Pear psylla, Cacopsylla pyricola (Förster), is a key pest of pears in the Pacific Northwest United States. Overwintering adults (winterforms) recolonize orchards in late winter from habitat outside orchards. To reduce winterform colonization and subsequent damage, sprays of the repellent particle film, kaolin clay, are recommended from late dormant through bloom. However, many pear growers struggle to make early sprays due to the danger of driving tractors over hilly terrain with lingering winter moisture. To address this challenge, we tested fall applications of kaolin (Surround WP) for suppression of pear psylla the following spring. Experiments were performed on potted trees and commercial orchard-sized plots, with fall kaolin treatments made at 112 kg/ha (120 g/L). Pear psylla adult and egg densities were measured by visual counts, and kaolin residue stability was assessed by relative whiteness of branches using ImageJ. In the days immediately after kaolin applications (fall and spring), kaolin significantly reduced pear psylla adult numbers and increased branch whiteness. Fall kaolin residues visibly declined over the winter, but branches often remained significantly whiter than checks at spring assessments. Likewise, fall kaolin often resulted in significantly fewer adults and eggs than checks the following spring. This study demonstrates that residues from fall-applied kaolin can remain through the winter and reduce pear psylla colonization the following spring. This tactic will be advantageous in orchards that are difficult to spray in early spring, and as a general addition to the pear integrated pest management toolkit.

The compound eye of the family Psyllidae (Hemiptera: Sternorrhyncha) remains one of the least studied among hemipteran insects. Among the approximately 4000 psyllid species worldwide, the pear psyllid Cacopsylla chinensis (Yang et Li) is a major pest of pear trees in China. The ultrastructure of the compound eye of adult C. chinensis was investigated using a transmission electron microscope (n = 12 adult). The eyes are of the apposition type, lacking a clear zone. Each ommatidium features a laminated corneal lens (about 16.9 ± 1.7 μm in diameter and 7.6 ± 1.7 μm in thickness), a eucone crystalline cone, a centrally fused rhabdom formed by eight retinula cells (R1-R8), and both primary and secondary pigment cells. The 57.0 ± 3.6 μm long rhabdom exhibits a two-tiered structure: a distal region comprising R1-R7 and a proximal region composed of R1-R6 and R8, with R7 withdrawing. Throughout this structure, the rhabdomeres of R1-R6 contribute continuously along the entire length, while R7 and R8 are restricted to the distal and proximal regions, respectively. The microvilli of the rhabdom are arranged in two orthogonal directions. Based on the similarity between the compound eye of C. chinensis and those of other diurnal hemipterans, the evolution and function of eyes are briefly discussed.

Abstract The Pear psylla, Cacopsylla pyri L. (Hemiptera: Psyllidae), is the main pest of pears in all pear-growing regions of Turkey as well as in Antalya province (southwestern part of Turkey). Its control mainly relies on the use of synthetic chemical insecticides; however, in last decade, desired levels of control have not been achieved due to development of resistance to these insecticides. Previous studies have shown that entomopathogenic fungi (EPFs) may be a good alternative to pesticides to suppress pear psylla populations. Therefore, the objectives of this study were: (i) to isolate native EPFs from naturally infected individuals of pear psylla in Korkuteli county of Antalya province, (ii) to identify the collected EPF isolates, and (iii) to assess the effectiveness of these isolates against various developmental stages [eggs, young (1st and 2nd instars) and older (3rd and 5nd instars) nymphs, and adults of the pest under laboratory conditions. A total of 19 fungal isolates, including 12 Beauveria bassiana (Balsamo) Vuillemin (Deuteromycota: Hyphomycetes), 3 Penicillium raistrickii Smith, 2 P. chrysogenum Tom and 2 Aspergillus ochraceus Wilhelm (Ascomycota: Eurotiomycetes)] were recovered from 63 fungal-infected psyllid cadavers during a two-year survey. In initial screening tests, 9 B. bassiana isolates, producing ≥ 20% mortality in the nymphal (young or older) stages of C. pyri , were also confirmed by molecular identification and included in the virulence assays for further evaluation against the pest. All 9 isolates were tested at three different conidial concentrations (1 × 10 5 , 1 × 10 6 and 1 × 10 7 conidia/ml), using spray method. The results of virulence assays showed that all 9 B. bassiana isolates had low ovicidal and adulticidal activity (both egg and adult mortalities were below 20%) while they caused significant mortalities on young nymphs. Of the 9 B. bassiana isolates tested, two isolates (AKBBPN2 and AKBBPN6) were the most virulent, causing 94.2 and 92.7% mortalities, respectively, in young nymphs within 14 days at the highest concentration (1 × 10 7 conidia/ml). The findings of the current study indicated that these two B. bassiana isolates from C. pyri nymphal cadavers may provide an essential basis for the development of bioproducts, as well as a promising alternative method for controlling the pest.

