Petroleum oils

Petroleum oils belong to the group of mineral oils and are products of oil refining that have been purified of harmful impurities. They act mainly through contact and do not have systemic properties within the plant.

The primary mechanism of action is the creation of a thin oil film on the surface of the treated object. This film covers the breathing holes (tracheae and spiracles) of insects and mites, leading to their death by suffocation.

Additionally, petroleum oils can dissolve the chitinous layer or waxy coating on the surface of pest eggs. This destroys the protective covers of the egg clutches, preventing the development of embryos inside.

Preparations based on petroleum oils act as a mechanical barrier, so their effectiveness depends directly on the quality and uniformity of covering the plant surface with the working solution.

An important aspect is the absence of habituation in pests to this type of impact. Since the oil kills through physical means, the development of resistance is virtually excluded, allowing them to be used for years.

This group of products is used as insecto-acaricides for controlling a wide range of pests in the dormant or vegetative phase. They are especially effective against overwintering stages of insects.

The main targets for application are scales and soft scales, which are reliably protected by their shells. The oil penetrates under the shell and ensures the death of the pest, which is inaccessible to contact poisons.

Oils are also successfully used to control aphids, mealybugs, psyllids, and various species of plant-feeding mites, including spider mites in various stages of development.

The preparations are often used for treating fruit crops against pest eggs laid in bark cracks and on branches. This allows for a significant reduction in the pest population even before spring bud burst.

• Scales and soft scales
• Plant-feeding mites
• Aphids and psyllids
• Mealybugs
• Overwintering pest eggs

The application rates for petroleum oils depend on the crop, phenological stage, and the specific type of pest. Typically, the concentration of the working solution varies from 1% to 3% for early spring treatments.

During the growing season, it is necessary to use lower concentrations (0.5–1%) to avoid phytotoxicity to green plant parts, especially at high ambient temperatures.

It is important to thoroughly wet all surfaces of the tree, including bark, branch bases, and the underside of leaves, as contact with oil only on part of the insect's body may not be enough to destroy it.

Temperature control is crucial: treatments should not be carried out at temperatures below +5°C (due to thickening of the product) or above +25°C, as there is a high risk of leaf burn and evaporation of the active ingredient.

Oil application is often combined with other insecticides to enhance the effect, but before mixing, it is necessary to check the preparations for compatibility to avoid causing chemical burns to the plant.

Petroleum oils can exhibit phytotoxicity if applied incorrectly. It is not recommended to treat plants during the flowering period or if the crop is in a weakened state, as the oil film may block gas exchange in the stomata.

It is forbidden to mix petroleum oils with sulfur-containing products or with captan. The interval between the application of these substances should be at least 3-4 weeks to avoid severe tissue burns.

Avoid using oils on crops sensitive to petroleum products, such as certain varieties of grapes, pears, or ornamental plants with pubescent leaves.

To minimize risks to beneficial insects, treatments should be carried out during the morning or evening hours, when the activity of bees and other entomophages is minimal.

Storage of the preparations requires adherence to temperature conditions, excluding overheating or freezing of the container, as a violation of the emulsion structure makes the product unsuitable for further use.