Secondary Pests Research Articles

Presence of a Non-Pest Mite Tarsonemus confusus Ewing (Acari: Tarsonemidae), in Florida Strawberry Fields

This publication aims to benefit growers and Extension agents by increasing awareness of a fungus-feeding mite, Tarsonemus confusus, commonly found in strawberry fields. Tarsonemus confusus may be misidentified as other pest mites. In fact, without help from an expert mite taxonomist, incorrect species identification can be a major concern. Although this mite species typically does not achieve pest status on most crops, an incorrect pest identification may lead to unnecessary application of miticides, triggering a secondary pest outbreak.

Genetic basis of resistance to Cry1Ac in Rachiplusia nu (Lepidoptera: Noctuidae): inheritance mode, cross-resistance patterns and fitness cost.

Rachiplusia nu (Guenée) was historically a secondary soybean pest in Brazil, but a key soybean pest in Argentina. From 2021 onwards, injury caused by R. nu has been reported in soybean that expresses the Cry1Ac toxin from Bacillus thuringiensis (Berliner) in both countries. In this study, we selected resistant and susceptible strains of R. nu to Cry1Ac using Cry1Ac-containing leaf tissue and characterized the inheritance of resistance, cross-resistance patterns and fitness cost. Neonates of the Cry1Ac-resistant strain of R. nu were able to develop on Cry1Ac soybean leaves and emerge as fertile adults, while neonates from the susceptible and heterozygous strains did not survive beyond 10 days. The resistance ratio to Cry1Ac estimated in diet-overlay bioassays in the resistant strain was > 736.92-fold. The inheritance pattern of Cry1Ac resistance in R. nu was characterized as autosomal recessive and monogenic. The Cry1Ac-resistant strain of R. nu also exhibited high resistance to Cry1A.105 (resistance ratio > 159.87-fold), but negligible resistance to Cry2Ab2 (resistance ratio = 1.25-fold). Life history data showed that the resistance to Cry1Ac in R. nu is not associated with a substantial fitness cost. The inheritance pattern of Cry1Ac resistance in R. nu is autosomal recessive, monogenic and not associated with obvious fitness costs. Cross-resistance occurred between Cry1Ac and Cry1A.105 in R. nu but not between Cry1Ac and Cry2Ab2, indicating that Cry1A.105/Cry2Ab2/Cry1Ac soybean is a valuable tool to manage Cry1Ac resistance in R. nu. This is the first study reporting the genetic basis of Cry1Ac resistance in R. nu. © 2024 Society of Chemical Industry. Published by John Wiley & Sons Ltd.

Biology and Management of Eggplant (Solanum melongena L.) Shoot and Fruit Borer: A Review

Eggplant (Solanum melongena Linnaeus) is a vital crop in South Asia, valued for its use in both raw and cooked dishes. However, its cultivation is severely threatened by the eggplant shoot and fruit borer, Leucinodes orbonalis (Guen.), which damages the plant from the seedling stage to harvest. The larval phase of this pest bores into shoots and fruits, potentially causing up to 90% loss and a decline in quality. Farmers often use excessive insecticides to combat L. orbonalis, leading to residue accumulation in food, insecticide resistance, pest resurgence, secondary pest outbreaks, and harm to beneficial organisms and the environment. In South Asia, this pest is the primary threat to eggplant fields, attracting significant research attention. This review paper examines biology, damage and control measures of eggplant shoot and fruit borer including resistant and tolerant varieties, sex pheromone traps, physical and mechanical barriers, biopesticides, biocontrol agents, and cultural and chemical methods, supported by previous studies and research findings. J Bangladesh Agril Univ 22(3): 267-276, 2024

Assessment of Piper longum L. (Piperaceae) leaves toxicity on the adults of Tribolium castaneum (Herbst, 1797) (Coleoptera: Tenebrionidae)