Abstract Psyllids are small (2.5–4 mm), phytophagous, plant sap-feeding insects. Several species, in the genus Cacopsylla , are known as pests of fruit trees in Europe and adjacent countries. Interestingly, some species are multivoltine, such as the pear psyllids Cacopsylla pyri and C. pyricola , while closely related psyllid species of pear, plum, and apple ( C. pyrisuga , C. pruni , and C. picta, resp.) are univoltine and migrate between Rosaceae fruit tree species and evergreen conifers in higher regions. Therefore, the latter species have to cover great distances between their two diverging habitats. To uncover adaptations of the flight behavior and ability to the different life-history strategies, the flight of migrating ( C. pruni ) and non-migrating ( C. pyri and C. pyricola ) psyllids is investigated with a flight mill, showing that the seasonal migration of C. pruni correlates with the motivation to initiate long straight distance flights, indeed. Interestingly, C. pyri and C. pyricola showed great differences in their flight motivation and performance, indicating a greater dispersal propensity of C. pyri than C. pyricola . In addition, the determination of the protein, soluble carbohydrate, and glycogen content of pear psyllids revealed the consumption of carbohydrates during the psyllids’ flight. The content of the energetic resources is discussed in relation to their flight propensity.

Integrated pest management programs often use pesticides alongside behavioral tactics, such as mating disruption, to manage pests. Pest management using biotremology, the study of vibrations produced by organisms, is gaining attention but requires substantial knowledge of pests and their environment. Here, we built on previous characterizations of vibrational mating signals in pear psylla to assess if pear psylla (Cacopsylla pyricola Förster) communication behavior can be exploited for pest management. Specifically, we conducted greenhouse experiments to test the efficacy of 3 vibrational playback treatments for mating disruption: (i) control, (ii) white noise, and (iii) male mating signals, using 2 delivery methods: (i) plant substrate and (ii) trellis wire; these 2 methods assessed whether devices attached directly to pear saplings or trellis wire supporting saplings provided similar results. We also conducted experiments in pear orchards to assess effectiveness of vibrational playbacks as trap supplements. In the greenhouse, white noise and male mating signals delivered through plant substrates reduced pear psylla offspring in 1 of 3 experiments, but never when delivered through trellis wires. Sticky traps in orchards supplemented with vibrational signals trapped more adults and females than sticky traps alone. The results of this study suggest that pear psylla vibrational communication may be exploited for pest control and pest monitoring, but variable efficacy among experiments suggests a need for further examination into delivery methods.

