Determination of hazelnut bud mite species and contamination rate in hazelnut orchards in duzce province

This study was carried out in a total of 40 orchards during the vegetation period of November 2021-June 2022 in order to determine the harmful hazelnut bud mite species and the contamination rate in the hazelnut orchards in the three districts (Akçakoca, Merkez and Cumayeri) where hazelnut cultivation is most common in Duzce. Taking into account the size of the hazelnut orchards, the organs of the tree such as leaves, shoots, buds, flowers and fruits were examined by visual control method in at least 10 randomly selected quarries in each orchard, and the collected samples were brought to the laboratory with polyethylene bags and recorded. Species identification was made by preparing the preparations of the individuals obtained. In addition, in the samplings, buds were counted in at least 10 quarries in each orchard and on a branch selected from each quarry. When a single individual or damage of the pest is detected in the sampled gardens, that garden was recorded as contaminated and the infection rate was determined. In the study, Phytoptus avellanae Nal. (Trombidiformes: Phytoptidae) and Cecidophyopsis vermiformis (Nal.) (Trombidiformes: Eriophyidae) were identified. Species P. avellanae represent a complex of two cryptic species. In all three districts, it was determined that the pest contamination rate was 100% in the hazelnut orchards and the bud density was above the economic damage threshold. The highest average of cones per branch in the gardens was found in Cumayeri district (16,4 cone number/branch), followed by Akçakoca district (6,5-9,25 cone number/branch) and Central district (7,16-8,85 cone number/branch). It has been observed that the hazelnut bud mite population is at a level that requires control and it is among the important factors affecting the yield of hazelnut in recent years.