Pine Looper Research Articles

On the Weather Factors which Cause Outbreaks of Foliophagous Insects (on the Example of Black-veined White Aporia crataegi (L.) (Lepidoptera, Pieridae) in the Urals

On the example of the outbreak foci of black-veined white, that sprung up in the Urals in 2020, is shown how outbreak foci of the pest begin to develop. Besides in the article for the fi rst time the method of quantitative assessment of average span time during which occur formation of the outbreak foci of black-veined white and pine looper Bupalus piniarius (L.) is described. It is shown that outbreak foci of the both species come into being during interval of time no more than 1 hour. Average data of the black-veined white and pine looper outbreak foci formation in the south of Sverdlovsk region are 13 and 14 June accordingly.

Autoregression, First Order Phase Transition, and Stochastic Resonance: A Comparison of Three Models for Forest Insect Outbreaks

Three models of abundance dynamics for forest insects that depict the development of outbreak populations were analyzed. We studied populations of the Siberian silkmoth Dendrolimus sibiricus Tschetv. in Siberia and the Far East of Russia, as well as a population of the pine looper Bupalus piniarius L. in Thuringia, Germany. The first model (autoregression) characterizes the mechanism where current population density is dependent on population densities in previous k years. The second model considers an outbreak as analogous to a first-order phase transition in physical systems and characterizes the outbreak as a transition through a potential barrier from a low-density state to a high-density state. The third model treats an outbreak as an effect of stochastic resonance influenced by a cyclical factor such as solar activity and the “noise” of weather parameters. The discussion focuses on the prediction effectiveness of abundance dynamics and outbreak development for each model.

Differentiation of Forest Stands by Susceptibility to Folivores: A Retrospective Analysis of Time Series of Annual Tree Rings with Application of the Fluctuation-Dissipation Theorem

This study analyzed the relationship between characteristics of annual tree ring time series and the intensity of attacks on forest stands by forest insects. Using tenets of the fluctuation–dissipation theorem (which is widely used in physics), time series parameters are proposed that can help to assess the susceptibility of a forest stand to insect pests. The proposed approach was applied to evaluate differences in parameters of tree ring widths among outbreaks of the pine looper, Siberian silk moth, and spongy moth. A comparison of trees characteristics between outbreak locations and undamaged forest stands (control) showed that the tested parameters statistically significantly differed between the outbreak locations and control stands and can be used to assess the risk of pest outbreaks in forest stands.

Mass Reproduction Outbreaks of the Phyllophagous Insects in Forests of the North-West of the European Part of Russia

Data on the species composition and dynamics of outbreaks of needle- and leaf-eating pests that pose a danger to forest stands in the Arkhangelsk, Leningrad and Murmansk regions,as well as in the Republics of Karelia and Komi were summarized and analyzed. A significant decrease in the frequency of reproduction outbreaks of certain types of needle- and leaf-eating pests was shown, which corresponds to the trends for some other regions. For the pine looper (Bupalus piniaria (L.)), the pine beauty (Pannolis flammea), the buff-tip (Phalera bucephala (L.)), the rusty tussock moth (Orgyia antiqua (L.)) and the white satin moth (Leucoma salicis (L.)), who have had a few mass reproduction outbreaks in the aforementioned regions, no significant increase in population density was observed for 25 years or more. An increase in outbreak activity and expansion of the damage area to the north is likely for the winter moth (Operophtera brumata (L.)) and the autumnal moth (Epirrita autumnata). The larch tortrix (Zeiraphera griseana) and the spruce sawfly (Gilpinia hercynia) are in the list of potential dangers as well. These species have only one, but an extremely extensive reproduction outbreak. The red pine sawfly (Neodiprion sertifer Geoffr.) and possibly the common pine sawfly (Diprion pini (L.)) will continue to play a significant role as pests of young stands. The dynamics of their outbreaks, apparently, is determined by climatic changes and, to no lesser extent, by the presence of large areas of conifers’ regeneration. An increase in the fluctuations’ amplitude of the pests populations’ density in urban plantations is likely to occur, especially the miner moths (Phyllonorycter isskii, Ph. populifoliella and Ph. apparella), for which the current climate warming is a fundamentally important factor.

