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Chemical control is widely used to control the Japanese pine sawyer beetle, Monochamus alternatus, but strong chemical regulations require an environmentally sound management strategy. In this work, we investigated the use of entomopathogenic fungi and their application as a means of practical pest management. Thirty-two diverse species of fungal isolates were assayed against adult pine sawyer beetles using a contact method under laboratory conditions, and four isolates showed over 70% virulence consequently. These isolates, two each of Beauveria bassiana and Metarhizium anisopliae were sprayed on the adult beetles at 1 × 107 conidia/ml in plastic containers, respectively. The M. anisopliae-treated adult beetles showed 67% mortality. M. anisopliae isolates JEF-197 and JEF-279 demonstrated dosage-dependent insecticidal activity. Following the laboratory experiments, semi-field trials were conducted in young pine trees under high (RH 94%) and low (RH 35%) humidity conditions. In the high humidity conditions, most of the adult beetles stayed on the top of the branches. When the two M. anisopliae isolates were sprayed on the beetles, they showed ca. 50–70% insecticidal activity 11 days after application. In contrast, in low humidity conditions, the adult beetles tried to move off the branches and onto the soil. When the beetles reached the JEF-197 and JEF-279-treated soil, we measured >90% insecticidal activity. This work suggests that M. anisopliae was the most virulent entomopathogenic fungus against adult Japanese pine sawyer beetles, and this forest insect could be ecologically controlled by the spray and soil application of the M. anisopliae isolates.

With global warming, recent winters in Switzerland have been milder than in previous decades, and this trend is predicted to continue. Survival during the cold season could increase for insect species sensitive to winter cold events. Forest pests, such as the pine processionary moth (Thaumetopoea pityocampa) and green spruce aphid (Elatobium abietinum), as well as some crop pests, such as the southern green stink bug (Nezara viridula), could overwinter more easily. These species are affected by temperatures below –12°C or below –8°C. In this study, we examined whether changes in winter minimum temperatures (Tmin) could potentially favour the winter survival of these pest species in various places in Switzerland. We analysed long-term daily Tmin data from the period 1980–2019 at 67 locations. We then used two climatic scenarios (RCP2.6 and RCP8.5) to analyse daily Tmin in 2020–2099. We determined the number of days with Tmin below –8°C or –12°C and the frequency of years with at least one day below these thresholds. Our results show that the frequency of cold days has decreased over the last 40 years, even though winter Tmin has increased less than yearly Tmin. However, the –8°C threshold was still reached in most years, except on the Southern side of the Alps. The –12°C threshold was reached almost every year above 800 m, but infrequently at lower elevations. Our results indicate that, by the end of the 21st century, temperatures below –12°C will occur only infrequently up to 1700 m in Switzerland, and years with occurrences of temperatures below –8°C will become rare at lower elevations. Future temperature conditions can thus be expected to favour some crop pests, by enabling them to overwinter more easily on the Swiss Plateau, as well as some forest pests, which will likely reach higher elevations.

Carbaryl is regarded among the most effective, economically viable, and ecologically-compatible insecticides available for protecting conifers from bark beetle attack in the western United States. Treatments are typically applied in spring prior to initiation of bark beetle flight for that year. We evaluated the efficacy of spring and fall applications for protecting individual lodgepole pine, Pinus contorta Dougl. ex Loud, from mortality attributed to mountain pine beetle, Dendroctonus ponderosae Hopkins, the most notable forest insect pest in western North America. Both spring and fall treatments of 2.0% a.i. carbaryl (Sevin ® SL) were efficacious for two field seasons, while results from a third field season were inconclusive due to insufficient beetle pressure. We discuss the implications of these and other results to the management of D . ponderosae .

Model testing procedures represent a major challenge in the development of agent-based models (ABMs). However, they are required stages for a model to be accepted and to serve as a forecasting, management or decision-making tool. This study presents a comprehensive approach for testing ForestSimMPB, an agent-based model (ABM) designed to simulate mountain pine beetle (MPB), Dendroctonus ponderosae Hopkins, outbreaks at the scale of individual trees. ForestSimMPB is a complex system model that is using swarming intelligence, capable to represent individuals’ behaviours and spatial interactions that influence their surrounding environment. Swarm Intelligence (SI) methods are integrated into the ABM in order to reproduce the collective reasoning and indirect communication of autonomous agents representing MPB behaviour within the forest environment. Model testing approach consist of verification, calibration, sensitivity analysis, validation and qualification stages. Model testing is accomplished by simulating MPB infestations using both the ForestSimMPB model and a Random–ABM model that serves as a null model. Outcomes comparison and assessment are performed using raster-based techniques as well as spatial metrics. Aerial photographs of the British Columbia, Canada study sites are used in this model testing approach. Results indicate that ForestSimMPB model representations of MPB outbreaks are more similar than Random model representations to the spatial distribution of MPB-dead trees.

