Users often regard the uptake of certain plant protection active ingredients by plants as a constant property, and product brochures do little to challenge this assumption. However, it is important to recognise that the absorption of locally systemic (translaminar) and truly systemic active ingredients through the outer surface of leaves can vary considerably.

The degree of active ingredient penetration may be affected by the waxiness of the leaf. This is well known from the practice of postponing treatment with certain herbicides for several days after heavy rainfall in order to protect the crop until an adequate wax layer has developed again.

The wax layer, consisting of fatty acid esters and cutin, can reduce the achievable pesticidal effect of non-contact insecticides, acaricides and fungicides. This can be particularly disadvantageous when controlling pests that have a concealed lifestyle, inhabit parts of the plant that are difficult to reach with the spray solution, or live within plant tissues.

There are currently no fully systemic products among our acaricides; once applied to the plant, they act either by contact or through translaminar activity. Since spider mites most commonly begin to multiply on the more protected underside of leaves, delivering the spray solution to their habitat presents a significant challenge. Choosing an effective adjuvant is therefore especially important when applying acaricides. Based on practical experience to date, oil-containing efficacy enhancers have become widely used and can provide a considerable improvement in performance.

This is the first product in Hungary to have been specifically developed and authorised as an adjuvant for acaricides. Its use improves the absorption of the acaricide into the plant, thereby enhancing its overall pesticidal effect (Figure 1). This is particularly beneficial when the leaves of the treated plant have become somewhat thickened or waxy due to environmental conditions.

Growers already use various oil-containing substances to enhance efficacy. Although these can also be effective, Avola was developed specifically for this purpose. It contains several ingredients that facilitate absorption, the most notable of which is avocado oil. Its other components also contribute to improving the uptake of the active ingredient.

The efficacy-enhancing properties of Avola EC were also examined in a laboratory trial on thickened, waxy summer apple leaves. It was used as an adjuvant for Flumite 200, an ovicidal acaricide with translaminar activity.