Current State of Pineries in Zhytomyr Polissia Under the Influence of Environmental Factors

Recently, there has been a massive drying of conifers all over the world. In North America and Siberia, there are millions of hectares of shrunken plantings; in Europe, pines and firs have been drying up over the past two decades. Furthermore, considerable damage is caused to woody plants by phyto-pest and phyto-diseases, since mass reproduction of Ips typographus Linnaeus, Ips acuminatus Gyllenhal has been observed in Europe in recent years, Dendroctonus micans Kud – in North America, Polygraphus proximus Blandford – in East Asia. Nematodes also cause significant damage to pine forests. Among phyto-diseases, Heterobasidion annosum (Fr.) Bref. harmfully affects Pinus sylvestris L. The appearance of foci of shrunken trees in different parts of the globe indicates the global nature of processes associated with cyclical planetary processes and climate change. This study describes climate changes in the research region for 1961-2020. According to the analysis, it was found that for 2009-2020, considerable damage to pine plantations in Zhytomyr Polissia is caused among needle-eating insects – Panolis flammea Denis & Schiffermuller, Diprion pini L., Neodiprion sertifer Geoffroy; among other pests – Aradus cinnamomeus Panz, Dendrolimus pini L., Bupalus piniarius L. The greatest harmful effect that pineries have recently sustained has been caused by Diprion pini L. It was also found out that among phyto-diseases suffered by the pine forests, significant damage has been done by Heterobasidion annosum (Fr.) Bref., with the damaged area of 13.0-14.2 thousand hectares. Hydrothermal analysis was performed for 2009-2020. The influence of solar activity on the number of phyto-pest and diseases is analysed. This paper provides the estimate of the amount of CO2 emissions is given for 2009-2020. It was found that since 2014, the amount of carbon dioxide emissions has decreased from 1.5 million tonnes to 0.6 million tonnes. Correlation analysis of all indicators indicated a high mutual influence between the area of trees damaged by insect pest, root sponge, the Wolf number, and CO2 emissions to the environment. Mathematical dependences are obtained to predict the influence of the W number on damage to pineries by forest pests and diseases in the conditions of Zhytomyr Polissia

Influence of Weather Conditions and Climate Oscillations on the Pine Looper Bupalus piniaria (L.) Outbreaks in the Forest-Steppe of the West Siberian Plain

The pine looper Bupalus piniaria (L.) is one of the most common pests feeding on the Scots pine Pinus sylvestris L. Pine looper outbreaks show a feature of periodicity and have significant ecological and economic impacts. Climate and weather factors play an important role in pine looper outbreak occurrence. We tried to determine what weather conditions precede B. piniaria outbreaks in the southeast of the West Siberian Plain and what climate oscillations cause them. Due to the insufficient duration and incompleteness of documented observations on outbreaks, we used the history of pine looper outbreaks reconstructed using dendrochronological data. Using logistic regression, we found that the factor influencing an outbreak the most is the weather four years before it. A combination of warm spring, dry summer, and cool autumn triggers population growth. Summer weather two years before an outbreak is also critical: humidity higher than the average annual value in summer is favorable for the pine looper. The logistic regression model predicted six out of seven outbreaks that occurred during the period for which weather data are available. We discovered a link between outbreaks and climatic oscillations (mainly for the North Atlantic oscillation, Pacific/North America index, East Atlantic/Western Russia, West Pacific, and Scandinavian patterns). However, outbreak predictions based on the teleconnection patterns turned out to be unreliable. We believe that the complexity of the interaction between large-scale atmospheric processes makes the direct influence of individual oscillations on weather conditions relatively small. Furthermore, climate changes in recent decades modulated atmospheric processes changing the pattern predicting pine looper outbreaks: Autumn became warmer four years before an outbreak, and summer two years before became drier.

