www.nature.com/scientificreports OPEN Damage severity of wood‑destroying insects according to the Bevan damage classifcation system in log depots of Northwest Turkey Mesut Yalcin1, Caglar Akcay1*, Cihat Tascioglu1, Besir Yuksel2 & Ali Kemal Ozbayram2 The aim of the study was to determine damage severity of wood‑destroying insects on logs stored in forest depots. The Bevan damage classifcation (BDC) system, developed in 1987, was utilized to determine damage severity in log depots in 21 locations throughout seven provinces in Turkey. Pheromone traps were placed in those locations at the beginning of April in 2015 and 2016. Furthermore some stored wood within the log depots were checked and split into small pieces to collect insects that damage wood. The BDC system was used for the frst time to measure the severity of insect damage in log depots. Twenty-eight families, 104 genera and 123 species were identifed in this study. Based on the BDC system, the highest damage was found from the Cerambycidae and Buprestidae families. Arhopalus rusticus was determined as the insect responsible for the highest amount of damage with 8.8% severity rating in the pheromone-trapped insects group. When the stored wood material was considered, Hylotrupes bajulus was found to be the cause of the highest damage. The lowest damage values were among the predator insects (Cleridae, Trogossitidae, Cantharidae) and those feeding on fungi colonized on the wood (Mordellidae, Cerylonidae, Nitidulidae). Some other predator insects of the Tenebrionidae family (Uloma cypraea, Uloma culinaris, Menephilus cylindricus) and Elateridae family (Lacon punctatus, Ampedus sp.) exhibited relatively higher damage severity values since they had built tunnels and made holes in the stored wood material. When the environmental factors were considered, the Buprestidae family exhibited a very strong positive relationship (p < 0.005) with insect frequency distribution (r = 0.922), number of species (r = 0.879) and insect density (r = 0.942). Both families showed the highest number and frequency during July and August, highlighting the importance of insect control and management during these months. Insects are one of the most important biological factors that destroy wood materials1. Insects from the Ceram- bycidae, Anobiidae, Lyctidae, Buprestidae and Melandryidae families cause damage to logs and lumber that lowers technical specifcations, leading to major economic losses 2. Te Tenebrionidae, Elateridae, Lucanidae and Scarabaeidae families, on the other hand, produce their larvae on long-term stored wood and partially decayed wood material3. Te Cleridae and Trogossitidae families are common since they are predators of wood-destroying insects4–6. Insects from the Curculionidae/Scolytinae families destroy wood at every stage from stump to log7. Insects from the Cerambycidae family cause damage on both sofwood and hardwood species. Teir major destruction takes place during the larval stage8. Some species of Cerambycidae damage ornamental and fruit trees, while other species harm newly harvested trees, inner bark, decaying wood, dried wood and furniture in use9–11. Some species are considered invasive for some locations, making protective and control measures very difcult12. Tey top the list among insects that are economically harmful for wood material13. 1Department of Forest Products Engineering, Faculty of Forestry, Duzce University, 81620 Duzce, Turkey. 2Department of Forest Engineering, Faculty of Forestry, Duzce University, 81600 Duzce, Turkey. *email: [email protected] SCIENTIFIC REPORTS | (2020) 10:13705 | https://doi.org/10.1038/s41598-020-70696-6 1 Vol.:(0123456789) www.nature.com/scientificreports/ Figure 1. Map showing the log depots in the study areas (Provinces: 1-Duzce (DU), 2- Bolu (BO), 3-Zonguldak (ZO), 4-Bartın (BR), 5-Kastamonu (KS), 6-Karabuk (KR) and 7-Sinop (SI). Letters on the map are the codes of the log depots in the provinces of the study area. Te map was plotted using by ArcGis 10.3 version which is used for mapping and editing tasks). Insects from the Buprestidae family can survive under high temperatures that other insects cannot tolerate14. Adults do not cause major damage to fowers. Teir larvae, however, heavily attack the bark, cambium and wood portions of sof and hardwoods9,15. Tey exhibit high reproduction rates on partially burned trees afer forest fres. Generally, they are considered as secondary harmful insects; however, if they cannot fnd a proper food source, they became primary harmful insects. Te Buprestidae family is an important family with a high number of species creating major damage on forest and wood products 16. Te Anobiidae family of insects can damage both sof and hardwoods. Tey generally attack sapwood, and occasionally hardwood. Tey can turn construction wood into a sponge-like material, thus causing heavy dam- age. Te most important species of this family are Anobium punctatum (furniture