Current Problems of Forest Protection (25–27 October 2022, Katowice Poland)

Abstract

Forestry is one of the sectors particularly affected by the threats posed by changing climatic conditions. This is reflected in the deterioration of the health status of stands due to the synergistic effect of numerous abiotic and biotic factors. Current forest health problems are due to dynamic, negative changes in the forest environment. While the amount of precipitation remains at a similar level, its distribution varies throughout the year and, in particular, the lack of soil moisture during the growing season leads to the weakening of trees, including the main forest-forming species in Poland such as Pinus sylvestris. The weakening of trees, in turn, leads to species of insect pests that were previously considered secondary becoming primary pests, such as Ips acuminatus. It is likely that weakening of trees also favours increased occurrence of parasitic plants such as Viscum album ssp. austriacum or Loranthus europaeus. Infestations of the hemiparasitic, xylem-secreting pine mistletoe are of great interest because they are spreading rapidly throughout Europe. Drought in forests is not only a long-term water shortage, but also a situation in which plant-fungal relationships are disrupted. Reduced water availability leads to a number of negative changes in the soil and the mycobiota that live there, affecting entire ecosystems. The effects of climate change and increased international trade are leading to the spread of pathogenic fungi and other harmful organisms whose range was previously restricted to the south of our continent. Unfavourable abiotic and biotic factors leading to weakening of oak stands in the western part of Poland have resulted in activation of new pests like Mediterranean oak borer. Intensification of transport and shortening of its duration, as well as climatic changes, favour the introduction of various organisms, including bark beetles (Scolytinae). In Poland, cyclic insect outbreaks are one of the most important problems in forest protection. Developing methods to monitor, prevent outbreaks and control the density of insect populations below harmful levels can be a challenge to consider. Finding an innovative system for applying insecticides to control spruce bark beetle could also be an interesting solution, where insects attracted to pheromones die after contact with the insecticide. Contact with the insecticide has a dual effect: either directly when the tree is treated, or when the bark beetle attempts to invade the tree. Opportunities for the use of biostimulants in forestry and is an attractive way to regenerate plants after negative stressors such as frost, drought or damage caused by improper use of pesticides, as well as the negative effects of diseases and pests. It acts indirectly by stimulating leaf, stem and root development and improving nutrient uptake. The effects of chemical treatments on fungal biodiversity in forests should be studied using powerful molecular tools such as NGS.

1. Introduction

From 25–27 October 2022, a conference entitled “Current Problems of Forest Protection—2022” was held at the Radisson Inn Hotel in Katowice, organized by the IBL Forest Protection Department and the Polish Forest Society in cooperation with the Regional Directorate of State Forests in Katowice and the Katowice Forest Inspectorate.

The conference continued the long tradition of meetings on forest science and practice, where current issues of forest protection against insects, pathogenic fungi and animals were discussed. The meeting was attended by nearly 100 people, including representatives from:

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The Department of Forest Protection of the General Directorate of State Forests (DGLP) and forest protection teams;

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Regional Directorates of State Forests (RDLP) and forest inspectorates;

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The Universities of Life Sciences in Poznań and Wrocław, Warsaw University of Life Sciences and the University of Adam Mickiewicz in Poznań, and the Chemipan Experimental Department of the Institute of Physical Chemistry of the Polish Academy of Sciences;

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Kampinowski National Park;

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Companies from the field of forest protection, including: Agrarius, Andrzej Barczyk FPHU TIM, Score sp. z o.o., Silvana Eco Solutions sp. z o.o. and SPOTTA from the United Kingdom.

On the first day of the conference, the participants were introduced by Professor Krzysztof Stereńczak—Director of the Forest Research Institute and Jurand Irlik—Deputy Director of the RDSF in Katowice, who presented the main issues of forest management and, especially, forest protection in Upper Silesia.

The first lecture session started with a presentation by Aldona Perlińska, Head of the Forest Protection Department in the Forestry Directorate, who presented the main problems of forest protection at the national level. Special attention was paid to the weakening of pine and hardwood stands due to the worsening drought since 2015, and the resulting problems with secondary pests and pathogenic fungi. In addition, she pointed out the increasing likelihood of the appearance of new insect and fungal species in our country, which are typical of areas with higher air temperatures. Their appearance, as a result of climate warming, could be invasive in Poland, so continuous monitoring of the presence of these organisms is needed. The next papers of the first session dealt with the history of insect occurrence in the areas of the RDSF in Gdańsk and Toruń, as well as with the negative impact of soil moisture decline on the function of ectomycorrhizal fungi.

In the second session, six presentations were given on the occurrence of new insect species and tree diseases in the country, which have gained economic importance due to climate change. The occurrence of semi-parasites on trees (Loranthus europaeus Jacq. and V. album ssp. austriacum) and their impact on host plant health were also discussed. The results of the entomological survey in the forests of the RDSF in Krosno were also presented.

The third and fourth sessions were characterized by presentations on the possibilities of using both non-chemical and innovative chemical methods in modern forest protection against insects and fungal diseases. A system of detectors for monitoring the pine weevil in forest crops was presented. Other presentations dealt with the resistance of ash trees to fungal diseases and monitoring of selected elements of pine production in container nurseries, as well as their impact on the quality of planting material. The fourth session presented a model that allows for medium-term prediction of the onset of nun moth Lymantria monacha spread, as well as issues related to Acantholyda posticalis monitoring. The conference concluded with papers summarized in the fifth session on the biology and ecology of various insect species.

The field part of the conference was organized so that the participants could get acquainted with the current problems of forest protection in Katowice Forest District (mining damage in Ochojec Forestry, poisoning site in Hamerla Forest Settlement, “Las Murckowski” reserve). As part of the promotion of the region, the conference participants visited the Silesian Museum in Katowice.

History of Insects Occurrence in Gdańsk and Toruń, and Current Problems of Forest Protection

Piotr Gawęda

General Directorate of the State Forests, Forest Protection Team in Gdańsk, Poland

*

Correspondence:

Abstract: The history of insect occurrence was separately prepared for the Regional Directorates of State Forests in Gdańsk and Toruń. It contains information on the main insects subject to pest control since the late 1940s. Thirty-six insect species are described in it. The highly detailed data are based on documents accessible to the Forest Protection Team in Gdansk. The uniform tables list the most important pests, such as the nun moth (Lymantria monacha) or the pine moth (Panolis flammea), and other important insects. You can see the list of forest districts, the area of pest control, the dose of chemical or biological preparations used, the effectiveness of the measures and the number of different insect stages. A lot of useful information is added below the tables. The material is supplemented by maps showing only the locations of primary pest control. Three tables of contents make the study easily searchable. All outbreaks were evaluated. This made it possible to divide forests into problem and non-problem areas. The next step was a limited number of points to monitor insects under trees in the fall. In addition, information on the timing of pest control helps in planning future pest control. Existing methods for predicting the occurrence of insects, such as the pine sawfly (Diprion pini), are not perfect. Therefore, this study proves to be particularly useful as it accurately indicates which areas to control in the event of a threat based on documented history.