Trends in Outbreaks of Defoliating Insects Highlight Growing Threats for Central European Forests, and Implications for Eastern Baltic Region

To identify general patterns in the effect of climate-driven changes in the outbreak frequency of forest defoliating species, we examined 60 years of records (1950–2010) of outbreaks of five defoliating species. Data on Lymantria dispar, Lymantria monacha, Bupalus piniarius, Panolis flammea, and Operophtera brumata from five Central European countries (Slovakia, Czech Republic, Austria, Hungary, and Germany), where the current climate is comparable with the projections of climate for the Eastern Baltic region by the end of the 21st century, were analyzed. Time series approach was applied to estimate the linkage between outbreaks and climate warming. Mean annual, summer, and winter deviations for the period of 1850 to 1900 were assessed as proxies of warming. To estimate the legacy effect, warming proxies were lagged by one year. Among those tested, warming proxies showed a linkage with outbreaks. Three significant outbreaks occurred in the analyzed period (at the beginning and end of the period). During the middle part of the analyzed period, the frequency and magnitude of outbreaks were low, implicating a higher insect outbreak risk with warming in Central Europe. In the latter part of the analyzed period, more frequent yet smaller outbreaks occurred, which supports the outbreak linkage with one-year lag, summer, and annual temperatures.

Pine Looper Bupalus piniaria (L.) Outbreaks Reconstruction: A Case Study for Southern Siberia.

Simple SummaryThe pine looper damages Scots pine forests over vast areas. However, the study of its population fluctuations is hampered by the lack of long-term observation series. The dendrochronological reconstruction is often used to study the history of its outbreaks. In some cases, such reconstructions require methods that work without comparison with other tree species. We have proposed such a technique based on the analysis of the early- and latewood growth. The technique makes it possible to separate the effect of defoliation on tree rings from weather influence. Besides, it is more sensitive than previously developed methods when reconstructing outbreaks of the pine looper. The history of outbreaks reconstructed by the technique for the West Siberian Plain’s forest-steppe includes 11 defoliation events from 1914 to 2017. The results obtained using the developed method are useful to better understand the patterns of population dynamics of the pine looper and other phyllophagous pests.The pine looper Bupalus piniaria is one of the most widespread phyllophagous insect species across Northern Eurasia, defoliating Scots pine forests over vast territories. Since there are not enough long-term documented observations on a series of outbreaks, there is a need for methods allowing them to be reconstructed to study their dynamics patterns. Previously, dendrochronological methods were successfully used to solve such issues. However, the most common approach is not applicable for the Western Siberian forest-steppe since it requires comparison with a non-damaged tree species close to pine in terms of longevity and resistance to rot. In the pine forests of the steppe and forest-steppe zones of Western Siberia, there are no species that are not damaged by the pine looper that meets these requirements. Methods allowing not using control species are also not free from disadvantages (e.g., weak specificity). Therefore, we have developed a new method based on the analysis, not of the tree-ring width but the early- and latewood width to reconstruct past defoliation events. The past defoliation by the pine looper is indicated by the presence of a negative pointer year for latewood, followed by a negative pointer year for earlywood in a subsequent year among the majority of individuals. Linear modeling showed a difference between the climate impact on radial growth and the defoliation one. The obtained reconstruction was compared with the results of other methods (mowing window, OUTBREAK, independent component analysis), literature, and Forest Service data. The developed new method (pointer year method; PYM) showed high efficiency confirmed by results of the tree-ring series analysis (11 revealed outbreaks in the past). Compared with other reconstruction techniques under the given conditions (a favorable combination of heat and humidity; probably low-intense and short defoliation), the proposed method provided more precise results than those proposed earlier. Due to high accuracy, the PYM can be useful for detecting late-summer and autumn past defoliations of tree species with clear difference between early- and latewood even though the damage was weak.

