Search Results (4)

Subcortical beetle communities interact with a wide range of semiochemicals released from different sources, including trees, fungi, and bark beetle pheromones. While the attraction of bark beetles, their insect predators, and competitors to bark beetle pheromones is commonly studied, the attraction of these beetle communities to other sources of semiochemicals remains poorly understood. We tested the attraction of bark and wood-boring beetles and their predators to host stress volatiles, fungal volatiles, and a mountain pine beetle lure in the field. Host stress volatiles were derived from lodgepole pine trees stressed by three fungal symbionts of mountain pine beetle and two common phytopathogens. Our results showed that bark beetles, particularly mountain pine beetles, show a preference for a combination of fungal volatiles, particularly 2-methyl-1-butanol and its lures. Without the addition of lures, 2-methyl-1-butanol was also identified as a key fungal volatile in the attraction of mountain pine beetle competitors from the Cerambycidae and Buprestidae families. Predators in the Elateridae and Staphylinidae families showed attraction to host stress volatiles and the healthy tree volatile profiles. These findings suggest that these semiochemicals warrant further field testing for potential use in monitoring and management of subcortical beetle populations. Full article

Oak decline presenting symptoms of tracheomycosis have been observed globally over long periods of time. Since the 1990s, oak decline has been considered to be a multifactorial process where abiotic predisposing factors play a significant role. Nevertheless, biotic factors, such as subcortical insects and fungal pathogens, may influence the decline process, as some insect species transmit spores of tracheomycotic pathogens. We investigated biotic agents (subcortical insects, Ophiostoma spp. and Phytophthora spp.) in six declining oak stands located within mesophytic and thermophytic zones in the Czech Republic, where five dry years occurred from 2015 to 2019. The spectrum of insect pests of oak stands was investigated using two methods: reared from logs from each stand and window traps. The presence of Ophiostoma fungi was assessed from cultivated woodblocks; Phytophthora pathogens were isolated from soil samples. In total, 2931 subcortical insect individuals were captured during the 2021 vegetation period. The most species-rich group of the subcortical insect complex involved in oak decline consisted of the families Cerambycidae: Xylotrechus antilope; Curculionidae: Scolytus intricatus, Xyleborus monographus; and Buprestidae: Agrilus biguttatus, A. sulcicollis. The presence of Ophiostoma was detected in all stands with different intensities between tree parts. Several important oak pests were positively correlated with the occurrence of Ophiostoma. On the contrary, from all soil samples, Phytophthora plurivora was found at only one studied oak stand. Based on the results, a new modified model of biotic and abiotic factors involved in the oak decline is proposed. Full article

High winds and the subsequent infestation of subcortical insect are considered to be the most extensive types of large natural disturbances in the Central European forests. In this paper, we focus on the landscape dynamics of two representative mountain areas of Slovakia, which have been affected by aforementioned natural disturbances during last two decades. For example, on 19 November 2004, the bora caused significant damage to more than 126 km² of spruce forests in the Tatra National Park (TANAP). Several wind-related events also affected sites in the National Park Low Tatras (NAPALT). Monitoring of related land cover changes during years 2000–2019 was based on CORINE Land Cover data and methodology set up on satellite and aerial images interpretation, on detailed land cover interpretation (1:10,000) for the local case studies, as well as on the results of field research and forestry databases. The dynamics of forest recovery are different in the clear-cuts (usually with subsequent tree planting) and in the naturally developing forest. The area in the vicinity of Tatranská Lonmnica encroaching on the Studená dolina National Nature Reserve in TANAP represents a trend of the gradual return of young forest. The area of Čertovica on the border between NAPALT and its buffer zone are characterized by an increase in clear-cut sites with potentially increasing soil erosion risk, due to repeated wind disasters and widening of bark beetle. Proposed detailed, large-scale approach is being barely used, when considering recent studies dealing with the natural disturbances. Full article

Acetylcholinesterase is one of the most important enzymes in living organisms, which is responsible for the synapse cholinergic and other nervous processes. However, its inhibiting effects have proven to have pharmacological applications in the treatment of different diseases, as well as in the control of insect pests; thus, the search for inhibitors is a matter of interest for biomedical and agrochemical fields. Alzheimer’s is a progressive neurodegenerative disease, which can be seen as a wide degeneration of synapses, as well as neurons, in the cerebral cortex, hippocampus, and subcortical structures. Acetylcholinesterase inhibition is an important target for the management of Alzheimer’s. Additionally, diabetes mellitus is a chronic disease with clinical manifestation of hyperglycemia, due to the ineffective production of insulin that controls the level of blood glucose. Alphaglucosidaseinhibitors could retard the uptake of dietary carbohydrates and have shown significant therapeutic effects in clinical application. Fifty-five ethyl acetate extracts from nine bacterial families from Hainan (China) were evaluated to observe their acetylcholinesterase, alphaglucosidase, and xanthine oxidase inhibitory activity. Moreover, a screening of inhibitory activity against the pathogens fungi Fusarium oxysporum and Colletotrichum gloeosporioides was performed. The best acetylcholinesterase and alphaglucosidase inhibitory activity was shown by Vibrio neocaledonicus (98.95%). This is the first report of inhibition of both enzymes by ethyl acetate extract from this strain. Full article