Control of oriental fruit moth, Cydia molesta, in the peach orchards of South-Eastern Bulgaria, using CIDETRAK® OFM-L dispensers

Abstract: Oriental fruit moth (OFM), Cydia molesta (Busck) (Lepidoptera: Tortricidae), is an economically important pest of peach, nectarine and apricot in Bulgaria. Its larvae cause damage, infesting shoots and fruits. The aim of this study was to test the effectiveness of mating disruption (MD) in control of OFM in peach orchards, using CIDETRAK® OFM-L dispensers of Trécé Inc., USA. The trials were carried out in South-East Bulgaria in 2009-2011. The trial (MD) plots were located in three different 2-ha orchard blocks in the Sliven district. The damage of shoots was evaluated during the first generation of OFM on 20 trees, randomly selected within the central area of each block. The fruit damage was recorded accordingly, on 100 fruits per each selected tree; so, 2,000 fruits were inspected for damage in each block. The rate of damage in the trial plots was compared with that in the reference orchard, located in the vicinity, treated with conventional pesticides. CIDETRAK® OFM-L dispensers completely inhibited OFM captures in the pheromone traps, installed in the trial plots, indicating a high level of disruption. The percentage of shoots infested by OFM larvae was nil in the MD plots. The three-year data of fruit damage rate were subjected to the analysis of variance, considering successive years of study as replications. The rate of damage in the MD plots was low, below 1%. The difference in the percentage of damaged fruits between the reference orchard and the trial plots was highly significant for all cultivars under study; it was, however, greater in late than in early or mid-season cultivars. The considerable fruit damage noted in the reference orchard, in spite of many chemical treatments applied, indicates that commonly used organophosphates and pyrethroids have become ineffective against OFM. Probably OFM developed resistance to the insecticides used. On the other hand, the present results do confirm that mating disruption, using CIDETRAK® OFM-L dispensers, can provide a more effective control of oriental fruit moth. Implementation of this method in the commercial peach production in Bulgaria would be helpful in preservation of sound environment and in avoiding any risk of pollution of fruit products with pesticides.