The Effect of a Pine Looper Moth Outbreak on the Radial Growth Rate of Pine

This study compares the 1945–2015 time series of the radial growth rate of pine Pinus sylvestris L. damaged by the 1974–1978 outbreak of the pine looper moth Bupalus piniarius L. and those of the undisturbed Krasnoturansk pine forest. It is proposed to employ regulatory characteristics of time series, including the order of autoregression (lag value n) and standard deviation of the amplitude of time series oscillation s (number of the first differences of radial growth s), to estimate differences between radial growth rates of trees in damaged and intact stands. These indicators allow for a quantitative assessment of the lag of the processes regulating the radial growth rate. Only the first differences of the series of radial growth rate are assessed, inasmuch as the regulatory characteristics can be correctly calculated only for the stationery time series. Trees exposed to insect outbreak either have no lag in the dynamics of the first differences of the series in the radial growth rate or they have high values of autoregression order n. At the same time, the oscillations of the current radial growth rate of damaged trees in relation to the age gradient are significantly larger than in undisturbed trees. We estimate the speed of the growth-rate recovery in damaged trees as a function of regulatory characteristics of time series of the radial growth rate before the damage. These data could be used to assess the pest hazard in the stands and recovery rates of forests damaged by insect outbreaks.

Differences in the Dynamics of Radial Tree Increment in the Pine Looper Outbreak Area and in Undamaged Stands and Assessment of the Risk of Pests’ Attack

The time series of the radial increment of pine Pinus sylvestris L. in 1945–2015 were studied on the territory of the Krasnoturansky pine forest in the stands damaged during the outbreak of the pine looper Bupalus piniarius L. in 1974–1978 and in the stands not damaged by the pest. To assess the differences in the processes of radial increment of trees in damaged and undamaged stands before the outbreak, it is proposed to use the regulatory characteristics of time series, such as the values ​​of n delay (autocorrelation) and the amplitude s of fluctuations in time series. According to these indicators, one can numerically assess the inertia of the processes of regulation of radial increment. Since the regulatory characteristics can only be correctly calculated for stationary time series, the series of the first differences of the radial increment were used for the calculations. The trees in the stands that were attacked by insects were characterized either by the absence of delay in the time series, or by sufficiently large values ​​of the order of autocorrelation (n). Moreover, fluctuations in the current radial increment relative to the age trend were significantly greater in trees in damaged stands than in undamaged ones. The rate of growth recovery in trees damaged by insects depending on the regulatory characteristics of the time series of radial increment before the onset of damage was assessed. The obtained characteristics can be used to assess the risk of phyllophages’ attacks on stands and the rate of restoration of stands damaged by insects.

Phytophage–entomophage interactions at different stages of mass reproduction of forest insects

A model that implies highly inertial regulation of phytophage numbers by entomophages has been applied for the analysis of phytophage–entomophage interactions during different phases of the gradation cycle of phyllophagous insects. The data on population dynamics and the degree of parasite infestation in pupae of the pine looper Bupalus piniarius L. and fir looper Ectropis (=Boarmia) bistortata Gz are used to verify the model. The results of field studies apparently are in good agreement with the model of highly inertial regulation in the “phytophage–entomophage” system. The model that is proposed explains the decisive roles of different factors (entomophages, predators, or diseases) in the population dynamics of phytophages under different conditions.

Population dynamics and stability of forest insects with low density (using the example of populations of the bordered white Bupalus piniarius L.)

The abundance dynamics of different populations with the bordered white Bupalus piniarius L. has been analyzed. It has been demonstrated that the populations of B. piniarius in different habitats at the territory of Europe and the Asian part of Russia have cyclic oscillations in their density when in a stable-sparse state. A mathematical model describing regulatory processes in the population of B. piniarius in a stable-sparse state has been proposed.