A decision support system (DSS) for improved management decision making and to reduce impacts of forest insect outbreaks was developed and implemented for two defoliators, hemlock looper (Lambdina fiscellaria fiscellaria Guen.) and balsam fir sawfly (Neodiprion abietis Harris), in District 15, a 336,805 ha forest managed by Corner Brook Pulp and Paper Ltd. in western Newfoundland, Canada. Over the past 15 years, 56% and 12% of the landbase were defoliated by balsam fir sawfly and hemlock looper, which had major effects on forest growth and yield. Relationships between reduced growth and survival and cumulative defoliation were quantified for each insect, to permit calculation of relative impact per forest stand as a function of defoliation, stand age, and species composition. These were integrated into a forest estate model to project effects on timber supply for 25 years. Defoliation during 1996–2008 was estimated to reduce total operable softwood growing stock and softwood harvest level by 26% and 31%, respectively, for balsam fir sawfly, and by 2–3% for the smaller-scale hemlock looper outbreaks. Given the long-term influence on forest structure, effects of defoliation on yield were projected to continue for up to 60 years after defoliation ceased. Sensitivity analysis using different defoliation scenarios suggested that maximum reductions in harvest levels could be reduced from 40% to 17% by protecting the most susceptible 25% of the landbase using biological insecticides, and minimized further to 9% by re-optimization of harvest schedules to reduce losses. This DSS provides a tool to help forest managers decide when and where to use biological insecticides, and how to use rescheduling of harvest, forest restructuring or planned salvage to reduce future losses.

Aerial surveys provide valuable information on the scale and severity of defoliation and mortality caused by forest insects. However, methods to estimate the losses in growth using aerial survey data are not available. This study presents a method to link aerial survey data of location and severity of insect defoliation to tree ring series of radial growth in order to quantify potential growth losses due to defoliation. The method includes estimation of potentially confounding effects of climate. As an example we used aerial surveys of hemlock looper defoliation in the Mt. Revelstoke region of British Columbia, and tree ring series of radial growth of 351 western hemlock trees located in 22 plots and exposed to various levels of periodic defoliation. An autoregressive conditional heteroskedasticity time-series model (ARCH) of standardized growth indices identified significant direct and lagged effects of climate and defoliation on radial growth between 1930 and 2005. Defoliation effects were statistically significant in all plots (P < 0.05). The variation in both timing and strength of estimated growth reductions varied considerably among plots. During years of observed defoliation the radial growth was reduced by an average of 10%. Growth reductions attributed to defoliation were most pronounced in the second and third year of a looper outbreak. Our modelling approach linked tree ring data to aerial survey data of defoliation through a logistic distance dependent threshold function and affords a quantitative estimation of regional growth losses.

Discrete mathematical model is selected for description of green oak leaf roller (Tortrix viridana L.) population dynamics. Experimental data set from Rubtsov [Rubtsov, V.V., 1992. Models of Oscillation Processes in Forest Ecosystems, Forest Institute, Moscow, Russian Federation, p. 39 (in Russian)] is analyzed from the standpoint of phenomenological theory of forest insect population dynamics [Isaev, A.S., Khlebopros, R.G., Nedorezov, L.V., Kiselev, V.V., Kondakov, Yu. P., 1984. Dynamics of Forest Insects Populations, USSR, Nauka, Novosibirsk, p. 224 (in Russian); Isaev, A.S., Khlebopros, R.G., Nedorezov, L.V., Kiselev, V.V., Kondakov, Yu.P., Soukhovol'sky, V.G., 2001. Population Dynamics of Forest Insects, Russian Federation, Nauka, Moscow, p. 347 (in Russian)]. For checking hypotheses confidence for fitting of experimental time series, Moran–Ricker model, Maynard Smith–Slatkin model, and some others are used. Selection of statistical criteria for estimating parameter's values is discussed. In addition, probabilities of realizations of several dynamical regimes are estimated.

