Kaolin, biological treatment for olive trees and vines

Here's how we use kaolin powder to protect olive trees and vines from insects and excessive heat from summer sun rays

We at Podere Conca have been cultivating our 800 olive trees for years according to certified organic farming methods and are therefore currently collaborating with Olivicoltori Toscani Associati ,  Agea , and Terre dell'Etruria , to the campaign “Improving the environmental impact of oviculture” financed with the contribution of the European Union and Italy.

The campaign develops a program of defense against the olive fly through the use of kaolin.

The fly is in fact one of the most dangerous threats to the quality of olives and the oil produced.

What is kaolin?

Kaolin is a clay, a soft sedimentary rock, which is used in organic farming in the form of a powder to be mixed with water in different concentrations and then sprayed on plants through sprayers.

This creates a shiny white patina that, unlike synthetic products prohibited in organic farming, forms a physical barrier that acts as a repellent and as a protective mask that discourages the fly from piercing the surface of the olive and laying its eggs.

The olive fly

The olive fly is in fact particularly harmful because in addition to causing loss of pulp, it affects the ripening and the strength with which the olive is attached to the stalk and therefore can cause it to fall, making it unusable for the production of quality oil.

Furthermore, when the larva is mature, it will exit the olive and create a rather large hole through which infesting microorganisms can penetrate, causing biochemical changes to the fruit with consequences on the quality and acidity of the oil.

The treatments

In the experiment we are carrying out, two or three treatments are planned starting from June until September, depending on the seasonal trend.

Kaolin is not harmful to humans and will dissolve with the first autumn rains.

Our olives will also be carefully washed at the mill before cold pressing.

Certainly the costs of these treatments are higher than the traditional ones performed with synthetic products as they must be performed more frequently, but the fact that our oil is certified organic is certainly an added value that will become essential in the years to come.

To obtain the maximum quality, with minimum acidity, it is therefore essential for us that the olives, which we pick by hand, are completely intact.

The result is a Tuscan organic extra virgin olive oil with an acidity lower than 0.8%, green in colour with golden reflections, with a fruity nature and non-invasive notes of artichoke.

Control of thermal and water stress

In these increasingly hot and rainless summers, kaolin has also become a great help in protecting plants from thermal and water stress.

The bright white of its powders reflects part of the sun's rays, helping to lower the temperature on the leaves, limiting their transpiration and limiting damage from thermal stress.

In this case we also use kaolin on our vines.

by Cristina Bernezzo and Linda Franceschi