Insect Pest Outbreaks Research Articles

NURSERY PEST PROBLEMS ON Acacia mangium, Cinamomum cassia and Illicium verum IN BAC KAN PROVINCE, VIETNAM

Acacia mangium, Cinamomum cassia, and Illicium verum are pivotal forestry species in Bac Kan province, where they contribute significantly to economic and environmental welfare. A. mangium's wood is essential for the pulp industry, while C. cassia and I. verum provide essential oils with extensive industrial applications. Despite their economic value, increased plantation areas have exacerbated insect pest outbreaks, affecting tree growth and yield. However, the focus of previous research on insect pests has primarily been on plantations, leaving nursery infestations largely unexplored. This study aims to overcome this gap by investigating insect pest species diversity in nurseries in Bac Kan province. Field observations and standard plot surveys were conducted in Cho Moi district and Bac Kan city, resulting in the collection of 72 survey forms. The survey revealed significant insect pest species compositions in A. mangium, C. cassia, and I. verum nurseries. Notably, Helopeltis theivora was identified as the primary pest infesting young A. mangium trees, while Echinothrips sp. emerged as the main pest species in C. cassia nurseries, and others affected I. verum nurseries. These findings underscore the need for ongoing monitoring and research to develop effective pest management strategies. Such insights are crucial for sustaining the economic and environmental benefits of these forestry species in Bac Kan province.

Is It Possible to Predict a Forest Insect Outbreak? Backtesting Using Remote Sensing Data

In this study, methods are proposed for analyzing the susceptibility of forest stands to attacks by forest insects on the basis of Earth remote sensing data. As an indicator of the state of forest stands, we proposed to use a parameter of the sensitivity of a vegetation index (normalized difference vegetation index; NDVI) during a vegetative period to changes in the radiative temperature of the territory (land surface temperature; LST) determined from satellite data of the Terra/Aqua system. The indicator was calculated as a spectrum of a response function in an integral equation linking changes of NDVI to those of LST. Backtesting was carried out using data from two outbreaks of the Siberian silk moth Dendrolimus sibiricus Tschetv. and outbreaks of the white mottled sawyer Monochamus urussovi Fischer and of the four-eyed fir bark beetle Polygraphus proximus Blandford in taiga forests of Krasnoyarsk Territory in Russia. In addition, the state of fir stands in the year 2023 was examined when damage to the forest stands was not yet noticeable, but Siberian silk moth adults were found in pheromone traps. It was shown that the proposed indicator of susceptibility of forest stands changed significantly 2–3 years before the pest outbreak in outbreak foci of the studied areas. Thus, the proposed indicator can be used to predict outbreaks of insect pests. The proposed approach differs from commonly used remote sensing methods in that, rather than using absolute values of remote indicators (such as, for example, NDVI), it focuses on indicators of the susceptibility of these remote indicators to the characteristics of the natural environment. Since any given point on the planet is characterized by a seasonally varying temperature, it is always possible to determine the sensitivity of a remote sensing indicator to changes in the environment that are not directly related to the absolute value of the indicator. Future studies are expected to examine susceptibility indices as a function of forest stand location and species, and to examine the length of spatial correlation of susceptibility indices, which may provide information on the possible extent of future insect outbreaks.

Turmeric shortens lifespan in houseflies.

Climate change poses a significant threat to food security and global public health with the increasing likelihood of insect pest outbreaks. Alternative ways to control insect populations, preferably using environmental-friendly compounds, are needed. Turmeric has been suggested as a natural insecticide with toxicity properties in some insect groups. However, empirical evidence of the effects of turmeric - and their interaction with other ecological factors such as diet - on insect survival has been limited. Here, we tested the effects of turmeric and its interactions with diets differing in protein source in the common housefly, Musca domestica. We found that turmeric shortened lifespan independent of diet and sex. Females in turmeric diets were heavier at death, which was likely driven by a combination of relatively lower rates of body mass loss during their lifetime and a higher percentage of water content at death. Each sex responded differently to the protein source in the diet, and the magnitude of the difference in lifespan between sexes were greatest in diets in which protein source was hydrolysed yeast; individuals from both sexes lived longest in sucrose-milk diets and shortest in diets with hydrolysed yeast. There was no evidence of an interaction between turmeric and diet, suggesting that the toxicity effects are independent of protein source in the diet. Given the seemingly opposing effects of turmeric in insects and mammals being uncovered in the literature, our findings provide further evidence in support of turmeric as a potential natural insecticide.

