Preliminary study on the combined effect of mating disruption and inundative releases of Trichogramma evanescens (West.) against the olive moth, Prays oleae (Bern.).

Three comparable olive groves (3.1 ha, each) of the same olive varieties (Toffahi and Shamy) were chosen in 2002-2003 olive season to study the combined effects of mating disruption and releases of an egg-parasitoid on the olive moth, Prays oleae . Field releases of 900000 wasps/ha/release were applied on olive trees against the anthophagous, carpophagous and phyllophagous generations of the olive moth on plots of the first and second olive groves. In addition to Trichogramma releases on plots of the first olive grove, mating disruption technique was performed once against the carpophagous generation of the same pest. The third olive grove was left without treatments for comparison. In Trichogramma releasing plots, parasitization by female wasps was mostly encountered on eggs of the jasmine moth, Palpita unionalis than on P. oleae eggs. The outcome of the combined effect of inundative releases of egg wasps with mating disruption technique was successful and could provide a model for control of lepidopterous pests of olive trees. Olive grove received both treatments characterized by lowest male catches in delta-wing traps, lowest weight of pre-mature fall of olive fruits and highest weight of fruit harvest/tree. Importantly, two different endemic Trichogramma species other than T. evanescens were collected for the first time in olive farms during the present work. Those were T. cordubensis and T. nr. Pretiosum. The new species will be mass-reared and tested during the next olive season.