Determination of population dynamics, natural enemies and overwintering of colorado potato bettle, leptinotarsa decemlineata (say.) (Coleoptera: Chrysomelidae) in Bolu province, Turkey

This study was carried out in 4 potato fields in the center of Bolu between 2020 and 2021. In the study, the population of the Colorado potato beetle Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae), one of the most important pests of potatoes, was monitored, and determined its natural enemies, and revealed its overwintering. Colorado potato beetle was detected in potato fields on 14 May in 2020 and on 18 May in 2021. The pest entered the wintering period on 11 October in 2020 and on 05 October in 2021. The peak period when the adult and larval stages of the pest reached the highest population is july-august, when the pentate air temperature averages reach the highest level of both year. It was determined that Colorado potato beetle may occur 2,75 offspring per year in Bolu province according to development threshold and thermal constant (a degree day). Chrysoperla carnea Stephens (Neuroptera: Chrysopidae) and Semiadalia undecimnotata Schneider (Coleoptera: Coccinellidae) species were determined as predators of the pest. No parasitoids were detected from the egg, larva, and adult stages of the pest. It has been determined that the adults of the pest overwinter in the soil between the second week of october and the third week of may in the first year, and between the first week of october and the second week of may in the second year. In the correlation analyzes between the data obtained in the population dynamic and the weekly air temperature averages, there was a moderate correlation between adult numbers and the weekly temperature averages in the first year; a high correlation was found between the number of adults and weekly temperature averages in the second year, and a moderate correlation for the number of larvae.