Reducing pest pressure and insecticide use by increasing hedgerows in the landscape

Reducing pesticide use while maintaining agricultural production is a key challenge. Ecological theory predicts that landscape simplification is likely to increase insect pest outbreaks and limit their control by natural enemies, and this situation could boost insecticide use. Some studies have indeed detected that simpler landscapes were associated with higher insecticide use, but very few have demonstrated that this association is caused by landscape effects on pest abundance. Here, we analysed insecticide use and pest pressure in response to landscape simplification across 557 arable farms across France. Accounting for potentially confounding covariates, we found that lower cover of hedgerows in the landscape, but not semi natural areas, were associated with higher on-farm insecticide use. We also found that greater hedgerow coverage was associated with lower aphid pest pressure. Specifically, increasing the landscape-scale cover of hedgerows from 1 % to 3 % meant that insecticide use was halved. These findings suggest that restoring hedgerow cover at the landscape scale should be targeted in order to speed-up the ecological intensification of agriculture.

Relevance of molecular systematics in insect pest management

Relevance of molecular systematics in insect pest management

A Novel Ethyl Formate Fumigation Strategy for Managing Yellow Tea Thrips (Scirtothrips dorsalis) in Greenhouse Cultivated Mangoes and Post-Harvest Fruits.

The effects of climate change and shifting consumer preferences for tropical/subtropical mango fruits have accelerated their greenhouse cultivation in South Korea, which has consequently exacerbated the risk of unexpected or exotic insect pest outbreaks. This study used the pest risk analysis (PRA) of greenhouse-cultivated mangoes provided by the Animal & Plant Quarantine Agency in Korea to evaluate the potential of ethyl formate (EF) fumigation as a new pest management strategy against the yellow tea thrips (Scirtothrips dorsalis), which is considered a surrogate pest in the thrips group according to the PRA. The efficacy and phytotoxicity of EF were evaluated in greenhouse-cultivated mango tree (Irwin variety) and post-harvest mango fruit scenarios. EF efficacy ranged from 6.25 to 6.89 g∙h/m³ for lethal concentration time (LCt)50 and from 17.10 to 18.18 g∙h/m³ for LCt99, indicating similar efficacy across both scenarios. Application of 10 g/m³ EF for 4 h at 23 °C could effectively control S. dorsalis (100% mortality) without causing phytotoxic damage to the greenhouse-cultivated mango trees, while post-harvest mango fruit fumigation with 15 g/m³ EF for 4 h at 10 °C showed potential for complete disinfestation of S. dorsalis without compromising fruit quality.

Rapid Assessment of Insect Pest Outbreak Using Drones: A Case Study with Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) in Soybean Fields.

Rapid assessment of crop damage is essential for successful management of insect pest outbreaks. In this study, we investigated the use of an unmanned aircraft system (UAS) and image analyses to assess an outbreak of the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), that occurred in soybean fields in South Korea. A rotary-wing UAS was deployed to obtain a series of aerial images over 31 soybean blocks. The images were stitched together to generate composite imagery, followed by image analyses to quantify soybean defoliation. An economic analysis was conducted to compare the cost of the aerial survey with that of a conventional ground survey. The results showed that the aerial survey precisely estimated the defoliation compared to the ground survey, with an estimated defoliation of 78.3% and a range of 22.4-99.8% in the 31 blocks. Moreover, the aerial survey followed by image analyses was found to be more economical than the conventional ground survey when the number of target soybean blocks subject to the survey was more than 15 blocks. Our study clearly demonstrated the effectiveness of using an autonomous UAS and image analysis to conduct a low-cost aerial survey of soybean damage caused by S. exigua outbreaks, which can inform decision-making for S. exigua management.