Forest defoliator outbreaks under climate change: effects on the frequency and severity of outbreaks of five pine insect pests

To identify general patterns in the effects of climate change on the outbreak dynamics of forest-defoliating insect species, we examined a 212-year record (1800-2011) of outbreaks of five pine-defoliating species (Bupalus piniarius, Panolis flammea, Lymantria monacha, Dendrolimus pini, and Diprion pini) in Bavaria, Germany for the evidence of climate-driven changes in the severity, cyclicity, and frequency of outbreaks. We also accounted for historical changes in forestry practices and examined effects of past insecticide use to suppress outbreaks. Analysis of relationships between severity or occurrence of outbreaks and detrended measures of temperature and precipitation revealed a mixture of positive and negative relationships between temperature and outbreak activity. Two moth species (P.flammea and Dendrolimus pini) exhibited lower outbreak activity following years or decades of unusually warm temperatures, whereas a sawfly (Diprion pini), for which voltinism is influenced by temperature, displayed increased outbreak occurrence in years of high summer temperatures. We detected only one apparent effect of precipitation, which showed Dendrolimus pini outbreaks tending to follow drought. Wavelet analysis of outbreak time series suggested climate change may be associated with collapse of L.monacha and Dendrolimus pini outbreak cycles (loss of cyclicity and discontinuation of outbreaks, respectively), but high-frequency cycles for B.piniarius and P.flammea in the late 1900s. Regional outbreak severity was generally not related to past suppression efforts (area treated with insecticides). Recent shifts in forestry practices affecting tree species composition roughly coincided with high-frequency outbreak cycles in B.piniarius and P.flammea but are unlikely to explain the detected relationships between climate and outbreak severity or collapses of outbreak cycles. Our results highlight both individualistic responses of different pine-defoliating species to climate changes and some patterns that are consistent across defoliator species in this and other forest systems, including collapsing of population cycles.

Temporal variability in model coefficients: Bupalus piniarius as a case study

Given a population dynamics model and a sufficiently long time series of data, the model parameters can be measured in different segments of this series to get respectively different estimates and a model with time-variable parameters. The variations in model parameters can be caused either by variations in the environmental conditions which affect population size, or by mere demographic stochasticity. As an example, a possible approach to the issue is considered for the data on fluctuations in the population density of pine moth (Bupalus piniarius L.) in Germany. To approximate the data, the well-known Moran-Ricker model is used, which has a rich variety of dynamic regimes. Parameter estimation was carried out by the least squares method (along 12 out of 58 values). The analysis of trends in the two series of model coefficients--the maximal growth rate and the coefficient of self-regulation--reveals that the changes in both indexes are low for quite a long period of time (60 years), and the hypothesis of no directed trends in the environment changes turns out statistically plausible.

Pine defoliator Bupalus piniaria (L.) (Lepidoptera: Geometridae) and its entomopathogenic fungi. 2. Pathogenicity of Beauveria bassiana, Metarhizium anisopliae and Isaria farinosa

Fungi Beauveria bassiana, Metarhizium anisopliae and Isaria farinosa (local strains), were tested on 3rd and 4th instar larvae of pine defoliator Bordered White moth (Pine Looper), Bupalus piniaria (L.) (Lepidoptera: Geometridae) under laboratory conditions. Reared larvae were sprayed with the fungal suspension at a concentration of 1 × 108 conidia mL–1. All three fungi species tested increased mortality of larvae as compared to control (distilled water spray). The highest (100%) mortality was caused by B. bassiana within 12 days, followed by M. anisopliae: 18 days were needed to reach the same mortality level. The lowest mortality was caused by I. farinosa: even double spray resulted only in 56.67 ± 6.6% mortality. The most effective entomopathogene was B. bassiana. Keywords: biological control, Bordered White (Pine Looper), Bupalus piniaria (L.), forest pests, insect pathogens, mortality, microscopic fungi

A variogram-based analysis of insect wing images to detect outbreaks: a case study of a pine looper (Bupalus piniarius L.) population

The coloration of forest insects changes as their population density increases or decreases. Using the geostatistical method allowed us to determine the population dynamics’ phase of the pine looper from images of insects’ wings. The color and pattern of the insects’ wings can be successfully used as diagnostic features in determining the phase of the population dynamics.