Keywords: outbreak; forest; occurrence; control; defoliating insects

Effects of Drought on the Interaction between Woody Plants and Fungi

Dorota Hilszczańska and Hanna Szmidla

Forest Research Institute, Sękocin Stary, Poland

*

Correspondence:

Abstract: Maintaining healthy forests under conditions of global climate change is one of the greatest challenges facing foresters. Although precipitation intensity and frequency increased in the Northern Hemisphere during the second half of the 20th Century, many areas were also affected by drought. Drought in forests is not only a prolonged water shortage, but also a situation in which plant-fungal relationships are disrupted. Limited water availability leads to a series of unfavorable changes in the soil and in the mycobiota inhabiting it, thus affecting entire ecosystems. Conclusions from studies conducted to date are clear, emphasizing the negative effects of reduced soil moisture on the function of ectomycorrhizal fungi and the positive effects on stimulating and promoting the development of some fungal endophytes and pathogens, as well as some semiparasitic plant species (e.g., the genus Viscum). We highlight here the role of mycorrhizal and endophytic fungi in mitigating the effects of soil water deficiency and the impact of their altered activity during periods of drought on tree health. The presented topics show the fundamental role of mycorrhizal mycelium in supporting water transport to the plant, and the course of processes occurring in trees (dieback, development of infectious diseases, biology of endophytes), under the influence of drought, were presented.

On the basis of the extensive literature, the following conclusions and recommendations for practice were formulated.

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The role of mycorrhizal fungi is to stabilize the ecosystem; therefore, the selection of drought-resistant tree genotypes and mycorrhizal fungal species is necessary for future forest management.

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The protection of old trees, and thus, the forest microbiota, is one of the issues to reduce the negative effects of drought.

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Mycorrhization of seedlings with mycorrhizal fungi with hydrophobic mycelium, such as Scleroderma spp. or Rhizopogon spp., is worth considering under the current climatic conditions.

In conclusion, the challenges caused by climate change may lead to a change in the main objective of forest management, going far beyond the mere maintenance of natural functions of the forest. Therefore, climate change may force the development of entirely new models of forest management. Guy Ryder-UN-Water Chair at the 24th UN -Water meeting in Geneva 2016 stated: “There is no life without water”—but this is not the whole truth–“There is no forest without fungi” and any effort to improve forest conditions must take into account the status of local mycobiota.

Keywords: water deficit; mycorrhiza; pathogens; endophytes; forest dieback

Occurrence of New Diseases Promoted by Climatic Changes

Tomasz Oszako, Hanna Szmidla and Iwona Skrzecz

Forest Research Institute, Sękocin Stary, Poland

*

Correspondence:

Abstract The effects of climate change and increasing international trade are leading to the spread of pathogenic fungi and other harmful organisms whose range was previously limited to the south of our continent. In Poland, Phytophthora cinnamomi has been found in nurseries of ornamental plants and in the rhizosphere of oak stands on the Krotoszyn plateau, which is of great concern as it is involved in the death of cork oaks in Portugal and Spain, and, in Australia, it destroys both understory plants and mature eucalyptus stands. It is capable of attacking more than 1000 plant genera and species. We are also threatened by diseases that cause stem cankers of chestnut, sessile oak (Cryphonectria parasitica) and pine (Fusarium circinatum) in southern Europe. The bacterium Xyllela fastidiosa has been identified as the cause of olive dieback in Italy, but oaks may also be potential hosts. Therefore, in vivo testing must be conducted in advance to know which of our native species are at risk. The species P. ramorum, which causes sudden oak dieback on the North American continent, unexpectedly threatened larches when it was introduced to the west of the United Kingdom. The spread of alien invasive organisms sometimes occurs so rapidly that they are not included in the so-called quarantine lists, as in the case of ash dieback and Hymenoscyphus fraxineus. The disease has now spread across the continent, and the emerald ash borer, Agrillus planipennis, is migrating from the east and killing ash trees. If we use pesticides and provide adequate irrigation and fertilization, disease symptoms often do not present in the nursery. However, using DNA analysis, we can detect the presence of pathogens in plant tissue, soil or irrigation water. Clearly, an early warning system is needed, and forest managers have been developing it themselves. If a foreign pest is not detected and eradicated early, both the cost and the amount of infested plants and acreage will later increase. Recently, we have become aware of Phytophthora spp. spreading through natural pathways, such as waterways or bird migration. Knowing the pathogen species in the soil allows foresters to seed plants that are resistant to these pathogens to prevent disease. To limit the spread of pathogens, machinery, tools, tyres and shoes should be washed and disinfected between treatments in different areas of the nursery. Disinfectant-soaked mats should be standard at the entrance and exit of the nursery.

Keywords: aliens; pests; nurseries; DNA tests; disinfection

New Species of Bark Beetles in the Fauna of Poland—New Challenges for Forest Protection?

Radosław Witkowski, Andrzej Mazur, Jolanta Behnke-Borowczyk and Natalia Kartawik

Poznań University of Life Sciences, Poznań, Poland

*

Correspondence:

Abstract: The intensification of transport and the shortening of its duration, as well as climate change, favour the introduction of various organisms, including bark beetles (Scolytinae). As a result of various types of inventories and monitoring, five new bark beetle species have been discovered in Poland in the last decade, bringing the number of species considered alien to nine.

One of them is Gnathotrichus materiarius, which grows on conifers, but prefers pines and spruces. In Poland, the species was first detected in 2015 in the southwestern part of the country (Regional Directorate of State Forests in Wrocław). Based on the data on the occurrence of the species, a model was developed indicating areas with optimal climatic conditions for the development of the species. In addition, a forecast of the species’ distribution for the period 2061–2080 was prepared.

Other alien species colonising oaks and/or ash bark beetles (e.g., Phloeotribus caucasicus) are other factors that will contribute to the decline of the species. It should also be noted that pathogens can be transmitted by insects that pose an additional threat to forest stands.

High temperatures and long periods without rain cause physiological stress in trees, making plants susceptible to disease and insect colonisation. Poor tree conditions create favourable conditions for the development of various insects, including alien and invasive insects. Invasion dynamics depend on many abiotic and biotic factors; therefore, this process is diverse and difficult to predict. Therefore, it is important to monitor populations of these species to minimise negative impacts on the environment and economy.

The research presented shows that monitoring is an important tool for collecting data on native and alien species, which provides the basis for developing conservation measures.