Conservation agriculture based crop management practices impact diversity and population dynamics of the insect-pests and their natural enemies in agroecosystems

Human efforts to grow abundant food through the persistent use of resource-intensive farming practices have resulted in declining soil health, and deterioration of ecosystem functions and services. Conservation agriculture (CA) has emerged as a practice to minimize the impacts of conventional resource-exhaustive and energy-intensive agriculture. Minimum soil disturbance, permanent soil cover, and diversification are the key components of CA. Tillage through conventional practices on the other hand has detrimental effects on the soil and environment as it requires deep inversion of soil with instruments such as mouldboard plow, disc plow etc. leaving very less organic matter in soil after establishment of crop. Even though, CA advocates many benefits over conventional agriculture in terms of soil and water conservation, the consequent changes in moisture and temperature regimes due to reduced tillage and surface cover would likely going to influence the biological activity, including insect pests and their natural enemies which dwell within these agroecosystems. The changed crop conditions under CA may favor particular insect communities and their ecological niches. The adoption of such practices may lead to decrease in insect pests with major activity on the crop canopy. However, the activity of the insect pests that spend their maximum life span at the soil surface or beneath the soil surface may increase. Recent insect-pest outbreaks in North-Western India and imbalances reported in Indo-Gangetic Plains point to the need for a better understanding of the inter-relationships between tillage intensity, residue retention, and insect pest population dynamics. The current review analyzes the existing state of knowledge of these dynamics and presents the scenarios that may emerge as CA get more acceptance. This review will help to develop countermeasures to improve performance and ecosystem services of Conservation agriculture (CA) based cropping systems.

Impact of Rice Cultivation Methods on Insect Pest Incidence and Their Management

Under the influence of fluctuating global climate scenario and limited resources of water availability, different methods of rice cultivation like System of rice intensification (SRI), Direct seeded rice (DSR), Alternate wetting and drying (AWD) and Aerobic rice have become popular as alternatives to conventional transplanting method. Due to these shifting cultivation situations, insect pest profiles have also undergone changes with associated influence on beneficial insects and other natural enemies. Multi-location studies carried out under All India Coordinated Rice Improvement Project (AICRIP) have revealed significantly less incidence of major pests like stem borers, planthoppers in SRI compared to normal rice transplanting method. Overall, the SRI method leads to more robust plant health with enhanced capacity to resist pest attacks. In case of DSR, AICRIP studies have consistently revealed higher incidence of all the insect pests in the normal transplanted method compared to DSR. However, few reports have indicated association of insect pest outbreaks with higher seed rate and plant densities. Limited studies have shown that AWD also has the potential to minimize the incidence of insect pests and diseases compared to irrigated rice. However, soil borne pests, particularly root-knot nematode can be more damaging under aerobic conditions. Field cum laboratory studies carried out at ICAR IIRR on impact of cultivation systems on the rich insect biodiversity in rice have revealed association of higher total abundance and greater richness of beneficial insect species with SRI management.

Integration of perennial forage seed crops for cropping systems resiliency in the Peace River region of western Canada

The Peace River region is one of the northern agricultural frontiers in Canada, undergoing farmland expansion as well as intensification with input-intensive industrial agriculture. The cropping systems evolved with the rotations between annual grain and perennial forage crops as a prudent adaptation to fragile, crust-forming, runoff-prone, poorly developed, platy-structured acidic Luvisolic soils. In recent years, there is a decline in the acreage of perennial forage seed crops leading to simplified low-diversity cropping systems with heavy reliance on external inputs. The production systems have been prone to the rapid evolution of herbicide-resistant weeds, and outbreaks of crop diseases and insect pests in the face of global warming. A number of studies conducted in the Peace River region and other parts of North America have shown multiple benefits of integrating perennial forage crops in the cropping systems. By virtue of high root-to-shoot ratio and perennial growth, forage seed crops can provide multiple ecological services in the fragile Luvisolic soil through increased soil organic matter, carbon sequestration, soil biological diversity, soil structural improvement, nutrient mobilization, crop protection and environmental health, thereby creating conducive effects to the resilient performance of the cropping systems. This review discusses the merits of crop rotations in general and those of perennial forage seed crops in particular in the face of changing climate, with special reference to studies conducted in the Prairies and Peace region of western Canada. Research opportunities are highlighted to elucidate multidimensional ecosystem services from diversified cropping sequences integrating perennial forage seed crops.