Temperature critically governs seasonal polyphenism, shaping species distribution and invasion dynamics. Although vanilloid‐type transient receptor potential (TRPV) channels are conserved thermal sensors, their mechanistic role in orchestrating seasonal polyphenism remains unresolved. The pear psyllid Cacopsylla chinensis exhibits striking temperature‐dependent transitions: warm spring temperature triggers winter‐form adult females to oviposit and irreversibly transform into summer‐forms, providing a model to dissect this phenomenon. Here, how TRPV‐mediated thermal sensing regulates this process. It is demonstrated that exposure to 25 °C – a critical ecological threshold‐induces an orchestrated shift in energy metabolism, follicular epithelium remodeling, and ovarian maturation, culminating in phenotypic transformation. Central to this process is the assembly of functional heterotetrameric TRPV channels comprising interdependent subunits CcIav and CcNan, which directly perceive the 25 °C thermal signal. Mechanistically, CcIav/CcNan activation triggers a phosphorylation cascade via protein kinase CcPKCα, subsequently potentiating adipokinetic hormone signaling through CcAKHR. This axis synchronizes energy metabolism reprogramming with reproductive tissue reorganization to drive polyphenic switching. Significantly, the evolutionary conservation of this TRPV is validated heterotetramer‐dependent thermosensation mechanism across three phylogenetically diverse insect species. This work delineates a previously unrecognized CcIav/CcNan‐CcPKCα‐AKH/CcAKHR signaling module essential for insect seasonal adaptation and pioneers a receptor‐targeted strategy for disrupting psyllid population cycles in agroecosystems.

This study evaluated mortality of winterform pear psylla after treatment with four commercially available horticultural oils delivered in both heated and non-heated sprays. The aim was not to compare efficacy of the oil products, rather validate previous studies reported on efficacy of heated oil spray (HO) using various oils. Furthermore, this study aimed to validate fumigation effects of heating oils through additional investigation of the efficacy of a heated water spray (HW) treatment. Four oil products – Cinnerate®, Thyme Guard®, Purely Green Bio-Pesticide and PureSpray™ Green – were tested at minimum label recommended concentrations. For each oil product, the following treatments were conducted: 1) untreated control, 2) HW spray, 3) unheated oil (UO) spray, and 4) HO spray. Each treatment was replicated 5 times against winterform adult pear psylla in a bioassay format. The spray was applied using a single hollow cone nozzle (D8DC45, VMD = 165 μm) at 0.3 and 0.6 m from the target organism. Mortality was evaluated at 24 hours after spray. Regardless of oil product, when applied at 0.3 m from the psylla, the mortality response for HO was not different from HW, but both had significantly higher mortality than the control. At 0.6 m from the nozzle, HW failed to increase psylla mortality relative to the control. However, Purely Green Bio-Pesticide, significantly increased psylla mortality relative to the HW treatment, but heating this specific oil did not alter its efficacy. Similarly, remaining pesticide products failed to show significant difference between HO and UO applications at 0.6 m. Overall, spray distance appears to be a limiting factor for successful delivery of a heated spray, and that tested oils did not improve their efficacy with heating.

Pear psylla (Cacopsylla chinensis), a major pear tree pest widely distributed in China, is increasingly affecting the productivity of orchards. This species exhibits seasonal polyphenism with two distinct forms, namely, a summer form and a winter form. Through topically applying Beauveria bassiana conidial suspensions to the abdominal cuticle of C. chinensis, we demonstrated that the entomopathogenic fungus B. bassiana exhibits significant yet phenotypically divergent virulence against these two forms. Using PacBio SMRT sequencing and Illumina RNA-seq, we analyzed transcriptomic changes post-infection, revealing form-specific immune responses, with 18,232 and 5027 differentially expressed genes identified in summer- and winter-form pear psylla, respectively, and a total of 3715 DEGs shared between the two seasonal phenotypes. In summer-form individuals, B. bassiana infection disrupted oxidative phosphorylation and downregulated immune recognition genes, cellular immune-related genes, and signaling genes, along with the upregulation of the immune inhibitor serpin, indicating immunosuppression. Conversely, in winter-form individuals, immune-related genes and glycolytic rate-limiting enzymes were upregulated after infection, suggesting that the winter-form immune system normally responds to B. bassiana infection and supports efficient defense through metabolic reprogramming to fuel energy-demanding defenses. These findings advance our understanding of C. chinensis/B. bassiana interactions, providing a basis for elucidating immune regulation in seasonally polymorphic insects. The results also inform strategies to optimize B. bassiana-based biocontrol, contributing to sustainable pear psylla management.