Keywords: alien species; insect pests; bark and ambrosia beetles

Loranthus europaeus—A New Challenge for Silviculture and Protection of Deciduous Stands in Poland?

Marlena Baranowska, Adrian Łukowski, Robert Korzeniewicz, Wojciech Kowalkowski and Łukasz Dylewski

Poznań University of Live Sciences, Poznań, Poland

*

Correspondence:

Abstract:Loranthus europaeus Jacq. (Oak Mistletoe) is a semi-parasitic plant that mainly attacks oaks. It usually occurs as a medium-sized shrub that deprives the host plant of water, minerals and organic compounds. Loranthus europaeus restricts the process of photosynthesis and respiration of host plants. Trees colonised by this mistletoe are more susceptible to the influence of stress factors, the effect of which accelerates the death of the trees. Heavily infested trees respond with premature crown ageing, which can eventually lead to tree death.

Information on the occurrence of L. europaeus in Poland is contradictory. Some sources state that this mistletoe has not been recorded in Poland, while others state that it was seen over 130 years ago near Częstochowa, Busko, Bukowina. Oak mistletoe was mentioned in a 19th Century publication by Władysław Spaust, who confirmed that the plant was rare in present-day Poland. In recent years, this species has not been studied in Poland.

Currently, a high population density of L. europaeus is found in neighbouring countries of Poland: Slovakia and the Czech Republic. Its occurrence has also been confirmed in Germany and Ukraine. The occurring climatic changes increase the probability of L. europaeus spreading. The type of host plant, age, origin and biosocial status are probably also important. The presence of this mistletoe may be influenced by habitat fragmentation, herbivory and topography. The spread of this species is favoured by ornithochory. The fruits of mistletoe are fed to various bird species, which transport them over long distances.

Considering the threat that L. europaeus poses to oak stands in Poland, it is important to create a model of the potential occurrence of this mistletoe in case of subsequent climate changes. An inventory of stands on the border between Poland and Slovakia and between Poland and the Czech Republic is important as part of the risk assessment of this semi-parasite. Continuous monitoring should be conducted to determine how to most effectively reduce the incidence of L. europaeus. The risk should not be ignored, especially in a situation when the area of mistletoe in coniferous stands is expanding and the share of hardwood stands in the forest area of our country is increasing.

Keywords: oak mistletoe; climate changes; semi-parasitic plant; deciduous stands

Taxonomic Status of Mistletoe Found in Pinus sylvestris Stands in Poland Based on Molecular Studies

Katarzyna Sikora

Forest Research Institute, Sękocin Stary, Poland

*

Correspondence:

Abstract: Forestry is one of the sectors particularly affected by the threats posed by changing climatic conditions, as evidenced by a deterioration in the health of tree stands due to the synergistic effect of numerous abiotic and biotic factors. Of particular importance in the context of the observed changes in the health status of Pinus sylvestris stands is the mass occurrence of mistletoe (Viscum album L.), which in the past was of little economic importance.

Based on the diversity of host plants and the biochemical and genetic characteristics of mistletoe, three subspecies within Viscum species have been identified to date, only one of which, V. album ssp. austriacum, can parasitize on Pinus. The process of new species formation or speciation may occur as a result of parasite adaptation to the host race. The studies conducted so far have shown the taxonomic distinctiveness of mistletoe at the subspecies level, adaptation to the host race and high genetic variability between populations from different European countries. The regional differences in the intensity of mistletoe occurrence on Scots pines observed in Poland suggest the need to understand the population structure of V. album ssp. austriacum and confirm its taxonomic status.

In a study conducted at the Forest Research Institute, five molecular markers were analysed, including nuclear (ITS1) and chloroplast loci (trnL intron, trnL-trnF IGS, trnH-trnK, ccmp4). The barcode ITS was used in the study because of its broad application in taxonomic analyses. The chloroplast loci, on the other hand, provided the basis for analysing variation among mistletoe populations. For the study, leaves of mistletoe shrubs were collected at sites of the Regional Directorates of State Forests in Wrocław, Gdańsk and Łódź, as well as in Kampinoski National Park. Sequences of 372 bp (ITS1), 541 bp (trnL intron), 303 bp (trnL-trnF IGS), 245 bp (trnH-trnK) and 321 bp (ccmp4) were obtained. The sequences of the ITS1 region, trnL-trnF IGS and trnH-trnK were identical in all specimens examined. Single nucleotide substitutions or deletions were detected in the trnL intron (three specimens) and in ccmp4 (three specimens). Based on the analysis of the ITS1 barcode region and chloroplast loci, the taxonomic affiliation of mistletoe to V. album ssp. austriacum was confirmed. Despite the great geographical diversity of mistletoe populations in Poland, the results confirm the information about the low haplotype diversity in mistletoe from northeastern Europe growing on pine trees.

Keywords: mistletoe; Viscum album; Scots pine; taxonomy; molecular markers

Growth Declines in Scots Pine from Mistletoe Infestation Are Not Caused by Carbon or Water Limitation

Radosław Jagiełło ¹ and Henrik Hartmann ^2,3

¹

Poznań University of Life Sciences, Poznań, Poland

²

Max Planck Institute for Biogeochemistry, Jena, Germany

³

Julius Kühn Institute, Federal Research Centre for Cultivated Plants, Quedlinburg, Germany

*

Correspondence:

Abstract: Infestations of hemiparasitic, xylem-typing pine mistletoe are of great interest because they are rapidly spreading throughout Europe. Droughts, generally considered a major cause of tree mortality, are exacerbated by the additional effects of mistletoe on tree hydraulics and nutrition. Previous studies have not addressed declines in wood production at the stand level. In addition, there is little agreement on the effects of mistletoe on hydraulics and carbon budgets in the central portion of Scots pine’s range. This work is intended to contribute to our knowledge of host plant growth, carbon dynamics and water relations in response to mistletoe infestation. We determined growth dynamics, concentrations of non-structural carbohydrates and carbon isotope ratios (δ13C) in wood of Scots pine (Pinus sylvestris) tree rings as a measure of intrinsic water use efficiency (iWUE).

Material was collected from a mature pine stand in central-western Poland at a mesic site: a pine-dominated boreal forest (EFT). Ten healthy and ten infested trees were randomly selected to represent the full range of breast height diameter. Cross sections were cut at equal 2.6 m intervals along the marketable stem for detailed growth analyses. Log cores were taken at breast height and cut to obtain five-year-old annual wood samples for chemical analyses.