Reference-aided full-length transcript assembly, cDNA cloning, and molecular characterization of coronatine-insensitive 1b (COI1b) gene in coconut (Cocos nucifera L.).

In the Philippines, 26% of the total agricultural land is devoted to coconut production making coconut one of the most valuable industrial crop in the country. However, the country's multimillion-dollar coconut industry is threatened by the outbreak of coconut scale insect (CSI) and other re-emerging insect pests promoting national research institutes to work jointly on developing new tolerant coconut varieties. Here, we report the cloning and characterization of coronatine-insensitive 1 (COI1) gene, one of the candidate insect defense genes, using 'Catigan Green Dwarf' (CATD) genome sequence assembly as reference. Two (2) splicing variants were identified and annotated-CnCOI1b-1 and CnCOI1b-2. The full-length cDNA of CnCOI1b-1 was 7919bp with an ORF of 1176bp encoding for a deduced protein of 391 amino acids while CnCOI1b-2 has 2360bp full-length cDNA with an ORF of 1743bp encoding a deduced protein of 580 amino acids. The 3D structural model for the two (2) isoforms were generated through homology modelling. Functional analysis revealed that both isoforms are involved in various physiological and developmental plant processes including defense response of plants to insects and pathogens. Phylogenetic analysis confirms high degree of COI1 protein conservation during evolution, especially among monocot species. Differential gene expression via qRT-PCR analysis revealed a seven-fold increase of COI1 gene expression in coconut post introduction of CSI relative to base levels. This study provided the groundwork for further research on the actual role of COI1 in coconut in response to insect damage. The findings of this study are also vital to facilitate the development of improved insect-resistant coconut varieties for vibrant coconut industry.

The effect of climate variability in the efficacy of the entomopathogenic fungus Metarhizium acridum against the desert locust Schistocerca gregaria

Despite substantial efforts to control locusts they remain periodically a major burden in Africa, causing severe yield loss and hence loss of food and income. Distribution maps indicating the value of the basic reproduction number R0 was used to identify areas where an insect pest can be controlled by a natural enemy. A dynamic process-based mathematical model integrating essential features of a natural enemy and its interaction with the pest is used to generate R0 risk maps for insect pest outbreaks, using desert locust and the entomopathogenic fungus Metarhizium acridum (Synn. Metarhizium anisoliae var. acridum) as a case study. This approach provides a tool for evaluating the impact of climatic variables such as temperature and relative humidity and mapping spatial variability on the efficacy of M. acridum as a biocontrol agent against desert locust invasion in Africa. Applications of M. acridum against desert locust in a few selected African countries including Morocco, Kenya, Mali, and Mauritania through monthly spatial projection of R0 maps for the prevailing climatic condition are illustrated. By combining mathematical modeling with a geographic information system in a spatiotemporal projection as we do in this study, the field implementation of microbial control against locust in an integrated pest management system may be improved. Finally, the practical utility of this model provides insights that may improve the timing of pesticide application in a selected area where efficacy is highly expected.

Reproduction does not impede the stopover departure to ensure a potent migration in Cnaphalocrocis medinalis moths.

