Control of oriental fruit moth, Cydia molesta Busck and peach twig borer Anarsia lineatella Zell. using reduced rate of pheromone dispensers
Abstract: The main pest on peach in Bulgaria is the oriental fruit moth (OFM), Cydia molesta (Busck) (Lepidoptera: Tortricidae). The trials were carried out in the years 2016-2018 in an isolated peach experimental orchard of 1 ha in the Fruit Growing Institute, Plovdiv – Central South Bulgaria. Mating disruption (MD) was tested as an alternative method for controlling OFM and peach twig borer (PTB) Anarsia lineatella (Zell.) (Lepidoptera: Gelechiidae) from post-bloom till harvest. The aim of this study was to test the effectiveness of MD in control of OFM and PTB in peach orchards, using CIDETRAK® OFM/PTB MESO dispensers of Trécé Inc., USA, at a rate of 20 dispensers per ha. Monitoring of OFM and PTB flights was carried out using sex pheromone trapping in the years of the study. PHEROCON® VI Delta sticky traps were installed in the trial orchard using a scheme provided by the producer. The damage to shoots was evaluated during the first generation of OFM and PTB on 20 trees, randomly selected within the central area of each block. Correspondingly, fruit damage was recorded on 100 fruits per each selected tree; so, 2000 fruits were inspected for damage from both pests in each block. The level of damaged fruits in the trial plots was compared with that in a reference orchard, located in the vicinity, treated with conventional pesticides. The fruit damage by OFM, in the reference orchard, ranges from 2.9 to 3.7% and by PTB from 1.2 to 1.4% in the successive years. Percentage of damage in the experimental orchard treated with CIDETRAK® OFM/PTB MESO™ was 0.1% by OFM and 0.1% by PTB, which was rather below the economic threshold. The significance of differences in the damage level between the trial and reference orchards was estimated by use of Chi-square tests. CIDETRAK® OFM/PTB MESO™ is effective when used at a dosage of 20 dispensers per ha, applied once during the season, before the first onset of OFM and PTB. The use of CIDETRAK® OFM/PTB MESO™ shows that the number of dispensers used does not affect the effectiveness of mating disruption and the reduced rate of dispensers used will help the growers to decrease labor in the field. Applications of these dispensers can provide an effective control of oriental fruit moth and peach twig borer, with better results than the conventional protection programs employed currently in Bulgaria.