BackgroundNumerous insect pests attack stored grains causing both qualitative and quantitative losses. The most damaging pest that infests dry stored produce is the red flour beetle, Tribolium castaneum, a secondary pest of stored goods. This pest, especially in its adult stage, exhibits resistance to chemical insecticides, thereby rendering the traditional pesticides ineffective in controlling it. Phyto-derivatives, which are strong insecticides and also ecologically benign, have gained interest as non-chemical solutions for controlling this pest. Hence, the objective of this study was to investigate the potential of Piper longum leaf extract insecticidal action as an environmentally benign insecticide for the first time against the adults of T. castaneum. In this study, P. longum leaf ethanol extract was tested against the adults of T. castaneum by petri dish bioassay method. Ad hoc studies to verify significant mortality for the initial confirmation of adulticidal activity were conducted for 24 h at different dosages of 62.5, 125, 250, 500 and 1000 mg/L of P. longum leaf ethanol extract. Thereafter, dosages set at 10, 20, 30 and 40 mg/L for the fractions of P. longum leaf ethanol extract were conducted. Prior to this, the leaf extract of this plant was subjected to column chromatography for fractionation. The fractions tested for adulticidal activity were subjected to gas chromatography–mass spectroscopy.ResultsSignificant adulticidal action with 100% adult mortality was observed in ethanol extract of P. longum leaves. Among the fourteen fractions (F0–F13) obtained tested, only fractions, F5, F10 and F13, demonstrated adulticidal activity, and the remaining fractions displayed poor activity. One hundred per cent morality was noted in T. castaneum adults after 96 h at 40 mg/L in F5 and F10, and in F13 at 20 mg/L, and their respective LD50 values were 17.6, 26.6 and 10.0 mg/L. The fractions F5, F10 and F13 contained fatty acids, viz., hexadecanoic acid, dotriacontane and heptacosane in F5; tetradecanoic acid and nonadecanoic acid in F10; and octadecanoic acid, aspartame and tridecanoic acid in F13, revealed through gas chromatography–mass spectroscopy.ConclusionsThe results of the study showed that P. longum ethanol leaf extract revealed significant adulticidal activity and is a promising toxic agent to the adults of T. castaneum. The fatty acids in the ethanolic leaf extract fractions of P. longum could have caused toxicity to the adults of T. castaneum. According to the current literature survey, this is the first research report on the adulticidal activity of P. longum leaf extracts against the adults of T. castaneum.

Population growth of different stored product species on wheat, barley, and tritordeum

Stored product species can be developed in a variety of stored product grains. In this study, were compare three different grains for their suitability for population growth of primary and secondary stored product insects. In the first series, we evaluated the population growth and damage of Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae), Sitophilus granarius (L.) (Coleoptera: Curculionidae) and Sitophilus oryzae (L.) (Coleoptera: Curculionidae) on whole wheat, barley and tritordeum kernels after 65 days. In the second series, three different percentages of whole and cracked kernels were tested: 100% cracked kernels, 100% whole kernels and 50% cracked +50% whole kernels, for Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae) and Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). The results showed that tritordeum was suitable for the population growth of all species tested. In most of the cases, R. dominica showed higher frass production but S. granarius showed a higher number of damaged kernels. Cracked kernels were preferred by secondary pests than whole kernels and wheat showed the highest progeny production than tritordeum and barley. Overall, commodity, and grain type and percentage of cracked kernels can affect the population growth of stored product insect species. Results of this study showed that stored product insect species can develop in tritordeum and thus should be taken into consideration for further results as may be damaged during storage.

CgSSR marker based trait associations for Sitotroga cerealella (Olivier) resistance in stored paddy rice

Rice is stored for a longer time and many primary and secondary insect pests attack grains, causing both quantitative and qualitative losses. Physicochemical characteristics of grain influence stored grain insect susceptibility and resistance. Identification of gene/Quantitative Trait Loci (QTLs) and introgression in the cultivars would provide the desired solution for varietal resistance against S. cerealella. A group of 80 rice varieties was used for genetic analysis for the identification of candidate genes responsible for Sitotroga cerealella resistance. Heat maps derived from values in the kinship matrix were used to group the varieties into three subpopulations. The largest subpopulation has 34 varieties, while the lowest had 19. The first three principal components (PCs) explained 16, 9, and 6 percent of total variation, respectively, as indicated by the Principal Component Analysis (PCA). The PCA results complemented the heat map results in defining population structure. Genome-wide association mapping can detect marker-trait associations/QTLs in a heterogeneous population of breeding lines, despite population structure and unequal family relatedness. As shown by the Genomic Association and Prediction Integrated Tool (GAPIT) heat map, there are three subpopulations in the association mapping panel. Two cgSSR markers, related to gene SDG725 and FLO2, were linked to the attributes and responsible for conferring resistance against S. cerealella infestation. This is the first report of association and that would help in the development of cultivar with S. cerealella resistance.