A significant difference in growth was observed between mistletoe-infested and healthy trees with an increasing trend over time. Growth simulations indicated that over the last five years, ten years after mistletoe colonisation, the loss of usable wood yield at the stand level was ~0.85 m³ ha⁻¹ year⁻¹. Significantly higher starch concentrations (0.63 ±0.05 SE mg g⁻¹) were found in the outermost five rings of infested trees compared to healthy trees (0.44 ±0.04 mg g⁻¹). There was a significant increase in iWUE value during the last fifteen years. It increased from 91.5 ± 1.7 SE in 2006–2010 to 94.4 ± 1.6 (2011–2015) and 100.9 ± 1.9 μmol mol⁻¹ (2016–2020). This indicates a general water limitation for pines in the studied region. We did not detect any significant difference in iWUE between healthy and infested trees.

We determined that growth slowdown is a stress indicator of mistletoe infestation. Interestingly, our results suggest that this mistletoe-induced growth reduction can cause a significant loss of wood production, despite the absence of carbon and water limitations. Further research is needed to elucidate the mechanisms leading to tree growth reduction.

Keywords: forest yield; intrinsic water use efficiency; non-structural carbohydrates; Scots pine

Nature Inventory in the Forests of Regional Directorate of State Forests in Krosno (South-Eastern Poland)—Selected Entomological Aspects

Wojciech Grodzki, Marcin Jachym, Mieczysław Kosibowicz and Magdalena Ranocha

Forest Research Institute, Kraków, Poland

*

Correspondence:

Abstract: In the period 2016–2022, in the forests of twenty-six Forest Districts (FD) within the Regional Directorate of State Forests in Krosno (south-eastern Poland), as well as in three adjacent national parks (NP): Bieszczadzki (BPN), Magurski (MPN) and Roztoczański (RPN), an inventory of selected nature elements was performed in order to assess the biodiversity level in managed and protected forest stands. For this purpose, 4680 circular inventory plots were established in regular 1 x 1 km grids. On every second plot (2353 plots), an inventory of selected groups of insects was conducted. Ground beetles were captured using pitfall traps, saproxylic insects: Cucujus cinnaberinus Scopoli and C. haematodes (Erichson), were recorded by the inspection of standing and lying dead trees. We presented selected general results concerning the occurrence of ground beetles belonging to seven species considered as rare, as well as information on the frequency of Cucujus spp. As for the ground beetles (Carabidae): Abax schueppeli rendschmidtii (Germar) was collected in fifteen FDs and two NPs (BPN, MPN); Licinus hoffmannseggii (Panzer)—in twelve FDs and in BPN; Carabus intricatus Linnaeus—in thirteen FDs and two NPs (MPN, RPN); Carabus obsoletus Sturm—in thirteen FDs and in BPN; Carabus scheidleri Panzer—in fifteen FDs and two NPs (BPN, MPN); Carabus irregularis Fabricius—in nine FDs and two NPs (BPN, MPN); Carabus variolosus Fabricius—in sixteen FDs and BPN. Cucujus cinnaberinus and C. haematodes were found in all units. The frequency on the plots in managed forests of twenty-six FDs was 2–57% (23% on average); the frequency on the plots in three national parks was 36–55% (46% on average). Variability of frequency in managed forests was strongly dependent on much higher variability of the stands (especially species composition) in the twenty-six FDs than in the three national parks. Analysis of the data from two FDs at the northern edge of the inventory area revealed that disturbances (in our case—the occurrence of Melolontha spp.) contributed to the enhancement of biodiversity (in our case—of Carabidae); the number of species and biodiversity indices were increasing along with the number of years before the trapping with recorded occurrence of cockchafers. The collected data indicated that a large-area inventory can provide valuable data that contribute to better recognition of the distribution of insects from species considered as rare, and forest management does not negatively affect the insect biodiversity, including the species known to be related to old-growth or primeval forests (Cucujus spp.).

Keywords: insect biodiversity; distribution; ground beetles; Cucujus

What Are the Possibilities of Using Biological Methods in Integrated Management of Forest Insects?

Alicja Sierpińska and Iwona Skrzecz

Forest Research Institute, Sękocin Stary, Poland

*

Correspondence:

Abstract: In Poland, cyclical outbreaks of insects are one of the most important problems of forest protection. Among the most dangerous lepidopterans occurring in pine (Pinus sylvestris) forests are Lymantria monacha, Dendrolimus pini, Panolis flammea and Bupalus piniaria, as well as, where oak (Quercus robur) dominates, Operophtera sp. Unfortunately, the only biological measures currently commercially available are Bacillus thuringiensis subsp. kurstaki (Btk) pesticides for the control of leaf-feeding insects of the order Lepidoptera. Btk insecticides are applied in forests using ULV technology from airplanes or helicopters. In the period 1982–2017, Btk products were used in Polish forest protection on an area of about 630,000 hectares.

There are no biological plant protection products and methods to effectively control root pests of Melolontha spp., foliophagous sawflies (Hymenoptera: Symphyta) or bark beetles, especially Ips typographus. In the past, an inoculative method with Beauveria brongniartii was tested in Poland in reforested areas with a high population density of Melolontha grubs and in forest nurseries: the fungus colonized wheat kernels, which were applicated under the roots of seedlings or on the whole area in nurseries. These trials had very limited positive effects in the control of Melolontha grubs. In Poland, I. typographus continues to be one of the major forestry problems. Laboratory and field tests have been conducted with B. bassiana strains to induce epizootics. While the results of laboratory tests have often been promising, the tested fungal strains have not proved successful under field conditions.

Developing methods to prevent outbreaks and control insect population densities to below harmful levels may be a challenge worth considering. This problem could be solved by taking measures to achieve the stability of the system pest—its natural enemies. Another benefit would be to reduce the use of insecticides in forests. An example of the proposed solution is the introduction of the entomopathogenic fungus Cordyceps militaris by introducing laboratory-infected insects into the forests. Preliminary research by the Forest Research Institute in Poland has shown that it is possible to infect with C. militaris, and consequently, reduce D. pini larvae overwintering in forest litter. The next step will be to support this research with molecular analyses to determine the possibility of persistence of the pathogen in the host population.

Keywords: biological control; Bacillus thuringiensis kurstaki; forest pest insects; entomopathogenes; Cordyceps militaris

New Technologies for Assessing the Effectiveness of Plant Protection Products—Conclusions After the EPPO Workshop

Miłosz Tkaczyk

Forest Research Institute, Sękocin Stary, Poland

*

Correspondence:

Abstract: A workshop entitled “Adoption of Digital Technology for Data Generation for the Efficacy Evaluation of Plant Protection Products” was held in Ede, the Netherlands, from 26–29 June 2022, organised by EPPO (European and Mediterranean Plant Protection Organization) in collaboration with the Netherlands Food and Consumer Product Safety Authority. Seventy-two experts from seventeen EPPO member states attended the meeting. These were representatives from the scientific community, as well as private entrepreneurs. The main objective of the meeting was to familiarize participants with new technologies available on the market and to develop joint conclusions and recommendations for the use of technologies to evaluate the efficacy of plant protection products. The participants were divided into four working groups to discuss the use of digital technologies. Three of them focused on different groups of crop protection products, taking into account the specificities of studies on the efficacy of herbicides, fungicides and insecticides, and the fourth group discussed the use of digital technologies in the context of GEP (Good Experimental Practices) systems. A brief report presented the most interesting of the technologies presented (both those in the research phase and commercially available), as well as summaries and conclusions that could be adopted in the future by EPPO as new standards for evaluating the efficacy of pesticides. The main conclusion of the meeting was that there is currently no need to change EPPO standards due to the use of new technologies.