Despite the importance of reproduction in insects, its relation with multi-stop flight remains poorly understood in migratory species. To clarify whether reproductive maturation commences during the multi-stop flight or after the completion of migration, we conducted physiological and behavioral assays in the rice leaf roller Cnaphalocrocis medinalis with laboratory-simulated conditions and field-captured populations. We found that the ovarian development was significantly promoted by tethered flight treatment for 1-2 nights when compared to the unflown group, while the flight muscle development was not impaired. There was no significant difference in flight duration, flight distance and flight velocity between mated and virgin female moths, indicating that mated moths remained competent for the subsequent flights as did the virgins. Using an integrated field assay, we identified that over 60% of the female moths in the migrating populations captured by high-altitude searchlights in the Immigration period of a season had completed the ovarian development and mating. Sexually mature and mated moths collected in the rice field in the Emigration period were found capable of engaging in migratory take-off, as observed using an indoor monitoring platform. Overall, our findings point out that C. medinalis managed to complete reproductive maturation to a large extent during the multi-stop migratory flight without compromising the migration performance. Such a cost-effective strategy ensures a successful migration for the moths. These findings advance our understanding of the relationship between reproduction and migration, thus shedding light on the development of novel control measures for the outbreak of migratory insect pests.

Investigation on the entomological and beneficial insect pests associated with cucumber (Cucumis sativus) production in South Western Nigeria

Cucumber production has gained recognition as one of the essential market vegetables in Nigeria because of the continued awareness of the numerous health benefits attached to its consumption. This has progressively affected its cultivation, leading to increased insect pest outbreak. Based on the above, the study was conducted at the Ekiti State University Teaching and Research Farm, Ado-Ekiti, to ascertain the entomological and beneficial pest associated with the production of cucumber and the damage caused by each insect. Cucumber variety Cu 999 was planted at a spacing of 30cm x 30cm. Insect feeding modes and frequency of occurrence were recorded on the plant from 6 am to 7 pm in 2 hours slots catches, which were done twice per week. The collected insect pest was identified for the damage caused to the plant. The study shows that insects were found on the stem, leaves and flowers of cucumber, some of them damaged the various parts of these plants while others were beneficial. The collection of each insect obtained consists of insect pest, predators and pollinators there were 23 insect species belonging to fifteen different families and seven orders. Out of these, 23 species belonged to Homoptera (44%), which has the highest frequency of occurrence. This was closely followed by Coleoptera (39%), Hemiptera (21.7%), Orthoptera (13.0%) and Hymenoptera (13%). The other Lepidoptera and Dermaptera had an occurrence of 4.3% each. The study concluded that there were varied degrees of entomological and beneficial insect pest associated with cucumber production.

Early instar mortality of a forest pest caterpillar: which mortality sources increase during an outbreak crash?

AbstractCollapses of insect pest outbreaks are often attributed to delayed density dependence of predation. The forest tent caterpillar, Malacosoma disstria Hübner (Lepidoptera: Lasiocampidae), is an outbreaking pest species defoliating mixed wood boreal forests in eastern Canada. This species presents periodic population dynamics with peaks every 10 years and outbreaks lasting 1–3 years impacting the health of its host tree. We asked about the relative importance of various sources of early‐instar mortality during and after the crash of an outbreak, testing for density dependence. We used a triad set‐up of complete predator exclusion, partial exclusion, and free colonies to distinguish between intrinsic mortality (caused by, e.g., pathogens) and mortality caused by flighted and walking natural enemies, and compared defoliated outbreak sites with control sites. Overall, survival was lowest in the free colonies and increased with partial and complete predator exclusion. Survival was also higher in control than in outbreak sites and higher in the final year of the outbreak than in the following year. We observed no changes in mortality from walking enemies, but an increase in intrinsic mortality and mortality from flighted enemies. in the year following the outbreak. This increase is consistent with density dependence of these mortality sources, but its occurrence in the control sites as well was unexpected. These findings show that mortality from flighted natural enemies and intrinsic source increases after the outbreak, but do not contribute to the population crash. However, they help maintain low endemic levels between outbreaks.