BIOTOPE FEATURES OF OILSEED CROPS, BIOECOLOGY OF DEVELOPMENT OF PEST SPECIES, THEIR DAMAGE

Among the types of agricultural crops of Karakalpakstan, sunflower, sesame, soybean, safflower species, which have been growing in the area of cultivation in recent years, are spreading in the biotope, and the types of adapted and secondary pests that damage crops, bioecology of development, dynamics, damage the results of research aimed at determining the contribution of types of external factors that affect the level are included. KEYWORDS: Oil crops, agroclimate, harmful factors, pests, harmfulness, biology, ecology, dynamics, species, distribution areas, entomophages.

Using stink bug migration behavior for physical exclusion.

Stink bugs have become an increasing concern for tree fruit growers due to changing management strategies and the introduction of an invasive species. The use of broad-spectrum insecticides for stink bug control disrupts biological control and leads to secondary pest outbreaks. To seek alternative tactics, we investigated the physical exclusion of native stink bugs with single-wall net barriers at orchard borders. First, stink bug capture on clear sticky panels along orchard edges showed that movement between the native shrub-steppe vegetation and the orchard occurs for much of the growing season instead of the presumed single migration event in August. Most stink bugs were captured between 1 m and 3 m heights, signifying a 4 m exclusion barrier would intercept migrating bugs. We tested large net barriers (4 m × 23 m) constructed of plain netting with or without deltamethrin-infused netting in flaps compared to a no-net control. The capture of target and nontarget arthropods was determined with plastic tarps below the nets or on the open ground of the control. Net barriers did not directly affect stink bug densities in the orchards, although orchard populations were low overall. Barriers did intercept stink bugs, and the addition of deltamethrin flaps enhanced stink bug mortality but at the price of nontarget arthropod mortality. Our results indicate that stink bug management efforts should focus earlier in the growing season and given the long period of migration, barriers are a more sustainable way of slowing movement into the orchard than the current sole reliance on chemical control.

An exploratory analysis of the structure of tetranychid and phytoseiid assemblages in walnut orchards in California.

Spider mites were considered secondary pests of walnut production in California, under the control of phytoseiid predators. Due to increased importance as walnut pests in recent decades there is renewed interest in the structure and function of the associated phytoseiid assemblage. In this study we report the results from a 3 year survey of the tetranychid and phytoseiid assemblages in walnut orchards in the Central Valley of California. The survey was conducted to determine the range and dominance of web-spinning Tetranychus species present, to investigate the species richness and dominance of the phytoseiid species present, and to explore whether patterns of variation in the relative abundance of phytoseiid species could be explained by one or more explanatory variables. Tetranychus urticae was the dominant spider mite in all growing regions and years with T. pacificus and T. turkestani also present in orchards in the southern San Joaquin Valley. Phytoseiid species richness declined with latitude among the three walnut growing regions and of the 13 species found Amblyseius similoides, Euseius stipulatus, Galendromus occidentalis and Typhlodromus caudiglans were the most abundant and widespread species present. Mean proportional abundance significantly increased from early (mid May-July) to late (August-mid October) season and from southern to northern growing regions for Type II and IV predators, but significantly decreased from early to late season and from southern to northern growing regions for Type III predators. The mean proportional abundance of Type II predators, particularly G. occidentalis, significantly increased and that of Type III predators significantly decreased with mean Tetranychus density in individual orchards. The current survey provides a more in-depth analysis of mite assemblages in walnut orchards in California and can be used to better inform adaptive management strategies for integrated mite management in the future.