Keywords: plant protection products; EPPO; GEP; digital technology

Innovative System of Insecticide Application in the Fight Against the Spruce Bark Beetle

Damian Gawron ¹, Tomasz Jabłoński ² and Iwona Skrzecz ²

¹

Silvana Eco Solutions, Warsaw, Poland

²

Forest Research Institute, Sękocin Stary, Poland

*

Correspondence:

Abstract: The spruce bark beetle belongs to a group of insects that have caused considerable damage to forestry in recent years. Spruce trees weakened by lack of water are susceptible to infestation by the bark beetle. The infestation is often gradual and leads to the death of trees in large areas of the forest.

As a result, sanitary cuts must be made, scattered throughout the forest. This leads to a significant increase in the cost of timber harvesting and logging. Another consequence of this situation is the reduction of the quality of the extracted raw material and, consequently, a decrease in the final price of the sold timber.

If we look at the period of the last few years, we notice a significant increase in the harvest of dead wood. It can be assumed that these species “accelerate” the creation of about 1 million m³ of deadwood each year.

Based on the short-term forecast annually prepared by the IBL,…, the amount of populated spruce harvested in recent years was: 2021—0.8 million m³; 2020—1.1 million m³; 2019—1.5 million m³; 2018—1.3 million m³; 2017—1.2 million m³.

The abovementioned problems caused by the bark beetle are not only a problem for the Polish forest industry. A similar problem has occurred in countries where spruce has a significant share in forest stands, e.g., in Switzerland—8 million m³ were harvested between 2000–2009; in Austria—18 million m³ were harvested between 2002–2012.

The methods currently used to limit the damage caused by this species are felling and exporting spruce infested with bark beetles (trees with traps, sawdust trees), burning the parts left behind (branches, bark), spraying the recovered wood with insecticides and setting pheromone traps used only to monitor the development of the population.

Although the biology of the species is known (there have been numerous publications in recent years, such as Spruce Bark Beetle and its Role in Forest Ecosystems, edited by Professor Wojciech Grodzki), it is still impossible to develop effective methods to control this insect.

The damage caused by the bark beetle is a very serious problem in European forestry. So, are foresters doomed to lose the battle against the spruce bark beetle? Not at all. A few years ago, a very efficient and successful method of controlling the spruce bark beetle was developed in the Czech Republic. Thanks to the use of a “working head” that cooperates with an agricultural tractor and a sprayer, it is possible to apply the insecticide on live spruce trees at a height of 12 to 20 m.

Bark beetles attracted by the pheromone die after contact with the insecticide. Contact with the insecticide has a twofold effect: either directly, when the tree is treated, or when the bark beetle tries to enter the tree.

Keywords:Ips typographus; eight-toothed spruce bark beetle; insect pest; control treatment; forest

Actions Taken Against Technical Pests of Oak Tree Beetle—Oak Pinhole Borer—Platypus cylindrus (Fabr.) and Mediterranean Oak Borer—Xyleborus monographus (Fabr.) Bore on in the RDSF in Poznań and Zielona Góra

Hubert Jakoniuk

General Directorate of the State Forests, Forest Protection Unit in Łopuchówko, Poland

*

Correspondence:

Abstract: Unfavorable abiotic and biotic factors leading to the weakening of oak stands in the western part of Poland have resulted in the activation of technical pests—the oak pinhole borer and the Mediterranean oak borer. Until recently, these insects locally occurred or were associated with timber depots and sawmills. Since 2019, there has been a significant increase in the population of these pests, resulting in a reduction in the value of timber in managed forests.

Due to the relative lack of knowledge concerning the biology and management of technical pests, it has been difficult to take appropriate measures to reduce their population and the damage caused. The discrepancy between information in the literature and field observations has led to a series of detailed experiments, the results of which were to be used to develop an appropriate strategy against the pests. The objectives of the experiments included: (1) test the pheromones available on the market; (2) determine the right timing for pest swarms; (3) determine the effectiveness of pest trapping with pheromone traps and classical traps; (4) determine the optimal timing for timber extraction and export.

The trials were conducted in the period 2020–2022 in several forest districts of the Regional Directorate of State Forests in Poznań and Zielona Góra, in whose stands heavy deadwood and infestation of trees by the oak pinhole borer and the Mediterranean oak borer were observed.

Based on two years of research and field inspections, it was possible to increase the knowledge of the necessary elements of pest biology. The results obtained allowed the development of guidelines used to limit the damage caused by engineered pests. The measures against these pests are also included in the new forest protection instruction.

Keywords: oak; technical pests; Platypus cylindrus; Xyleborus monographus

Possibilities of Using Biostimulators in Forestry

Wojciech Pusz ¹, Adrian Łukowski ², Wojciech Kowalkowski ², Piotr Robakowski ², Roman Malik ² and Łukasz Łuczak ³

¹

Wrocław University of Environmental and Life Sciences, Wrocław, Poland

²

Poznań University of Life Sciences, Poznań, Poland

³

Czarne Człuchowskie Forest District, State Forests, Poland

*

Correspondence:

Abstract: One of the main functions of biostimulants is the regeneration of plants after negative stress factors, such as frost, drought and damage caused by improper use of pesticides, as well as regeneration after negative effects of diseases and pests. This effect indirectly consists of stimulating the development of leaves, stems and roots, as well as improving nutrient uptake. Biostimulants are not directly involved in the regulation of physiological processes, but through their effect on metabolism they support and stimulate the life processes of plants. They do this by releasing more energy available in the plant, accelerating the flow of molecules within the cell and between tissues, strengthening cell walls and improving hormone balance in the plant. Biostimulants are usually used for prophylactic or interventional treatments in the form of foliar sprays (medium-drop treatments). However, it has been shown that these substances can also support the action of other chemical compounds due to synergistic effects. To this end, a trial was conducted in the spring of 2021 to determine the possibility of using an L-amino-acid-based biostimulant in the chemical reduction of Prunus serotina. In the trial, herbicides containing the active ingredients glyphosate and a mixture of florasulam and tribenuron-methyl were used as single treatments, and in a mixture with the tested biostimulant. During the two-year study, a significant effect of the mixture of glyphosate and biostimulant on black cherry growth limitation was demonstrated. Another potential use of biostimulants could be to limit disease development by stimulating defense processes in the host plant during infection. To this end, observations were conducted to determine the potential effect of biostimulants on reducing oak powdery mildew (Erysiphe alphitoides). In order to do so, trials with an L-amino-acid-based biostimulant were conducted during the period 2020–2022. The trials were conducted in nurseries with an open and closed root system. The significant effect of the application of the L-amino acid-based biostimulant on the reduction of disease pressure on the part of the oak powdery mildew pathogen was demonstrated. Depending on the dose used, the occurrence of disease symptoms was reduced by 40–60% compared to the control variants. It seems that the use of biostimulants is advisable in different aspects, as well as in different production stages of forest management.