Pear (Pyrus communis) is an important fruit crop cultivated worldwide, including the temperate regions of India, particularly Jammu and Kashmir. Pear Psylla (Cacopsylla pyricola (Foerster) has emerged as a significant pest, causing substantial losses by stunting tree growth, reducing fruit size leading to premature leaf drop. The present study investigated the influence of various abiotic factors such as temperature, humidity and rainfall on the seasonal incidence and population dynamics of Pear Psylla in four locations from two districts viz., Baramulla and Srinagar, Kashmir. Regular pest monitoring and meteorological data revealed that maximum and minimum temperatures had a positive correlation with Pear Psylla populations while rainfall and maximum relative humidity were negatively correlated. Regression analysis showed that these climatic factors accounted for up to 95% of the variation in pest populations. The results of the evaluation of different insecticides revealed that Cyantraniliprole 10.26% OD with an efficacy of 92.74%, proved to be the most effective followed by Acetamiprid 20% SP (90.87%). These findings highlighted that the optimal temperature range for Psylla development was between 27°C and 29°C suggesting that the weather conditions played a crucial role in fluctuating pest population and can govern the integrated pest management strategies.

Abstract. The research results of 2024 against the background of increased impact of anthropogenic loads and changes in regional weather conditions are the developed methods and elements of biologized technologies for increasing the resistance of fruit plants to a complex of factors and anthropogenic impacts based on the identified dependencies and interrelations of the components of fruit agrocenoses. New knowledge gained: about the patterns of changes in physiological and biological parameters of plants, productivity and quality of apple fruits of domestic varieties under the influence of biologized techniques; about the patterns of changes in soil properties in apple tree plantations from the use of agrotechnological methods to reduce the accumulation of harmful salts during drip irrigation; about the patterns of response of released and promising pear varieties to changing environmental conditions in order to increase the regularity of fruiting and productivity. Algorithms have been developed for the formation of a system for increasing the resistance of pear plants to low temperatures in order to increase regularity of fruiting and productivity. Scientifically based parameters of soil suitability for the identified scion-rootstock combinations of fruit crops were determined, taking into account the new knowledge obtained. The method of extracting total DNA from soil (leached chernozem) has been improved to assess the degree of soil fatigue in fruit plantations. Experimental data on the bioecology of the pear psylla on pear were obtained and the Database Bioecological features of the development of Psylla pyri L. and determination of the biological effectiveness of drugs in controlling its population was registered. The scientific basis for managing the number of pests in orchard cenoses in biorational differentiated protection systems has been developed. Scientifically based parameters for the use of chemical and biological preparations have been developed to control coccomycosis and cherry fruit fly on cherries under conditions of increased abiotic and anthropogenic impacts. Keywords: orchard cenoses, stress impacts of the environment, transformation of soil parameters, varietyoriented technologies, physiological and biological indicators of plants, nutrition optimization, control of pathogens and pests.

Abstract Enhancing ground cover vegetation may favour biological pest control. This research aimed to test the effect of cover management on the abundance of natural enemies and pest control in pear orchards. Two types of cover management (i.e., sown/mown cover) were tested in an organic pear orchard during three years in southern Spain. The cover and pear trees were sampled periodically between April and June to estimate the abundance of arthropods. The abundance of all the groups of natural enemies, including ants, spiders, predatory thrips, hemipterans and four families of parasitoids, as well as phytophagous insects such as aphids and psyllids, was significantly higher in the vegetation of the sown than in the mown cover. The sown cover was found to significantly reduce the abundance of aphids on pear trees, while it had a neutral effect on Cacopsylla pyri. This reduction in aphid numbers could be mainly attributed to the increase in the abundance of spiders and predatory mirids on the trees with the sown cover. In contrast, the sown cover was found to significantly reduce the abundance of the ant Lasius grandis on pear trees in relation to the mown cover. Overall, the management of the cover had a stronger effect on the assemblage of arthropods on the understory vegetation than on pear trees. The increase of the abundance of natural enemies on pear trees with the sown cover could have been due to their movement from the cover and/or the reduction of harassment due to the lower ant activity.

