We are fortunate to have a lot of insects at La Genestiere. We have elegant damselflies and dragonflies, huge butterflies and moths, crickets and grasshoppers galore, and of course noisy cicadas. We like and encourage most of them – by creating ‘bug hotels’ for example. However there is one insect we definitely do not encourage. It’s bactrocera oleae – the olive fruit fly. It is a serious pest in olive-growing regions, having an effect on the quality and quality of production. It does so through its habit of laying eggs in olives in summer when they are more than 8mm in diametre.

It is possible to control olive fruit fly using insecticides. However, we refuse to use pesticides and insecticides. Instead, we use two natural methods. The first is to discourage the flies from alighting on our trees in the first place. We do this by spraying each tree with a suspension of kaolin. This creates a dusty film on the leaves and olives. It appears that olive fruit flies can’t bear to get their legs dirty! We will probably spray two or three times through the summer.

Our second approach is to trap those flies that stubbornly won’t move on. We do this by creating traps out plastic bottles. We drill two 5.5mm holes in the neck of a 1.5 litre bottle. We half fill each bottle with a solution of diammonium phosphate (DAP) – a commonly used fertiliser. Then we hang a trap in each of my trees, in the shade so that the solution doesn’t evaporate too quickly. The flies are attracted by the scent of ammonia and enter the bottle through one of the holes. With a bit of luck, they are then unable to get out. We will have to top each bottle over the course of the summer.

We have had a mild winter this year, which usually results in more flies overwintering. Against that, the weather in July has been very hot and dry: conditions not to the liking of the fruit fly

I can’t make my mind up whether I will be pleased or disappointed if and when I should find olive fruit flies floating in my traps!

A cricket at La Genestiere

One of the good guys we encourage.

Spraying with a suspension of kaolin.

This creates a mineral film on the leaves and fruit.

The mineral film after spraying.

The olive fruit fly hates to get its feet dirty!

Our home made fruit fly traps.

The smell of ammonia encourages the fly to enter the bottle through one of the holes. It is a one-way trip.