Keywords: biostimulants; Erysiphe alphitoides; plant’s stress; pathogenes; forest

Chemical Treatments and Biodiversity of Microfungi on Pine Crops

Natalia Kartawik, Maciej Hałuszczak, Piotr Łakomy, Joanna Mucha, Radosław Witkowski, Andrzej Mazur and Jolanta Behnke-Borowczyk

Poznań University of Live Sciences, Poznań, Poland

*

Correspondence:

Abstract: Spring pine needle drop is a serious disease that affects the survival and natural regeneration of pines in the early years. It is generally believed to be a factor in natural selection. It is very difficult to reduce the incidence of spring pine needle drop. It is influenced by biotic factors, such as the presence of infectious material, the species diversity of pathogens, the diversity of fungal races and their different pathogenicity, the long duration of infection risk, the high susceptibility of pine to the disease and the needle microbiota. The objective of the study was to determine the taxonomic diversity of fungal communities colonising the needles of Scots pine and their changes in successive experimental years. The experimental plots were established on forest lands where commercial pine stands were removed in the period 2016–2017, and the cleared areas were left to natural regeneration. All conifer communities were strongly dominated by fungi from the Ascomycota group. The next most abundant group was the Basidiomycota. The Mucoromycota group accounted for only a small proportion. The most abundant taxa were: Wynnea americana, Sydowia polyspora, Phaeotheca fissurella, Neocatenulostroma microsporum, Microsphaeropsis olivacea, Meyerozyma guilliermondii, Lophodermium seditiosum, Lophodermium pinastri, Komagataella pastoris, Hypholoma fasciculare, Hypholoma lateritium, Heterotruncatella spartii, Gymnopus androsaceus, Filobasidium wieringae, Didymella macrostoma, Cyclaneusma minus, Ceratocystis pilifera. Considering the great economic importance of Scots pine, the consequences of using chemicals to protect against spring pine needle casting should be studied.

Keywords: pine; needle cast; fungal communities; ITS

Intermediate-Term Forecasting Nun Moth Outbreaks

Lidia Sukovata ¹ and Wiktor Tracz ²

¹

Forest Research Institute, Sękocin Stary, Poland;

²

Warsaw University of Life Sciences, Warsaw, Poland

*

Correspondence:

Abstract: The ability to predict the timing, location and extent of insect pest outbreaks is of great importance for strategic forest management planning. Short-term (up to 1 year) predictions are most common and are based on population densities at the pupal, adult or egg stage. The development of intermediate- (future 1–5 years) and long-term (more than 5 years) prediction models is usually based on historical data, and the longer the time series, the greater the chance of obtaining a good fit of model predictions to empirical data. The nun moth (NM) Lymantria monacha (L.) (Lepidoptera, Erebidae) is one of the most serious pests of Scots pine forests in Poland and its outbreaks usually cover a large area of the country. Data on outbreaks have been collected since the mid-1950s. They include: (a) pest occurrence in year t-1; (b) predicted threat at warning, low, medium and high levels in year t; and (c) pest control with insecticides in year t-1 at the forest district level. The availability of such data provides the basis for developing predictive models, including intermediate-term models. As a first step towards developing comprehensive models for forecasting timing and extent of NM outbreaks, we focused on predicting outbreak onset at the regional level; i.e., for each of the 17 Regional Directorates of State Forests (RDSF) in Poland. This could serve as a warning signal for foresters to pay more attention when assessing insect population density. The onset of an insect outbreak was considered during a year when a medium and/or high threat to forests was first recorded after the previous outbreak. Meteorological conditions were assumed to be among the most important exogenous factors leading to insect outbreaks. Logistic regression was used to analyze the relationships between the onset of the NM outbreaks and 168 meteorological variables with time lags t-2, t-3 and t-4. As a result, 16 logit models were developed for all but one RDSF, where the NM outbreak was never recorded. In the next step, we focused on developing models using Random Forest to predict the onset of outbreaks at the level of groups of forest districts formed by considering their proximity to the nearest meteorological station and the similarity of NM outbreak history. The results of intermediate-term predictions at different levels were compared with the short-term predictions (less than 1 year) made by foresters according to standard protocols.

Keywords:Lymantria monacha; Lepidoptera; outbreak predictions; logistic and random forest models; meteorological data

Flight Dynamics of Great Pine Web-Spinning Pine Sawfly  Acantholyda posticalis (MATS.) Using Traps in Three Regions of Increased Occurrence

Tomasz Mokrzycki

Warsaw University of Life Sciences, Warsaw, Poland

*

Correspondence:

Abstract:Acantholyda posticalis in Poland is classified as a dangerous, primary pest of Pinus sylvestris. Monitoring its population is of great importance for making decisions about controlling this insect and protecting forest stands.

The aim of the study was to investigate the influence of air temperature on the flight dynamics of Acantholyda posticalis and the influence of the location of the trap on the accuracy of monitoring. The effect of population location on insect size was also studied.

Observations of Acantholyda posticalis were carried out in 2020 and 2021 from mid-March to the end of August in the following Kolumna, Lubliniec and Przedborów forest districts. On each plot, 12 “Geolas” traps were placed on pine trees. Three loggers were placed on each research plot to measure air temperature. The body length of 80 randomly selected males and females was measured from each forest district.

In 2020, in the Kolumna forest district, the culmination of the flight of females occurred between 8–12 April, and a year later on 20 April. In 2020, in the Lubliniec forest district, the culmination of the flight of females occurred on 20 April, and a year later on 24 April. In 2020, in the Przedborów forest district, the culmination of the flight of females occurred on 18 April, and a year later on 22 April.

In all forest districts, the temperature had a noticeable effect on the number of males and females in the initial period, up to flight culmination.