Pear psyllid (Cacopsylla pyri) is the dominant pest of UK pear orchards, with an estimated cost of £5 million per annum. Insecticide withdrawal and increased pesticide resistance of C. pyri have led many growers to depend more on natural enemies for pest management, including earwigs. However, there is concern how phenological events may shift with future climate change, which may result in phenological mismatches. This study aimed to determine shifts in timing of phenological events within an agroecosystem and predict phenological mismatches or synchronies between trophic levels. We evaluated three models: the C. pyri phenology model, the earwig degree day model and the PhenoFlex model (flowering time). Phenological events predicted by models included: first, full and last flowering time for Pyrus communis; peak psyllid abundance date for first-generation (G1) C. pyri nymphs and second-generation (G2) eggs, nymphs and adults; and peak abundance date for stage 4 Forficula auricularia and adults. Findings indicated that the timing of phenological events was advancing for all trophic levels, becoming significantly earlier under the current time period. Furthermore, predictions indicated that timing events would continue to advance under the RCP8.5 scenario. However, not all phenological events advanced at the same rate; the date of peak C. pyri G1 nymph abundance advanced at a higher rate than full flowering time, which could result in a phenological mismatch by 2071. Conversely, C. pyri and F. auricularia showed phenological synchrony, with peak abundance dates advancing at a similar rate, which could be beneficial for future biological control.

Conservation biological control in agriculture primarily relies on avoiding pesticides that may harm key natural enemies. In temperate tree fruit crops, the European earwig, Forficula auricularia (L.) has only recently become appreciated as an important predator of economic pests, particularly woolly aphids and pear psylla. Therefore, the non-target effects of orchard pesticides on earwigs are largely understudied. This is particularly true for herbicides, which earwigs are likely to be exposed to due to their foraging behavior moving between the canopy and the ground cover. We tested residues of formulated pesticides (8 insecticides and 7 herbicides) commonly used in tree fruit crops for lethal and sublethal (movement, predation rate) effects on adult female earwigs. Two herbicides, paraquat and glufosinate, and one insecticide, spinetoram, were acutely toxic to earwigs within 72 h. No tested pesticides altered earwigs' movement or resting behavior compared to the control. The insecticides spinosad and cyantraniliprole and the herbicides 2,4-D, glufosinate, halosulfuron, rimsulfuron, and oxyfluorfen reduced earwig predation on green peach aphids. Therefore, these pesticides may reduce earwig predation on pests in orchards. Our results suggest that some pesticides are of greater risk, and thus, should be carefully considered or better timed when used in tree fruit orchards where earwigs are considered for conservation or augmentative biological control.

Abstract. Pear is a valuable fruit crop, the fruits of which are rich in various minerals and vitamins. On the territory of the Krasnodar region, less than 4% of the total area of pome crops is accounted for by pears. One of the main reasons why farms refuse to cultivate pears is the high cost of controlling the number of Psylla pyri L. In this regard, the goal of our study is to research the resistance of pear varieties to pear psylla in different gardening areas of the region. The results of the research and their subsequent practical application will contribute to an increase in the area of pear plantations. The research was carried out in the Prikuban zone of the central and zakuban gardening subzones of the Krasnodar region in 2021-2024. The assessment of the damage of 14 pear varieties by Psylla pyri L. was carried out by weekly monitoring of the pest development throughout the growing season. It was found that in the early spring period, preference for egg laying is influenced by both the physiological features of the structure of shoots and buds, and the phenological phase of pear development. It was noted that the maximum oviposition is observed on early ripening pear varieties. Pear varieties have been identified, which have the least number of nymphs in the summer: Bere Klerzho, Avgustin Perron, Krasnodarskaya letnyaya, Talgarskaya krasavicza. It was found that in these varieties the sugar content in the leaves phloem sap is 6-10 mg/g of crude matter, in the severely damaged varieties Zimnyaya Mlievskaya and Moldavskaya rannyaya at the level of 14-17 mg/g of crude matter. Keywords: pear, varieties, stability, pear psylla

