Beetles and nematodes associated with wither Scots pines

Abstract

This study focused on the occurrence of xylophagous beetles and nematodes in the different parts of Pinus sylvestris L. trees of different health condition in the pure stands in Zhytomyr region (Central Polissya). Stem fragments with thin, thick and transitional bark, branches and twigs were examined in each of 12 model trees. Xylophagous beetles were identified by adults or by galleries. Nematodes were isolated from wood samples in the laboratory using the Baermann method and identified by morphometric characteristics. Among 10 species of xylophagous beetles, Ips acuminatus (frequency 16.7%; dominance 17.9%) and I. sexdentatus (frequency 11.1%, dominance 54.6%) dominated, which prefer the fragments with thin and thick bark respectively. No xylophagous beetle was found in the healthy and slightly weakened trees. Among 15 nematode species, 40% were saproxylic, 33.3% entomophilic, 13.3% phytophagous, and by 6.7% predators and species associated with fungi. An entomophilic nematodes Cryptaphelenchus macrogaster f. acuminati was common in all parts of stem and branches (frequency of occurrence 25–33.3%). An entomophilic nematodes Parasitorhabditis acuminati and a predator Fuchsia buetschlii acuminati had the highest frequency of occurrence (41.7%) under the thin bark and in the branches. The frequency of these species in colonized with xylophagous insects stem fragments with thin bark was significantly higher than in respective not colonized fragments.

Forest site conditions and the threat for insect outbreaks in the Scots pine stands of Polissya

“…Scots pine (Pinus sylvestris L.) is the most spread forest tree species in Polissya (Buzun et al, 2018) and the most damaged by foliage browsing and stem insects (Andreieva et al 2018(Andreieva et al , 2020Meshkova 2019).…”

Nematodes in the Pine Forests of Northern and Central Greece

“…Many of the free-living nematode taxa recovered in the present study have also been reported to be associated with insects, in addition to their initial trophic group assignment [42,[104][105][106] such as members of the families Aphelenchoididae, Rhabditidae, Neodiplogasteridae, and Panagrolaimidae [42,95,107]. O. erosus, H. ligniperda, T. piniperda, and I. sexdentatus, as well as Hylastes linearis Erichson 1836 and Pissodes castaneus De Geer 1775, have all been found to carry nematodes belonging to different genera of the Aphelenchoididae family or other taxonomic groups.…”

“…within a host tree, sampling effort should aim at screening different parts of the same tree. Even though Bursaphelenchus species have been recovered from all parts of the tree, occurrence frequencies can differ [95]. Specifically, Bursaphelenchus spp.…”

Morphological and Molecular Characterization of Diplogasteroides sp., a Cryptic Population of the Haslacheri Group (Diplogastridae), and Parasitorhabditis terebranus (Rhabditidae) from Korea

“…Xylophagous insects, mainly the longhorn beetles (Cerambycidae), bark beetles from subfamily Scolytinae (family Curculionidae), and jewel beetles (Buprestidae) represent the most economically important agents of tree decline in pine ecosystems ( Wood, 1982 ; Sauvard, 2007 ; Meshkova et al, 2018 ; Andreieva et al, 2020 ). For instance, the genus Monochamus (Cerambycidae) is best known for its fundamental role in the epidemiology of pine wilt disease ( Mamiya, 1983 ).…”