The behaviour of codling moth (Lepidoptera: Tortricidae)in the Croatian apple orchards

Abstract: The codling moth, Cydia pomonella (L.), is the most important pest in appleproduction in Croatia and abroad. The pest is very adaptable to different climatic conditions andis known for the development of resistance to several chemical groups of insecticides. Because ofthese reasons, the populations of codling moth are differentiated in many ecotypes of variousbiological and physiological development requirements.Following the dynamics and abundance of codling moth butterflies in the past ten years inCroatia the differences in the behaviour of this pest were observed. In the past ten years theappearance and the flight of codling moth butterflies have been monitored by using pheromonetraps (Csalomon) always placed in the same position and observed every two days. In this paperdata from the 2000, 2008 and 2009 were analyzed. The research results showed earlierappearance of butterflies in the vegetation season (in the 2000 butterflies began appearing in lateApril, while in 2008 and 2009 they appeared in mid-April). Furthermore, the flight of butterfliesin the vegetation seasons in 2008 and 2009 lasted several days more than in 2000. In the last twoyears, the total number of caught butterflies has increased (2000 – 165 specimens, 2008 – 326specimens and 2009 – 451 specimens) as well as the maximum daily number of caught butterflies(2000 – 14 specimens, 2008 and 2009 – 33 specimens). The average number of caught butterfliesin 2000 was 4.46 specimens, in 2008 – 7.09 specimens and in 2009 – 10.7 specimens.The possible causes for these modifications could be the climate changes that allow betteroverwintering of pests, longer period of development in the vegetation season or possiblemodifications in the genetic structure of treated and untreated codling moth specimens evidencedby recent genetic studies.