effective repellents, deterring insect pests from young seedlings of cultivated plants.

In disease control, tansy demonstrates activity against various phytopathogens causing leaf spots and powdery mildew during the initial stages of infection development. It limits spore dispersal and primary infection sites on vegetative parts of plants.

• Aphids and psyllids
• Weevils
• Herbivorous mites
• Early-instar caterpillars
• Powdery mildew pathogens

Tansy is successfully used as a preventive measure in greenhouse management, reducing pest density in indoor environments with regular applications. This allows for a reduction in the use of harsh chemical pesticides during the fruiting period.

When using tansy extracts as an insecticide, it is recommended to maintain an interval of 7–10 days between applications. A high concentration of active ingredients in the working solution is necessary to achieve a visible protective effect during periods of high pest activity.

In agronomic practice, infusions and decoctions from fresh or dried plant material are commonly used. The optimal application period is in the evening, preventing the rapid degradation of terpenoids under intense ultraviolet radiation.

The application rate of the preparation should be adjusted based on pest population density and the extent of leaf surface development. Uniform wetting of the entire above-ground part of the plant is a critical condition for comprehensive protection.

It is important to consider the crop's growth stage, as rapid leaf growth early in the season requires repeated applications to protect young tissues. During flowering, applications should be performed with caution to avoid disturbing pollinating insects.

To improve adhesion and prolong the effect, biologically neutral surfactants are added to the working solution. This allows for a reduction in the total amount of preparation used per hectare without losing the biological efficacy of the treatment.

A major limitation is the instability of active ingredients in the external environment. Under sunlight and high temperatures, tansy components oxidize quickly, requiring frequent repeat applications compared to synthetic agents.

Tansy has moderate toxicity to warm-blooded animals if ingested, so personal protective measures must be followed when handling concentrates. Avoid contact of concentrated solutions with mucous membranes.

Exceeding recommended dosages is not advised, as an excessive amount of essential oils can cause phytotoxic effects, manifesting as leaf burns, especially when applied during hot weather.

The efficacy of the preparation is significantly reduced by rainfall shortly after spraying. In a rainy season, the protective interval between applications must be shortened to maintain the necessary concentration of active ingredients on the plants.

Storing tansy-based preparations requires airtight containers in a cool, dark place. During storage, chemical composition may change due to the evaporation of volatile compounds, leading to a gradual loss of insecticidal properties.