Anticipating B. sempervirens viability in front of C. perspectalis outbreaks, fire, and drought disturbances

Forest ecosystems face an increasing pressure of insect pest outbreaks due to changes in land-use, new climatic conditions, and the arrival of new invasive alien species. Also, insect outbreaks may interact with other shifting disturbances such as fire and drought, that eventually may boost the impacts of pests on forest ecosystems. In the case of alien species, the lack of long-term data and their rapid spread challenges their study and require appropriate new management strategies to cope with them. Here we studied the case of boxwoods (Buxus sempervirens) in Southern Pyrenees under the pressure of the invasive insect box tree moth (Cydalima perspectalis), fire, and drought events. We projected the future of boxwoods through the development of a spatially explicit simulation model and its implementation under different climatic and ecological scenarios. The results showed an initial boxwood decline due to C. perspectalis fast spread but a later stabilization of the population resulting from a fluctuating dynamic. Climate change is expected to reduce overall insect habitat suitability and future negative impacts on boxwoods. Furthermore, boxwood drought-induced mortality and burning will increase under new climatic conditions. Interaction between drought and insect pest conditioning regeneration after defoliation were negligible in our analyses. Boxwood decline was anticipated to be more notorious in locations under 800 m a.s.l. and in habitats where the species dominates the forest understory, while boxwood in open shrub forest types typical of higher elevations will be less endangered. Our results provide valuable information for boxwood and C. perspectalis management in a context of joint disturbance impacts and contribute to a better identification of the role of forest disturbances and their interactions.

The Effects of Temperature on the Development, Morphology, and Fecundity of Aenasius bambawalei (=Aenasius arizonensis).

Simple SummaryDuring biological invasions, insect pest outbreaks often occur because they escape the control of natural enemies from their place of origin. However, some natural enemies can migrate with pests to effectively inhibit their damage. Whether temperature changes can shorten or enhance the reproductive developmental period of accompanying natural enemies is an important determinant of whether they can effectively migrate with pests. Aenasius bambawalei is a predominant accompanying parasitoid of the important invasive pest Phenacoccus solenopsis. To understand the effect of temperature changes on the development of the reproductive systems of this parasitoid, we compared differences in its development, morphology, and fecundity under different temperatures. The results showed that high temperature could significantly shorten the pupal developmental duration, increase the length of the hind tibia, and accelerate gonad development. Our results indicated that moderately high temperature was conducive to the reproduction and development of the parasitoid and may be related to the more females offspring. This is the first report of the impact of high temperature on the pupal development, morphology, and fecundity of A. bambawalei.The effects of high temperature on the developmental, morphological, and fecundity characteristics of insects, including biological invaders and their accompanying natural enemies, are clear. Phenacoccus solenopsis (Homoptera: Pseudococcidae) is an aggressive invasive insect pest worldwide. Aenasius bambawalei (=Aenasius arizonensis Girault) (Hymenoptera: Encyrtidae) is a predominant accompanying parasitoid of this mealybug. Our previous studies showed that temperature change induced an increase in the female offspring ratio of A. bambawalei. However, whether this increase is the result of a shortened or enhanced development period of the reproductive systems of A. bambawalei remains unknown. Here, we compared the pupal development, hind tibia of female adults, and fecundity of A. bambawalei under different temperatures to clarify the development and morphological changes induced by high temperature and to better understand its potential as an accompanying natural enemy. Our results showed that, at a high temperature (36 °C), the pupal developmental duration of A. bambawalei was only 0.80 times that of the control, and the length of the hind tibia was 1.16 times that of the control. Moreover, high temperature accelerated the developmental rate of gonads and increased the numbers of eggs and sperm. These results indicated that experimental warming shortened the pupal developmental duration, altered the hind tibia length of female adults, and facilitated the fecundity of A. bambawalei. These findings will help to understand the adaptation mechanisms of accompanying natural enemies. Furthermore, these findings will help to make use of this behavior to effectively control invasive pests.

Landscape-scale population connectivity in two parasitoid species associated with the spruce budworm: Testing the birdfeeder effect using genetic data.