Abstract Pear psylla, Cacopsylla pyricola (Foërster), is the most economically harmful arthropod pest of pears in the Pacific Northwest (PNW). The phloem-feeding nymphs produce a sticky, sugar-based excrement called honeydew, which causes cosmetic fruit injury, tree stress, and inconvenience to orchard workers. Management of pear psylla has historically prioritized season-long spraying with insecticides that have substantial nontarget effects on natural enemies. However, control has been an ongoing challenge in many growing regions due to pear psylla’s resistance to insecticides, and natural enemies are virtually absent in orchards with aggressive pesticide programs near harvest, leading to rapid increases in pear psylla. Subsequently, excessive numbers of overwintering pear psylla create a regional overabundance of the pest the following spring. Integrated pest management (IPM) programs for pear psylla prevent this cycle with effective cultural tactics and insecticides that are minimally disruptive to natural enemies. Still, IPM adoption seems to be regionally variable. The major growing region of the Wenatchee Valley in Washington State has been reluctant to adopt IPM and, consequently, continues to struggle with pear psylla management. Other areas, such as Hood River, Oregon, and Okanogan, British Columbia, have made significant improvements in pear psylla management through the adoption of area-wide IPM. This review will provide an overview of pear psylla biology, pest status in the PNW, primary IPM tactics, and various elements that have either challenged or advanced the pear industry’s adoption of IPM.

Abstract European earwig, Forficula auricularia L. sensu lato (Dermaptera: Forficulidae), is a univoltine, resident, omnivorous species and a beneficial predator in pome fruit orchards. Here, three methods were used to investigate pear (Pyrus communis L., Rosaceae) orchard inoculation with European earwig for biocontrol of pear psylla, Cacopsylla pyricola (Foerster) (Hemiptera: Psyllidae), in Washington State, USA. The first method was earwig inoculation experiments. In a first experiment (2019–2020), each of three orchards had one inoculation and one control plot. In a second experiment (2020–2021), there were four inoculation and four control plots in each of the same three orchards. In both experiments, earwigs persisted during the year of inoculation, but earwigs were nearly absent the following season at two orchards that used conventional broad‐spectrum pesticides. At the third orchard, which excluded broad‐spectrum pesticides under an integrated pest management (IPM) program, earwigs became abundant in year two of the second experiment. The second method was case studies. In the first of two case studies, during 2016, 2017, 2022, and 2023, in half of the integrated orchard from above, conventional broad‐spectrum sprays were used. Earwig populations became low in the conventional half. In the second case study, earwigs became abundant after inoculation of an integrated orchard by the grower. Earwigs spread to the edge of the orchard in year two and spilled into a neighboring orchard in years three and four. The third method was an observational study of 36 pear orchards over 5 years. Earwigs were rarely found in conventionally sprayed orchards, and earwigs increased each additional year integrated management was used. The findings suggest conventional pear spray programs in Washington nearly eradicate earwigs, but populations can recover under integrated management with natural dispersal from refuges or with inoculative releases.

Climate change and rising tropospheric ozone concentration are impacting ecosystems in various ways and can influence the volatile-mediated interactions between insects and their host plants. In this study, individuals of the psyllid species Cacopsylla pyri and C. pyrisuga as well as their host plant Pyrus communis were exposed to elevated but naturally occurring ozone concentrations. The effects on the olfactory perception of the insects and the volatile emission of the plants were examined. Ozone exposure affected the olfactory perception of C. pyri and C. pyrisuga. While the perception threshold of hexanal increased in C. pyri, the perception of the tested compounds was not impaired in C. pyrisuga. Behavioural tests with ozone exposed C. pyri revealed an unchanged repellent effect of nonanal, while hexanal and a synthetic volatile blend became repellent to this species. These findings show only minimal direct effects of moderate ozone concentrations on olfactory perception of pear psyllids. In contrast, chemical analysis of the host plant odours showed a dramatic change in the volatile composition during ozone exposure, with a statistically significant decrease of terpenes and an increase of aldehydes and ketones, showing a greater impact of ozone on the emitter than on the receiver in the pear-psyllid system. This study highlights that moderate ozone levels can alter volatile emissions, potentially disrupting host plant location and impacting other insect–plant interactions that depend specifically on volatile-mediated communication.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10886-025-01642-x.

