Spread of Scots Pine Stands Decline in Korostyshiv Forest Enterprise

The 1st International Electronic Conference on Forests—Forests for a Better Future: Sustainability, Innovation, Inter

2020

The condition of Ukraine’s forests has deteriorated sharply since the 2009 drought. The area of Scots pine stands decline has increased 2.3 times. The purpose of the research is integrating published and own data on Scots pine forest decline with the contribution of bark beetles and pointing the ways for mitigating this process. The reference materials regarding the forest stands characteristics, forest health, weather, as well as the results of own field and laboratory research were the data sources. Ips acuminatus (Gyllenhal, 1827): Coleoptera: Curculionidae: Scolytinae was the first bark beetle to infest weakened stands. The predominant development Scots pine decline in Polesie (Forest zone) is associated with a large proportion of pure pine stands of the same age, untimely thinning, and relatively slow drying of felling residues, in which the bark beetle has time to complete its development. The relative density of stocking by itself is a less important risk factor than its sudden decrease. The algorithm for prediction of bark beetles’ foci spread was developed. It will help to upgrade the accuracy of prediction, to evaluate the area of survey and control measures against insect pests. Recommendations for improving the forestry regulatory framework have been developed.

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Lessons of Scots Pine Forest Decline in Ukraine

The 1st International Electronic Conference on Forests—Forests for a Better Future: Sustainability, Innovation, Inter

2020

“…The decline of forests has occurred in the last decade in many regions of Europe (Colombari et al 2013;Andreieva and Goychuk 2018;Andreieva et al 2019). Drought and increasing anthropogenic impact led to an increase in the susceptibility of trees to colonisation by bark beetles, among which the multivoltine species Ips acuminatus (Gyllenhal, 1827) and Ips sexdentatus (Boerner, 1767) (Coleoptera: Curculionidae: Scolytinae) gained an advantage in a pine forest (Meshkova 2019(Meshkova , 2021Wermelinger et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Coleopterous predators of pine bark beetles in the last years of the outbreak recorded in Ukraine

Folia Forestalia Polonica

Vorobei²,

Omelich³

2022

The purpose of this study was to identify the species composition of coleopterous predators and their occurrence in different parts of the stem depending on the health condition of Scots pine (Pinus sylvestris L.) in the collapsing foci of bark beetles (Coleoptera: Curculionidae: Scolytinae). The research was carried out in 2019–2021 at 38 sample plots located in five State Forestry Enterprises of Sumy region (Ukraine). All sample plots are located in pure Scots pine stands in relatively poor forest site conditions. The relative density of stocking is 0.6–0.7, and the age of stands is between 60 and 110 years. The health condition for each tree was evaluated on visual characteristics by the classes: first – healthy; second – weakened; third – severely weakened; fourth – drying up; fifth – recently died and sixth – died over a year ago. Bark beetles’ nuptial chambers and predators were counted on 25 × 25 cm pallets, which were located at the lower, middle and upper parts of the stem with thin, thick and transitional bark, respectively. The significance of differences in the performance of predator species depending on the tree part, health condition and year was analysed using the nonparametric Kruskal–Wallis (K–W) test. The species composition of predators in different years, stem parts and tree health condition was compared using the Sorensen–Chekanovsky index. In the collapsing foci of bark beetles, the health condition of Scots pine in 2019–2021 tended to worsen. The infestation density of Ips acuminatus (Gyllenhal, 1827) and Ips sexdentatus (Boerner, 1767) was 0.62 ± 0.032 and 0.64 ± 0.017 nuptial chambers per 1 dm2, respectively, and also decreased in 2019–2021. In the galleries of bark beetles, seven species of coleopterous predators were collected: Aulonium ruficorne (Olivier, 1790) (Zopheridae), Platysoma elongatum (Leach, 1817) (Histeridae), Rhizophagus depressus (Fabricius, 1792) (Monotomidae), Corticeus pini (Panzer, 1799) (Tenebrionidae), Thanasimus formicarius (Linnaeus, 1758), Thanasimus femoralis (Zetterstedt, 1828) (Cleridae) and Salpingus ruficollis (Linnaeus, 1761) (Salpingidae). Two more species – Glischrochilus quadripunctatus (Linnaeus, 1758) (Nitidulidae) and Pytho depressus (Linnaeus, 1767) (Pythidae) – were singly collected in the foci. T. formicarius and P. elongatum were the most abundant. The ratio of predator–prey significantly increased from the upper to the lower part of the stem with thick bark. It, however, decreased in this stem part from the fourth to the sixth class of the health condition of the host tree.

“…Recently, in pine forests of many regions, the outbreak of multivoltine bark beetles Ips acuminatus (Gyllenhal, 1827) and Ips sexdentatus (Börner, 1776) (Coleoptera: Curculionidae: Scolytinae) have been registered (Colombari et al 2013, Meshkova et al 2017, Andreieva & Goychuk 2018, Meshkova 2021. This resulted in the sanitation felling in Scots pine stands within a large area with obtaining a poor quality timber (Selikhovkin 2017, Meshkova 2019.…”

Section: Introductionmentioning

confidence: 99%

The first results of the biological control of Ips sexdentatus using Thanasimus formicarius in Ukraine

Forest. and Forest Melior.

Ridkokasha²,

Omelich³

et al. 2021

Introduction Recently, in pine forests of many regions, the outbreak of bark beetles, particularly Ips sexdentatus (B?rner, 1776) (Coleoptera: Curculionidae: Scolytinae) have been registered. Prevention of outbreaks and decrease of the negative consequences for forest can be achieved by the use of fertilizers, insecticides, and entomophages. Thanasimus formicarius (Linnaeus 1758) (Coleoptera: Cleridae) is a predator of many coleopterous species. The aim of the research was to evaluate the first results of the release of Th. formicarius into the foci of bark beetles. Materials and Methods The study was carried out in the foci of bark beetles in Kharkiv, Sumy, and Chernigiv regions. The larvae of Th. formicarius were reared in the State Specialized Forest Protection Enterprise ‘Kharkivlisozahyst’. After that, they were moved to the forest and released. The experiment was carried out with five variants of application the fertilizer and predator, one variant of predator release without fertilizer, one variant of the fertilizer ‘Iaros’ treatment without predator release, and one variant without any treatment. The control plots were of three types: K-1 – release of predator larvae without applying a fertilizer; K-2 – treatment with fertilizer without the release of predator; K-3 – without treatment with fertilizer and without the release of predator. The change in the health condition of trees and bark beetles’ survival were the criteria for evaluating the treatment effectiveness. Results and Conclusions The efficiency of different combinations of treatment with fertilizer and the release of the predator, evaluated by the change of the health condition of viable trees, was from 14.7 to 28.3%. According to the 2020 assessment, the density of larval galleries of the bark beetle decreased in all plots compared to 2018. The more rapid collapse of bark beetle outbreak as compared to the control was registered for the plots with predator release. The release of the predator along with the use of mineral fertilizer by spraying the crowns provided a more significant improvement in the stand health condition and a decrease in the viability of the bark beetle populations than the only predator release.