Why does identification matter? Thrips species (Thysanoptera: Thripidae) found in soybean in southern Brazil show great geographical and interspecific variation in susceptibility to insecticides

Thrips have historically been considered secondary soybean pests in Brazil and neighboring countries. However, since the 2010s they have gained importance in soybean in central and northern Brazil. From 2017 onwards, high infestations of thrips have also been detected in soybean in southern Brazil. Here, we collected and identified thrips species from soybean fields in southern Brazil throughout the 2022/2023 season and conducted laboratory bioassays to assess their susceptibility to selected insecticides. Thrips were exposed to the field concentrations of selected insecticides in leaf-dip bioassays using soybean leaves. Our results indicated that Frankliniella schultzei (Trybom, 1910) and Caliothrips phaseoli (Hood, 1912) are the major thrips species found in soybean in southern Brazil. These species exhibited high mortality and relatively low geographic and interspecific variation in susceptibility to the field concentrations of spinetoram, methomyl, spinetoram + methoxyfenozide and profenofos + cypermethrin. In general, most populations of C. phaseoli were more susceptible to acephate, chlorfenapyr and abamectin than F. schultzei, whereas bifenthrin + carbosulfan showed high lethality against most populations of F. schultzei, however, both species had wide geographic variation in susceptibility to these chemistries. In contrast, populations of both species have low mortality when exposed to the field concentrations of imidacloprid, lambda-cyhalothrin and lambda-cyhalothrin + sulfoxaflor. In summary, our study documents significant variations in the susceptibility of F. schultzei and C. phaseoli to selected insecticides, both among species and among geographical areas across southern Brazil. These results highlight the importance of species identification for the effective control of thrips in soybean in Brazil and other South American countries.

Biological Characteristics and Thermal Requirements of Telenomus podisi and Trissolcus basalis (Hymenoptera: Scelionidae) in Fresh and Cryopreserved Eggs of Euschistus heros and Nezara viridula (Hemiptera: Pentatomidae)

Brazil is one of the largest producers of pulses globally, and soybean ranks highly in terms of production. However, pests increase crop production costs and affect oilseed production and quality. Pests are primarily controlled by chemicals, leading to changes in insect pest populations. For example, secondary pests can become primary pests because of the selection of resistant insects and the elimination of natural enemies. Farmers have widely accepted biological control because of its high control efficacy and low environmental contamination risk. Two successful biological control programs in soybean used Telenomus podisi Ashmead (Hymenoptera: Platygastridae) to manage the Neotropical brown stink bug, Euschistus heros (Fabricius) (Hemiptera: Pentatomidae), and Trissolcus basalis (Wollaston, 1858) (Hymenoptera: Scelionidae) to manage the southern green stink bug, Nezara viridula (Linnaeus) (Hemiptera: Pentatomidae), when these pests were the most abundant in soybean-producing regions. To release parasitoids, rearing protocols must be developed in order to optimize production. This study evaluated the effect of temperature on the biological characteristics of T. podisi and T. basalis when fresh or frozen E. heros eggs were provided. Fifty fresh or previously frozen eggs were placed with parasitoids for 24 h in a climate chamber (25 ± 1 °C, 70 ± 10% RH, and 14-h photophase). At the end of this period, the eggs were transferred to other chambers and maintained at different temperatures (19, 22, 25, 28, 31, and 34 ± 1 °C, 70 ± 10% RH, with a 14-h photoperiod). The number of emerging adults from eggs parasitized by T. basalis was lower than that from eggs parasitized by T. podisi. Differences in T. basalis and T. podisi parasitism were observed depending on whether the E. heros eggs were frozen or fresh, but neither development nor emergence were affected. The duration of egg–adult development and the longevity of the two parasitoids were inversely proportional to the temperature increase. The sex ratio of T. basalis and T. podisi progeny was not affected by different temperatures or by the use of frozen or fresh eggs. The estimated number of both parasitoids’ generations corresponded with temperature, reaching 14–15 generations/cycle of soybean for Rio Verde, GO, and 12–14 generations/cycle for Barreiras, BA. Given these characteristics, we conclude that a biological control program using T. podisi can benefit large areas of soybean production by controlling the eggs of phytophagous bugs in soybean crops.

Ophiostomatalean fungi associated with Polygraphus bark beetles in the Qinghai-Tibet Plateau, China.

