Monitoring the olive fruit fly

As every year, the approach of summer marks the start of our monitoring of the olive fruit fly, Bactrocera oleae.

The olive fruit fly is one of the most damaging and dangerous pests of olive trees. It can cause fruit to drop prematurely and affect the quality of the olives, increasing the acidity of the oil.

Population growth generally stops during winter; the flies begin flying at temperatures above 14–18 °C. High summer temperatures also affect the survival of adults, above 39–40 °C, and larvae, above 33–35 °C. Temperatures above 30 °C also reduce female fertility. You can find more information about the olive fruit fly on the dedicated page of our website.

From mid-June, when the newly set olives begin to grow, we installed pheromone traps to monitor the olive fruit fly.

As part of integrated pest management, pheromone traps help us track population changes, adult flight activity and numbers.

Installing a trap to monitor the olive fruit fly

A BacTrap olive fruit fly monitoring trap

According to the technical sheet for BacTrap traps, distributed in Italy by Biogard, this is a yellow, corrugated-plastic delta trap with a holder for the pheromone dispenser. Its inner surface is coated with glue to capture adult flies. The trap combines the action of the pheromone, which attracts males, with the yellow colour, which mainly attracts females.

We check the traps twice a week. Monitoring adult flies helps us time the first preventive treatment with repellent or egg-laying deterrent products; its success depends on acting promptly.

When the proportion of infested olives reaches the threshold of 5–10%, appropriate chemical treatments become necessary.