Pine defoliator <i>Bupalus piniaria</i> L. (Lepidoptera: Geometridae) and its entomopathogenic fungi: 1. Fungi isolation and testing on larvae

Pine defoliator <i>Bupalus piniaria</i> L. (Lepidoptera: Geometridae) and its entomopathogenic fungi: 1. Fungi isolation and testing on larvae

Die morphologischen Merkmale und die Bionomie der Kiefernspanner-Tachine Carcelia obesa Zett. (=rutilla B. B.)

1 The Tachinid Carcelia obesa Zett. (= rutilla B. B.) is in Holland an important parasite of the pine looper (Bupalus piniarius L.), a pine wood inhabiting geometrid moth. 2 As an introduction to future papers on the function of the parasitic fly as a mortality factor to the moth, the most important data on its external morphology and life history are represented here. 3 The most important characteristics of the adult fly can be found by Baer (1920/1921). See also fig. 1. The female parasite bears on her relatively broad forehead two large hairs curved downwards, which are lacking in the male. 4 The egg has the macrotype form (Clausen 1940) with its ventral surface flat and the chorion thin and transparent. Its surface bears rather minute reticulate markings. 5 The most important characteristics of the three larval instars have been described (fig. 2, 3, 4 and 5). 6 The puparium is of the general subelliptical form. The anal opening and the anterior and posterior spiracles are distinct. Prothoracic cornicles are present. There are two lines of cleavage. 7 The adult fly emerges from the puparium in June—July; the males 6 days before the females in average. Mating normaly takes place very soon after emergence. 8 After mating the fertilized eggs descend into the uterus where incubation takes place over a period of three weeks in average. Then the larvae can be observed through the transparent egg chorion. 9 The incubated eggs are deposited on the skin of the caterpillers, which at the time are in the second and third instar. There within 2–24 hours the larva bores directly downward through chorion on the vertral side of the egg and through the integument of the host body. Most often the young larvae enter the wall of the foremost part of the intestine; afterwards they enter a muscle. They have a cutaneous respiration. 10 Hibernation takes place in the host puparium without apparent growth. The latter begins at the end of March and soon afterwards the first molt takes place. 11 After the second molt in April—May the third instar larva is full grown within 25 days and emergence is usually effected from the wing pads of the host pupa. The larva pupate outside the hostbody in the litter. The duration of the pupal stage is about 4 weeks in average.

Synthesis of Chiral trans-Epoxides

A general, asymmetric route to various trans-epoxides is presented by the authors. The key step to enantioselectivity is an asymmetric, organocatalytic α-chlorination of aldehydes with prolinamide (1). Subsequently, addition of organolithium reagents to α-chloro aldehyde 2 with good to excellent diastereoselectivities (dr = 8:1 up to 20:1) and epoxide formation leads in direct sequence to alkynyl-, trans-alkenyl-, cis-alkenyl-, phenyl-, and alkyl-substituted trans-epoxides. This methodology, completed by Lindlar reduction of diynes, was applied in a three-step synthesis of trans-epoxide-containing insect sex pheromones isolated from female pine looper moth Bupalus piniarius (3) and female tussock moth Orgyia postica (4).

Radical mediated stereoselective synthesis of meso-7,11-dimethylheptadecane, a female sex pheromone component of the spring hemlock looper and the pitch pine looper

meso-7,11-Dimethylheptadecane, a female sex pheromone component of the spring hemlock looper and the pitch pine looper, was synthesized from ethyl 2-(bromomethyl)propenoate in nine steps and 14% overall yield. The key step in the synthesis is the highly diastereoselective chelation-controlled radical reaction of diethyl 4-benzyloxy-2,6-dimethyleneheptanedioate with pentyl iodide performed in the presence of 6 equiv of MgBr 2·OEt 2.