Pear psylla (Cacopsylla pyricola Foerster) is a significant pest of pear trees (Pyrus communis), causing extensive damage to pear orchards through feeding and the secretion of honeydew. A laboratory study was conducted at SKUAST - Kashmir to examine the biology and life cycle of Pear psylla, Cacopsylla pyricola Foerster under controlled conditions (32±2°C, 12:12 photoperiod, and 65±5 % RH). The results revealed that the incubation period lasted for 0.36 days. The insect undergone five nymphal instars, with a total nymphal period of 0.72 days. Adult psyllids exhibited a pre-oviposition period of 0.31 days, followed by an oviposition period of 1.34 days, with fecundity ranging from 400 to 650 eggs/female. Male psyllids lived slightly longer (62.55 days) than females (61.35 days). The study contributes valuable data for better understanding the biology of pear psylla, facilitating more effective pest management strategies in pear-growing regions.

DNA markers are an alternative method for accelerated identification of interested genes and loci at the early stages of ontogenesis, and, consequently, DNA markers are able to intensify the breeding process. This article represents overview of research on the localization of economically useful traits in the pear genome and the development and use of marker-assisted selection (MAS) techniques. At the moment, several traits have been localized in the pear genome, i.e.: resistance to scab European (V. pirina Aderh) and Asian (V. nashicola), black spot (Alternaria alternata (Fr.) Keissler), brown spot (Stemphylium vesicarium), fire blight (Erwinia amylovora), pear psylla (Cacopsylla pyri), pear sawfly (Caliroa cerasi), pear blister mite (Eriophyes pyri), self-incompatibility, dwarf trait. Major genes and loci of quantitative traits (QTLs) of fruits characteristics have also been identified, namely: skin color and rustiness of the fruit, size and weight of the fruit, taste, level of ethylene production, harvest time etc. It should be noted that currently Russian research is limited to the validation and use of MAS methods developed abroad. According to the experience of Japanese scientists, the use of MAS for several key traits has made it possible to triple the efficiency of the breeding process. Despite the currently limited list of MBC methods for pears, the high speed of genomic technologies development promises rapid development of new MAS methods in the future. In combination with new breeding technologies (New Breeding Techniques) based on accelerated flowering, the use of MAS for pears is a promising direction of breeding.

In nature, plant pathogens often rely on insect vectors for transmission. Through long-term evolution, plant pathogens and insect vectors have established a mutually beneficial symbiotic relationship. Fire blight, caused by the Gram-negative bacterium Erwinia amylovora (Eam), poses a significant global threat to apple and pear production due to its rapid dissemination among host plants of the Rosaceae family. Despite evidence of E. amylovora transmission by various insects, the association between this pathogen and the pear psylla Cacopsylla chinensis, a common vector insect in pear orchards, remains unclear. Sampling investigations and qRT-PCR results revealed that C. chinensis, from 11 pear orchards severely affected by fire blight disease in Xinjiang of China, harbored varying levels of this pathogen. Eam-positive females exhibited significantly higher fecundity compared to Eam-negative individuals, displaying accelerated ovarian development and a notable increase in egg production. Further RNAi results revealed that juvenile hormone (JH) receptor methoprene-tolerant (CcMet) and a crucial downstream gene Krüppel-homologue 1 (CcKr-h1) mediated the fecundity improvement of C. chinensis induced by Eam. Additionally, miR-2b, which targets CcKr-h1, was identified as being involved in Eam-induced fecundity enhancement in C. chinensis. This study unveils, for the first time, that Eam colonize and amplify the fecundity of C. chinensis females. Host miR-2b targets CcKr-h1 of the JH signaling pathway to regulate the heightened fecundity of C. chinensis induced by Eam. These findings not only broaden our understanding of the interaction between plant pathogens and insect vectors, but also provide novel strategies for managing fire blight and pear psylla. © 2024 Society of Chemical Industry.