Climate change has exacerbated outbreaks of forest pests worldwide. In recent years, bark beetles have caused significant damage to coniferous forests of the Northern Hemisphere. Polygraphus bark beetles are widely distributed secondary pests. Recently, tree mortality caused by these beetles on the Qinghai-Tibet Plateau has been increasing; however, few studies have focused on their fungal associations. In the present study, we explored the diversity of ophiostomatalean fungi associated with these beetles on the north-eastern and southern Qinghai-Tibet Plateau. We isolated 442 ophiostomatalean strains from adult beetles and their fresh galleries, specifically targeting Polygraphuspoligraphus and Polygraphusrudis infesting Piceacrassifolia and/or Pinusgriffithii. Based on phylogenetic and morphological features, we assigned the 442 strains to 16 species belonging to Grosmannia spp., Leptographium spp. and Ophiostoma spp. Amongst these, Ophiostomamaixiuense and Ophiostomabicolor were the most frequently isolated species, accounting for 20.8% and 18.1% of the total number of ophiostomatalean assemblages, respectively. By comparing their fungal communities, we found that the different patterns of fungal assemblages of bark beetles from the north-eastern and southern Qinghai-Tibet Plateau may be influenced by biogeographic barriers and host tree species. The results of this study enhance our understanding of bark beetle fungal assemblages, especially Polygraphus, on the Qinghai-Tibet Plateau, with implications for forest management under changing climate.

The invasive ambrosia beetle, Gnathotrichus materiarius (Coleoptera: Curculionidae), in Central Europe

Abstract Gnathotrichus materiarius Fitch, 1858 is an invasive bark beetle that colonizes conifers and has spread widely in Europe. The beetle was introduced from North America to Western Europe, where it was first detected in France in 1933. In countries of Western and Northern Europe, the first detections were found at ports or airports, which probably served as sources of further spread. Gnathotrichus materiarius spread eastward to the Czech Republic and other countries in Central Europe from Germany and Poland and spread northward from Italy to Slovenia. The presence of wilting spruces, outbreaks dominated by Ips typographus Linnaeus, 1758, and the subsequent transport of timber have probably accelerated the spread of G. materiarius. It is possible that G. materiarius was imported with timber to Austria, the Czech Republic, and Poland. Although G. materiarius has been present in Europe for almost 100 yr, and even though its host trees include Picea and Pinus spp., which are abundant in Central European forests, no significant damage caused by this beetle has been detected or reported. Gnathotrichus materiarius is a typical secondary pest in that it multiplies on decaying trees or trees already infested and killed by other bark beetle species. It has 2 generations a year in Central Europe. The beetles of G. materiarius occur the whole year, but the flight of adults starts in early May and the offspring beetles emerge in mid-July. The adults of F2 generation overwinter in wood. The best method for monitoring and detecting the presence of G. materiarius is the use of ethanol-baited traps.

Mathematical modeling of the parasitism and hyperparasitism increase on <i>Halyomorpha halys</i> eggs in a five-year survey in Northern Italy

<p>The invasive stink bug <italic>Halyomorpha halys</italic> has become an important pest of many crops, causing severe economic losses to farmers. Control of the pest mainly relies on multiple applications of broad-spectrum insecticides, undermining the integrated pest management programs and causing secondary pest outbreaks. In the native area, egg parasitoids are the main natural enemies of <italic>H. halys</italic>, among which <italic>Trissolcus japonicus</italic> is considered the predominant species. In Italy, adventive populations of <italic>T. japonicus</italic> and <italic>Trissolcus mitsukurii</italic>, another egg parasitoid of <italic>H. halys</italic> in Japan, have established themselves. These two species, together with the indigenous <italic>Anastatus bifasciatus</italic>, are capable of attacking the eggs of the exotic host. Focusing on the situation in Northern Italy, where also the hyperparasitoid <italic>Acroclisoides sinicus</italic> is present, a discrete-time model is developed for the simulation of the pest evolution. It is based on actual field data collected over a timespan of five years. The simulations indicate that egg parasitoid by themselves do not suppress populations to non-pest levels, but can play an important role in reducing their impact. Both the data from the five-year surveys and those available in the literature are used in the model. It has some limitations in the fact that climatic conditions were not considered, while more accurate simulations could be performed with additional collection of field data, which at the moment are based on partial field observations not sampled at the same sites.</p>

Contact toxicity and proximate effect of fipronil on insect pest and predatory ant community structure in cocoa agro-ecosystem