Wood borers are important forest insect pests and difficult to be controlled owing to their concealed behavior. However, parasitic wasps can effectively ascertain and parasitize wood borers as well as other concealed pests by using special searching, finding and attacking mechanisms, which have been developed during the course of long-term coevolution with their hosts. The present paper summarizes the behavioral mechanisms of parasitic wasps involved in searching and locating their concealed hosts. Parasitic wasps can accurately find the location of their hidden hosts and then parasitize them, usually by using olfactory semiochemicals from hosts (lavare and adults), host frass and symbiotic microorganisms in host galleries; visual signals from color contrast of plant surface; contact stimuli from characters of host physical defense; substrate vibrations produced by host feeding and movement; infrared radiation from host activities and metabolizability. Some parasitic wasps may integrate the information of several stimuli from different sources to enhance the reliability and accuracy of host locations. In addition, the potentials for utilizing the host location signals of parasitoids in biological control are discussed.

From 1920 to 1989, approximately 847,000 ha of Alaska spruce (Picea spp.) forests were infested by spruce beetles (Dendroctonus rufipennis). From 1990 to 2000, an extensive outbreak of spruce beetles caused mortality of spruce across 1.19 million ha of forests in Alaska; approximately 40% more forest area than was infested the previous 70 years. This review presents some of the most important findings from a diversity of research and management projects from 1970 to 2004 to understand the biology, ecology, and control of this important forest insect, and the causes and effects of their outbreaks. We suggest that future research should examine the long-term effects of the spruce beetle outbreaks and climate variability on forest ecosystems in the region. Research into how different management actions facilitate or interrupt natural successional processes would be particularly useful.

To better understand the role of habitat quality and boundaries on population dynamics at the landscape scale, we develop a model combining a spatially implicit approach, a spatial population Leslie-type model and an implicit model of habitat fragmentation. An original approach of elasticity permits to identify which types of element and boundary influence the most population viability according to the wood fragmentation degree. The studied species is a corridor forest insect sensitive to fragmentation ( Abax parallelepipedus, Coleoptera, Carabidae). We show that a single large patch of wood is better than several small patches for the population viability. To cite this article: J.-B. Pichancourt et al., C. R. Biologies 329 (2006).

In this paper we consider the method for the restoration of phase portrait structure of population dynamics and apply this method for analysis of experimental data on the population dynamics of Dendrolimus pini L. The method is based on the results of phenomenological theory of forest insect population dynamics (Isaev, A.S., 1979. Lesovedenie 3, 27–42; Isaev, A.S., 1984. Nauka, 74–82.) and includes the elements of statistics, cluster analysis and knowledge of trajectory's behavior of ordinary differential equation's systems. Using the method allows determination of such important features of phase plane as the value of stable level, structure and boundaries of the stable zone, behavior of the threshold curve which separates the stable and outbreak zones and coordinates of ‘point of escape’ etc.

Six basic phase portraits differing in character and in the number of their equilibrium behaviour regimes were suggested in the classification of forest insect population dynamics. The portraits graphically illustrate six types of dynamic behaviour of numbers of the system "phytophage-entomophage": two types of stable equilibrium dynamics (stationary and oscillatory) and four types corresponding to outbreaks of mass reproduction-fixed, permanent, reversive and true outbreaks, respectively. In this paper we consider the single parameter model, with its parametric domains realizing a wide spectrum of phase dynamics, both basic and transitional. The changes in the phase portraits are accompanied by the bifurcations in the model. The results of these analyses are in agreement with the "stability principle of mobile ecological systems" and may supply its parameter substantiation at the model level. Copyright 1997 Academic Press Limited

The 51.2 million ha of productive forest land in British Columbia are surveyed annually by the Forest Insect and Disease Survey of Forestry Canada. The development of provincial pest management capabilities is reviewed from their creation in 1980 through to their present organization in six regions across British Columbia. Basic research is carried out at Universities and at Forestry Canada while the operational implementation of pest management is the responsibility of the pest management (forest health) personnel in the B.C. Ministry of Forests.

A graphical technique is demonstrated which, when combined with any resource simulation model, permits the resource manager to explore the effects of different management options. Also, this technique (nomogram or response surface) permits derivation of “optimal solutions” given particular objectives. Examples of the methodology are given for the spruce budworm—forest system in eastern Canada. Effects of several kinds of uncertainties are dicussed, including uncertainties in model assumptions, management precision, future objectives and system evolution. The graphical nature of nomograms helps managers and analysts to grasp more easily the complicated behavior of ecological systems models. Finally, the role of computer models in decision-making is discussed.