beetle), Xestobium rufovillosum (deathwatch beetle)17, Ptilinus pectinicornis (fan-bearing wood-borer) and Ernobius mollis (pine bark anobiid or pine knot borer)18. Scolytinae (Curculionidae) (bark beetles) are secondary harmful insects that prefer trees weakened due to wind and snow load, forest fres, drought or infestation by other insects19. Even though they are considered secondary harmful insects, they tend to turn into primary harmful insects during their maturation into young adults by attacking healthy trees. Te bark beetles harm bark, outer sapwood and cambium zones. Ambrosia beetles are an important member of this subfamily and cause degradation via fungus transfer20. Insects from the Elateridae and Tenebrionidae families live in decaying wood material and dead or living vegetation in forested areas and are known as predators21. Log depots are storage facilities for logs harvested from the forest until they are sent to the fnal consumers. During this storage time, the wood is attacked by insects, resulting in major economic losses22,23. In order to manage these harmful insects and reduce the scale of damage to the wood, identifcation of the insect species in the storage areas must be carried out. Most previous studies have focused on insects causing damage to living trees rather than on harvested material held in outdoor storage. Terefore, the current study aimed to investigate and identify the insect species causing economical loss to industrial wood material in log depots. Insects were collected via a unique pheromone trap. Additionally, the Bevan damage classifcation system was utilized for the frst time to calculate economic losses. Te insect frequency, insect number and species number of wood- destroying insects based on provincial locations were determined and their relation with the environmental factors was discussed. Material and methods Study areas. Te map in Fig. 1 shows the 21 log storage facilities of the seven provinces covered in the study, including Duzce (DU), Bolu (BO), Zonguldak (ZO), Bartın (BR), Kastamonu (KS), Karabuk (KR) and Sinop (SI) in Northwest Turkey. Te current study took place in these 21 log depots in provinces located in the Western Black Sea Region of Turkey. Te log depots were selected on the basis of the amount of stored wood and number of diferent wood SCIENTIFIC REPORTS | (2020) 10:13705 | https://doi.org/10.1038/s41598-020-70696-6 2 Vol:.(1234567890) www.nature.com/scientificreports/ Log Depot Code Aspect Altitude (m) Distance to forest (m) Forest type at depot site 1a E 199 > 3,000 – 1b NE 129 > 3,000 – 1c NW 289 < 3,000 Deciduous 2d S 1,166 < 3,000 Coniferous 2e NE 794 < 3,000 Coniferous 2f. NW 690 < 3,000 Coniferous 2 g S 1,270 > 3,000 – 3 h SW 39 > 3,000 – 3i S 19 < 3,000 Deciduous 4j N 506 < 3,000 Deciduous 4 k SW 538 > 3,000 – 4 l SW 785 > 3,000 – 5 m SW 308 < 3,000 Coniferous 5n SW 71 < 3,000 Coniferous 5o NE 35 < 3,000 Coniferous 6p W 431 > 3,000 – 6r W 657 > 3,000 – 6 s F 603 < 3,000 Coniferous 6t NE 604 < 3,000 Coniferous 7u F 342 > 3,000 – 7v F 277 < 3,000 Coniferous Table 1. Log depot details: aspect, altitude and distance from forest areas. E: East, W: West, N: North, S: South, F: Flat. species. Te highest numbers of wood species were identifed in log depots 1a and 1b. Table 1 presents details of the log depots such as their aspect, altitude and distance from forest areas. Installation of insect collection cages in log depots. At the beginning of the April 2015 and 2016, a single insect collection cage was installed in each of the 21 log depot facilities. Te cages were then collected at the end of October of the mentioned years. Each cage was equipped with a data logger to measure the tem- perature and relative humidity within the cage environment. During the study, monthly average temperature and relative humidity values at each cage location were recorded. Tese data were later correlated with insect frequency, species number and insect density of the Cerambycidae and Buprestidae families. Furthermore, a mixture of trans-verbenol (100 mg) + myrtenol (100 mg) + alpha pinene (20 mg), Ipsdienol (140 mg), Ipsenol, 2-methyl 3-butene 2-ol and cis-verbenol was used as a pheromone entrapment agent. Te cages were newly developed24 and had some features that difered from the standard Scandinavian insect collecting cages. In production, the stainless steel gusset of the cages were cut to 50 × 50 × 50 cm and were joined in cubic way by spot welding. Afer this stage, stainless steel AISI 304 wires are cut according to gusset dimensions and were connected to gussets by using spot welding. Te neck region where the collection containers were placed was connected on the welding machine. Cage covers were designed and manufactured to ft the frame system on a separate line. Finally, the cages were integrated to Scandinavian type three funnel trap system (Fig. 2). Tese cages occupy a much larger area so that the entrapped insects can hide easily from their predators.