Compared to 2020, a later appearance of the Acantholyda posticalis and a clearly shorter period of activity, as well as the subsequent culmination of the flight, were observed. In order to check whether the air temperature in both years could have had an impact on the flight dynamics, the significance of the differences during the period from 20 March to 30 April was checked. In the Kolumna and Lubliniec forest districts, the temperatures in 2021 were lower than the temperatures recorded in 2020, and these differences turned out to be statistically significant. In the Przedborów forest district, these differences were insignificant.

Research on the influence of tree location in the stand on the number of Acantholyda posticalis showed no statistically significant differences. The location of the tree with the trap did not significantly affect the accuracy of the monitoring.

In the Lubliniec forest district, males and females were significantly smaller than in other forest districts.

Keywords:Acantholyda posticalis; flight dynamics; air temperature; monitoring

Amount and Dynamics of the Foliage Consumption Caused by Great Web-Spinning Sawfly Acantholyda posticalis  (Mats.)

Marek Sławski and Małgorzata Sławska

Warsaw University of Life Sciences, Warsaw, Poland

*

Correspondence:

Abstract: Under field conditions, measurement of the amount of foliage eaten by primary pests faces some methodological difficulties. In forestry practice, it is often limited to estimation of the foliage loss as a percentage compared to healthy stands. The research presented is an attempt to determine the magnitude of needle consumption caused by the Acantolyda posticalis based on the weight of frass drop on the forest floor. The weight of collected feces was converted to consumption based on a laboratory-determined factor. The conversion factor was determined based on the rearing of larvae fed with a known weight of needles and measurement of the excrements produced. The average conversion factor was 1.32 (±0.02), which means that 1 g of frass represents 1.32 g of needles eaten. Additionally, the correction factor for the loss of fecal weight due to leaching by precipitation was determined to be 1.23. Frass traps were placed in four outbreak and four control stands, with six traps in each stand. The traps were emptied every week during the feeding activity of A. posticalis, i.e., from the beginning of May to the end of July in 2021 and 2022. The frass was sorted, dried and weighed, and then consumption was calculated. The average level of needle consumption in the outbreak stands reached 745 kg/ha, while in the control plots it was 70 kg/ha. Consumption in 2021 was twofold greater than in 2022, with 678 kg/ha and 304 kg/ha needles eaten, respectively. The highest consumption in both years studied was measured in the two first weeks of June in both years. The studies allowed us to find differences between the consumption levels of the studied stands. The highest level of consumption in the outbreak stands amounted to 1300 kg/ha, while the lowest was 500 kg/ha. In the control stands, the highest consumption amount was about 100 kg/ha and the lowest was 50 kg/ha. The method used was relatively simple and allowed us to objectively estimate pest consumption in the canopy of pine stands. The proposed method makes it possible to measure pest pressures in successive years and control the dynamics of the outbreak, as well as to determine the spatial variation of damages caused by pests in specific forest complexes, and track the dynamics of feeding during the growing season.

Keywords: frass drop; primary pest; pine stand

Western Conifer Seed Bug (Leptoglossus occidentalis (Heidemann, 1910)) (Insecta: Hemiptera: Coreidae)—As a Potential Pest in Forest Management

Dawid Marczak

University of Ecology and Management in Warsaw, Poland

*

Correspondence:

Abstract: The western conifer seed bug (Leptopglossus occidentalis) belongs to the leaf-footed bugs (Coreidae) within Heteroptera. Its original range is North America, where it occurs in Mexico, the western parts of the United States and southern Canada. It was introduced to Europe in the late 20th Century, and the first reports were from Italy. In subsequent years, it colonised southern, central and western Europe. Outside Europe, the species is also native to Asia, and has been reported in Turkey, Israel, Georgia, Kazakhstan and the Far East, in China, Korea and Japan. In recent years, it has also been reported in Africa: Tunisia and Morocco. It has been known in Poland since 2008. Leptoglossus occidentalis is an oligophagous species that develops on various coniferous species, where it feeds on the sap of young cones. The cones pierced by this hemipteran deform and do not form seeds. In its natural range in North America, this species is considered a pest in conifer plantations, where it can damage up to 80% of the seeds of Pinus monticola. In Europe, it damages pine crops by reducing the seed production of Pinus pinea. In California, it has also been found to be a pest of Pistacia vera. The species has also been reported in California on Amygdalus communis, and from Spain on Pistacia lentiscus. The insect overwinters as an imago hidden under loose bark, in tree cavities or crevices. Interestingly, this hemipteran easily winters in nature, as evidenced by the finding of a live adult individual in March under the bark of a Pinus sylvestris. It can also overwinter in human households, where its large aggregations can be quite a nuisance. The species has quickly established itself in new areas, as it is usually transferred with the plants between plantations and seedling distributors. In addition, the well-developed wings of the adults allow them to easily move about their location and expand their range to where they have been brought.

Keywords: pest insects; Hemiptera; Leptoglossus occidentalis; cones pest; forest protected

Evaluation of the Biological Activity of Mospilan 20 SP and Dimilin 480 SC in Reducing the Abundance of the Eastern Saw Bush-Cricket (Barbitistes constrictus Br.) in Pine Stands

Artur Rutkiewicz and Iwona Skrzecz

Forest Research Institute, Sękocin Stary, Poland

*

Correspondence:

Abstract: In Polish forests, the eastern saw bush-cricket is one of the insects that causes great economic damage in pine stands. The largest area of occurrence and control of Eastern Saw Bush-cricket was shown in the 1960s. The area of occurrence then reached a total of 20.5 thousand hectares. Considering the constant intensive damage caused by this species and the decreasing number of possible insecticides, an attempt was made to evaluate the biological activity of two preparations used in Polish forests. The evaluation of biological activity of preparations Mospilan 20SP and Dimilin 480SC to reduce the number of Barbitistes constrictus was carried out by the Regional Directorate of State Forests in Toruń. The trial was conducted in 40–50-year-old Pinus sylvestris pine stands, where an intensive occurrence of pine pollen was found, with up to 1000 individuals per tree. Two variants of the experiment were conducted, in which Mospilan 20SP was applied at a dose of 0.3 kg or 0.4 kg mixed with 1 L of Ikar 95EC adjuvant and 2 L of water per 1 ha of pine stand. In the trials with Dimilin 480SC, 0.1 L of the preparation and 7 L of Ikar 95EC adjuvant and 2.2 L of water per 1 ha were used. In the experimental treatment, pine stands were sprayed by a Dromader M18 aircraft equipped with AU 5000 atomizers. The control of the experiment was unsprayed stands. After the pest control treatment, the fall of live and dead woodworms from the canopies was monitored every day for five days. Three weeks after treatment, the control trees were felled and the number of live and dead insects in the crowns was counted. Based on the results of the insect fall and the number of opiates found in the crowns of the control trees, pest mortality in the plots of the treatment variants and in the control was calculated as a percentage. The results of the experimental treatment with Mospilan 20 SP at doses of 0.3 and 0.4 kg/ha showed a mortality of no more than 30% of the individuals feeding in the crowns of the trees within three weeks after treatment. These results indicate low efficacy of the insecticide used to protect the forest against Barbitistes constrictus. In the stands sprayed with Dimilin 480SC, it was 93.2%.

