Monitoring and population characteristics of Prays oleae (Lepidoptera: Yponomeutidae) on different insecticidal treatments

Abstract

The presence of olive moth (Prays oleae Bern.) and effectiveness of different control treatment against it has been conducted on 160 olive trees of Leccino variety in Istria, Croatia. The treatments were: dimethoate, Bacillus thuringiensis var. kurstaki (Bt), pyrethrins, consociation of olive and planted pyrethrum and control. Olive moth has been monitored weekly using pheromone-baited delta traps and different coloured sticky plates in 12 and eight monitoring. Moth's life stages (non-destroyed, destroyed eggs and larvae) has been counted in seven monitoring. The predator activity has been determined as the ratio of destroyed eggs in the total number of observed eggs on 50 randomly chosen samples of flowers and fruits. On pheromone traps, the maximum catch has been determined on May 15th on control, when maximum of moth's flight on control, dimethoate and pyrethrins treatments coincided in time. There were more adults detected on pheromone traps then on sticky traps (16.8 times over). With time, moth's first preference was red and then blue sticky plates. The highest number of eggs ( non-destroyed and destroyed) has been found on dimethoate on May 15th ( 2.8 ± 1.1 and 4.5 ± 1.6) and June 18th ( 0.8 ± 0.5) as a consequence of accidental high oviposition rate at dimethoate plots before treatment applications. The highest number of larvae were detected on control on July 2nd ( 2.0 ± 0.7)