Although usage persists in some countries, fipronil is banned or restricted in many others. Prior to its ban on cocoa in Ghana, concerns about its effect on non-target insects and secondary outbreak of Anomis leona were conflicting. This study, which predates the ban, assessed the toxicity and the short-term effect of fipronil on specific insect community structure in the cocoa agro-ecosystem alongside bifenthrin and a non-insecticide control. Although the insecticides induced a high mortality (90-100%) on the target (mirid: Sahlbergella singularis, stink bug: Bathycoelia thalassina and coreid bug: Pseudotheraptus devastans) and non-target (ants: Oecophylla longinoda, Crematogaster africana, Pheidole megacephala and Camponotus consobrinus) insects, the knockdown to fipronil was very low compared to bifenthrin. On the field, fipronil was more detrimental to the ants. Insecticide-treated plots recorded relatively lower post-treatment pest diversity compared to the control, except the last sampling month while ant abundance, richness and diversity were lowest on the fipronil-treated plots at the end of the study period. This study demonstrates that although fipronil was effective against pests and did not result in acute secondary pest outbreak, it was harmful to the ants. This effect could potentially be replicated on these ant species in other cropping systems where the insecticide is used, adversely affecting ecosystem service delivery. Hence, research on its impact on non-target organisms in other cropping systems is needed to regulate and monitor its use.

Hybrid Bt cotton is failing in India: cautions for Africa

This paper reviews the ongoing failure of hybrid transgenic Bt (Bacillus thuringiensis) cotton unique to India. The underlying cause for this failure is the high cost of hybrid seed that imposes a suboptimal long-season low plant density system that limits yield potential and has associated elevated levels of late-season pests. Indian hybrid Bt cotton production is further complicated by the development of resistance to Bt toxins in the key pest, the native pink bollworm (Pectinophora gossypiella Saunders, PBW), resulting in increased insecticide use that induces ecological disruption and outbreaks of highly destructive secondary pests. Rainfed cotton production uncertainty is further exacerbated by the variable monsoon rains. While hybrid cotton produces fertile seed, the resulting plant phenotypes are highly variable preventing farmers from replanting saved seed, forcing them to buy seed yearly (i.e., market capture), and effectively protecting industry Intellectual Property Rights (IPRs). The lessons gained from the ongoing market failure of hybrid Bt cotton in India are of utmost importance to its proposed introduction to Africa where, similar to India, cotton is grown mainly in poor rainfed smallholder family farms, and hence similar private–corporate conflicts of interest will occur. Holistic field agroecological studies and weather-driven mechanistic analyses are suggested to help foresee ecological and economic challenges in cotton production in Africa.High-density short-season (HD-SS) non-hybrid non-genetically modified irrigated and rainfed cottons are viable alternatives for India that can potentially produce double the yields of the current low-density hybrid system.

Hail netting excludes key insect pests and protects from fruit damage in a commercial Minnesota apple orchard.

Exclusion netting in some European and North American apple (Malus domestica Borkhausen, Rosaceae, Rosales) orchards has been documented to be an effective method of control for multiple insect pest species. By minimizing reliance on insecticides, these orchards have reduced costs, risks to the environment and non-target species, and reduced the risk of insecticide resistance. This study examined the use of commercially available hail netting (DrapeNet®; Prosser, WA) as a pest exclusion strategy under conditions in Minnesota, USA. In 2021 and 2022, we assessed the efficacy of hail netting as a tool for pest suppression in orchards by monitoring pest species in netted and open plots crossed with and without insecticide applications. Our findings show that both of the major pest species in Minnesota, the codling moth (Cydia pomonella L.; Lepidoptera: Tortricidae) and the apple maggot (Rhagoletis pomonella Walsh; Diptera: Tephritidae), were significantly reduced inside the netting compared to open plots by 94% and 96%, respectively. For a secondary pest, the red-banded leafroller (Argyrotaenia velutinana Walker; Lepidoptera: Tortricidae), moth populations were reduced by 56%. We also found that insecticide application alone did not significantly reduce pest pressure in these species. Additionally, we investigated the subsequent effects of hail netting on fruit quality and yield. The use of hail netting and insecticide application resulted in significantly higher proportions of high-quality fruit at harvest. However, netting did not significantly influence yield. These findings suggest that hail netting can be used to control Midwest apple insect pests with limited insecticide applications while maintaining high fruit quality.

The green shield bug, Palomena prasina, and the red-legged shield bug, Pentatoma rufipes, two secondary pests of French hazelnuts

The green shield bug, <i>Palomena prasina,</i> and the red-legged shield bug, <i>Pentatoma rufipes</i>, two secondary pests of French hazelnuts

Microscopic morphology and distribution of the antennal sensilla in the double-spined bark beetle, Ips duplicatus (Coleoptera: Curculionidae).