Periodic and spatially synchronous outbreaks of insect pests have dramatic consequences for boreal and sub-boreal forests. Within these multitrophic systems, parasitoids can be stabilizing agents by dispersing toward patches containing higher host density (the so-called birdfeeder effect). However, we know little about the dispersal abilities of parasitoids in continuous forested landscapes, limiting our understanding of the spatiotemporal dynamics of host-parasitoid systems, and constraining our ability to predict forest resilience in the context of global changes. In this study, we investigate the spatial genetic structure and spatial variation in genetic diversity of two important species of spruce budworm larval parasitoids during outbreaks: Apanteles fumiferanae Viereck (Braconidae) and Glypta fumiferanae (Viereck) (Ichneumonidae). Using parasitoids sampled in 2014 from 26 and 29locations across a study area of 350,000km2 , we identified 1,012 and 992 neutral SNP loci for A. fumiferanae (N=279 individuals) and G.fumiferanae (N=382), respectively. Using DAPC, PCA, AMOVA, and IBD analyses, we found evidence for panmixia and high genetic connectivity for both species, matching the previously described genetic structure of the spruce budworm within the same context, suggesting similar effective dispersal during outbreaks and high parasitoid population densities between outbreaks. We also found a significant negative relationship between genetic diversity and latitude for A. fumiferanae but not for G. fumiferanae, suggesting that northern range limits may vary by species within the spruce budworm parasitoid community. These spatial dynamics should be considered when predicting future insect outbreak severities in boreal landscapes.

Динамика насаждений с участием ели в защитных лесах Подмосковья

The results of dynamic processes occurring in recent decades in the forests of the Moscow region cxontaining spruce and caused by both climate changes and increasing anthropogenic influence are presented. It is demonstrated that the spruce stands in modern conditions are unstable to droughts and outbreaks of insect pests, and in the future they will also be dynamically unstable and tend to decay. The situation is even more complicated due to the ban on continuous logging in the protective forests of the Moscow region and the widespread distribution of monocultures here, which, moreover, continue to be created even now. It is established that the structure of stands by age and diameter is largely determined by the density of the stand and the mixing of species, and is most aligned in pure high-field forests, and the optimal structure in diameter is formed with a proportion of spruce trees of 3–7 units. As a result of long-term observations on permanent sample areas in «Losiny Ostrov», it was revealed that with the natural development of forest communities, the composition of new forest generations is extremely rarely close to the composition of the first tier. In most cases, the development goes towards broad-leaved forests with a predominance of linden. The same tendency to replace coniferous forests with linden forests is shown for plantings where the spruce part of the stand was lost due to the bark beetle. Both on the site of the decayed spruce forests and under the canopy of the preserved ones, a new generation of forest is formed, represented by hardwoods with a small or single participation of spruce. It is recommended to form mixed stands in the spruce forests of the Moscow region with a proportion of spruce of 30…50 %, while a higher proportion of spruce may be acceptable only in small areas (1–2 ha). At the same time, the mass creation of monodominant spruce crops should be avoided.

Soybean plants under simultaneous signals of drought and Anticarsia gemmatalis herbivory trigger gene expression and metabolic pathways reducing larval survival

Climate changes are promoting increases in global temperatures, variability in precipitation, and more frequent insect pest outbreaks. Understanding the molecular mechanisms for the tolerance of both, biotic and abiotic stresses, is critical for the development of improved genotypes and sustainability of productivity under climate change. Thus, we examine the regulatory cascades and metabolic pathways triggered by both drought and insect attack signals. Profiles from the genotypes drought-tolerant (EMBRAPA 48) and resistant to A. gemmatalis infestation (IAC17) were compared with one sensitive to drought/insect attack (BR16). EMBRAPA 48 and IAC17 plants under drought were less susceptible to insect attack, promoting lower caterpillar survival. Survival reductions were not dependent on the drought-tolerance or insect-resistance phenotypes, despite being more pronounced for IAC17. Furthermore, metabolites profiles, gene expression and enzymatic assays lead us to conclude that drought signal by itself was not enough to explain the survival reductions. Protease inhibition activities and expressions of LOX and PI genes correlated with ABA levels, indicating that JA-signalling was potentialized by ABA to enhance the production of deterrent metabolites. Thus, increased ABA levels during drought treatment may be acting synergistically to induce cascades responsive to JA. Thus, regulatory molecular hub(s) integrating signals may be a target to the genetic engineering of plants with multiple tolerances to environmental stresses.