Keywords:Barbitistes constrictus; pest insects; Mospilan; Dimilin

Great Capricorn Beetle (Cerambyx cerdo Linnaeus, 1758) in the Odra Valley—Species Protection and Forest Management

Andrzej Mazur ¹, Jarosław Góral ², Katarzyna Nowik ², Katarzyna Skałecka ², Grzegorz Rogowski ² and Radosław Witkowski ¹

¹

Poznan University of Life Sciences, Poznań, Poland

²

General Directorate of the State Forests, Forest Protection Unit in Wrocław, Poland

*

Correspondence:

Abstract: The great capricorn beetle is one of the largest beetles developing in the wood of oaks and other deciduous trees. In Poland, the species locally occurs, and its typical biotope are stands of river valleys, with the share of old oaks growing in exposed positions. The species also inhabits trees in parks, alleys and dikes. Since 1952, the great capricorn has been a subject of legal protection in Poland (it is also protected under the EU Habitats Directive 92/43/EEC). One of the most frequently described conflict situations is the presence of the great capricorn beetle on monumental trees, which are also subject to legal protection. In the forest of the Regional Directorate of State Forests in Wrocław, located in the Odra valley, in recent years, an increase in the population of the great capricorn beetle has been observed, which results in the colonization of trees of high economic value in managed stands. The presentation describes the spread of the species in the natural environment and the conflict between species conservation and wood production, especially where the great capricorn beetle is abundant. In managed forests, no inventory of new occurrence sites of the species has been made, and population size is not monitored. On the other hand, trees inhabited by Cerambyx cerdo, with clear symptoms of its presence, due to the strict legal protection of the species, cannot be cut down.

On the basis of available data on the biology and ecology of the species, factors potentially influencing the success of the great capricorn beetle populations were discussed: the impact of high temperatures (observed since 2015); drought resulting in the decreased condition of trees (groundwater level decrease, even in river valleys); the age and structure of forest stands (over 11,000 ha of oak stands over 140 years old), as well as little or no pressure from forest management. Suggestions for economic, protective and compensatory measures in managed stands with the great capricorn beetle population were presented.

Keywords:Cerambycidae; protection of insect species; river valley; oaks stands

Occurrence of Blastobasis glandulella (Riley, 1871) (Lepidoptera: Blastobasidae) on Sessile Oak Seed Plantations in the RDSF in Zielona Góra (Poland)

Cezary Bystrowski ¹ and Hubert Jakoniuk ²

¹

Forest Research Institute, Sękocin Stary, Poland.

²

General Directorate of the State Forests, Forest Protection Unit in Łopuchówko, Poland

Abstract: In the period 2021–2022, on two sessile oak seed plantations in the Forest Districts of Świebodzin [N 52°08′19″ E 15°21′40″] and Krzystkowice [N 51°42′56.0″ E 15°13′29.0″] (RDSF Zielona Góra) monitoring of acorn phytophages of hatching was carried out using tent traps. The traps used were photoelectrators with a catch-controlled area of about 2 m² each. In both seed orchards, 10 such traps were randomly placed under the crowns of fruiting oaks. Insects leaving soil under the tents were trapped in white plastic bottles half filled with glycol, into which they fell, naturally striving for the light. The bottles were inspected and caught insects were collected, from mid-May to the end of August, once a week. During the study, numerous populations of the butterfly Blastobasis glandulella (Riley, 1871) (Lepidoptera: Blastobasidae) were found on both plantations. This species comes to Europa from North America, where they mainly occur in the USA and southern Canada. B. glandulella was found in Europe in the 1980s and described as Blastobasis huemeri Sinev in 1993. Landry et al. (2013:26) stated that the populations from Europe are identical to the American species B. glandulella described from the state of Missouri (USA) in the 19th Century. White caterpillars of this species with characteristic delicate symmetrical puncturing of their body overwinter inside acorns on soil in the oak stand. Under the conditions of the tested seed orchards from RDSF Zielona Góra in 2021, the hatching of specimens began in end of May and lasted until the first days of September (3.09). However, the most numerous of the species hatched in the second half of June and July. Their appearance was extended without a clear culmination. In total, throughout the season, the traps caught: in the Świebodzin Forest Inspectorate—229 individuals (average—11.5 individuals/m²); and in the Forest Inspectorate Krzystkowice—459 individuals (23 people/m²). In 2022, there was a decrease in the number of caught B. glandulella butterflies. Using the same methodology, the following were caught: in the Świebodzin Forest Inspectorate—65 individuals (average—3.1 individuals/m²); and in the Krzystkowice Forest Inspectorate—151 individuals (7.6 people/m²). This was most likely the result of insecticide treatment of the species population in 2021. The plantation in the Świebodzin Forest Inspectorate was experimentally treated twice (on 19 July 2021 and 10 August 2021) with Coregan 200 SC (the active substance Chlorantraniliprole) at a dose of 175 mL/ha, and the plantation in Forest District Krzystkowice with Mospilan 20SP (active substance acetamiprid) at a dose of 0.2 kg/ha.

B. glandulella bears all the hallmarks of an invasive species, and it seems that the registration of effective insecticides, thanks to which it will be possible to control its numbers, will allow a satisfactory yield of acorns for the needs of forest management in the future.

2. Concluding Remarks

The weakening of coniferous and hardwood stands due to worsening drought since 2015 has led to problems with secondary pests and pathogenic fungi, and the decline in soil moisture has negatively affected the function of ectomycorrhizal fungi.

As a result of climate warming, the probability of invasive occurrences of new insect and fungal species, typical of areas with higher air temperatures, is increasing in Poland.

Constant monitoring of the occurrence of these organisms is necessary, especially in nurseries and stands near border crossings and ports.

Due to climate change, the occurrence of new insect species and tree diseases in Poland is gaining economic importance.

The occurrence of hemiparasites on trees (Loranthus europaeus and Viscum album ssp. austriacum) and their negative impact on the health of host plants is increasing.

Opportunities are being sought to use both innovative chemical and non-chemical methods in modern forest protection against fungal diseases and insects; e.g., a detector system for monitoring pine pests in forest plantations.

The resistance of ash trees to fungal diseases, especially Hymenocyphus fraxineus, needs to be researched.

Monitoring of selected elements of pine production in container nurseries will enable the production of high quality planting material.

Models should be developed to predict the spread of nun (Lymantria monacha) in the medium term, as well as issues related to monitoring Acantolyda posticalis.