The double-spined spruce bark beetle, Ips duplicatus, has become an infamous secondary pest of Norway spruce, causing extensive ecological and economic destruction in many Central European countries. Antennae are the primary olfactory organs that play a fundamental role in insect-host chemical communication; therefore, understanding morphology is crucial before conducting electrophysiological investigations. Here, we present our analysis of sensilla types on the antennal surface of I. duplicatus for the first time, using high-resolution-scanning electron microscopy. We studied the external morphological characteristics of antennae and the types, numbers, and distribution of the antennal sensilla in males and females. Our results revealed the presence of five different types of morphologically distinct sensilla: sensilla chaetica, sensilla basiconica, sensilla trichodea, sensilla coeloconica, and Böhm's sensilla. We observed two subtypes of sensilla chaetica (SChI and SChII), four subtypes of sensilla basiconica (SBI, SBII, SBIII, and SBIV), three subtypes of sensilla trichodea (STrII, STrIII, and STrIV) and two subtypes of sensilla coeloconica (SCoI and SCoII), respectively in I. duplicatus males and females. Minor differences in length and numbers between the sexes for some sensilla types were found. Distribution maps for different sensillar types were constructed, and specific areas for the respective sensilla were found. Possible functions of observed sensilla types are discussed. The present study provides a basis for future electrophysiological studies to understand how I. duplicatus detects ecologically important olfactory cues. RESEARCH HIGHLIGHTS: • The first report of morphology and distribution pattern of the antennal sensilla in Ips duplicatus is discussed. • A total of 6 main types and 11 antennal sensilla subtypes were observed in male and female Ips duplicatus. • Minor sex-specific differences were seen in the length and numbers in several sensilla types.

Features and dynamics of species composition of entomoacarosystems in plum orchards

The long-term analysis of the entomocomplex of plum orchards, carried out in Krasnodar Territory, revealed variations in the quantitative composition of entomofauna of harmful species and the level of their harmfulness. It was established that, in the period from 2005 to 2021, the rotation of dominant and secondary species occurred. The main species included plum Grapholitha funebrana Treitschke and oriental Grapholitha molesta Busck fruit moths, plum black Haploca minuta Christ. and yellow Hoplocampa flava L. sawflies, plum aphid Hyalopterus pruni Geoffr. and twospotted spider mite Tetranychus urticae Koch. Associated species included plum gall Acalitus phloeocoptes (Nal.) and hawthorn Tetranuchus viennensis Zacher. mites, fruit-tree Tibicina haematodes Scopoli and citrus flatid Metcalfa pruinosa (Say) planthoppers and leaf roller moths of Tortricidae family. The group characterised by a limited distribution area includes the Californian Quadraspidiotus perniciosus Comst. and Turanian Diaspidiotus prunorum Laing. scales, plum Sphaerolecanium prunastri Fonsc and European brown Parthenolecanium corni Bouche. scales, seed wasps Eurytoma amygdali End., brown marmorated stinkbug Halyomorpha halys (Stål) and secondary insects (unequal bark beetle Xyleborus dispar F., fruit tree bark beetle Scolytus rugulosus (P.W.J. Müller), wood leopard moth Zeuzera pyrina L). When considering the structure formation of phytophage complex according to phylogenetic specialization, taking into account trophic relationships, it was established that the proportion of polyphages is 2.5 times higher than that of oligophages and 8.5 times higher than that of monophages from the total number of registered pest species. In the past decade, a reduction of pesticide load in plum agrocenoses has been observed due to the wider use of agrotechnical methods and the inclusion of bioregulatory and biological insecticides into protection systems, which contributed to the preservation and increase of beneficial fauna. Entomophages constitute 7–10% of the total number of entomoacrocenosis dominated by Hymenoptera and Coleoptera classes and mites of Acari subclass. The long-term monitoring of species composition, rotation of dominant and secondary pest species and entomophages, variations in their number and harmfulness, seasonal dynamics, trophic relationships of plum entomoacrocenosis under varying environmental conditions and increasing intensification of agricultural production expand the possibility of phytosanitary optimisation strategy of perennial agrocenoses in the south of Russia. This contributes to the preservation of regional biodiversity, as well as to the stable production of high-quality ecologically safe products with minimal negative impact on the environment.