Distribution Of Aphids Research Articles

A contribution to the aphid fauna (Homoptera, Aphidinea) of the Republic of Dagestan (the Russian Federation), with descriptions of three new species, redescription of Macrosiphum pulcherimum Nevsky, 1928, and descriptions of previously unknown morphs of three species.

An updated aphid (Homoptera, Aphidinea) check-list of the Republic of Dagestan (the Russian Federation) is presented, it includes 125 species and 2 subspecies. Three new aphid species are described here: Aphis dagestanica sp. nov. based on apterous viviparous females, oviparous females and apterous male, living on Caucasalia parviflora (Asteraceae), Aphis epilobiphaga sp. nov. based on apterous viviparous females, living on Epilobium colchicum (Onagraceae) and Aphis oxalicola sp. nov. based on apterous viviparous females, living on Oxalis stricta (Oxalydaceae). Redescription of Macrosiphum pulcherimum Nevsky, 1928 based on apterous viviparous females are given, a lectotype is designated and data provided on the distribution and biology of this species. Previously unknown males and oviparous females of Aphis leontodontis (Börner, 1950) and Brachyunguis zygophylli (Nevsky, 1928) and oviparous females of Aphis apocynicola Holman, 1992, are described. Notes about the distribution and biology of aphids recorded in Dagestan and on the completeness of the list are given.

Current knowledge and breeding strategies for management of aphid-transmitted viruses of pepper (Capsicum spp.) in Africa.

Aphid-transmitted viruses cause significant losses in pepper production worldwide, negatively affecting yield and quality. The emergence of new aphid-transmitted viruses or development of variants as well as the occurrence in mixed infections make management a challenge. Here, we overview the current status of the distribution, incidence and phylogeny of aphids and the viruses they transmit in pepper in Africa; outline the available genetic resources, including sources of resistance, resistance genes and molecular markers; and discuss the recent advances in understanding the genetic basis of resistance to the predominant African viruses infecting pepper. Pepper veinal mottle virus (PVMV; Potyvirus); Potato virus Y (PVY; Potyvirus), Chili veinal mottle virus (ChiVMV; Potyvirus), Cucumber mosaic virus (CMV; Cucumovirus) and Pepper veins yellow virus (PeVYV; Polerovirus) have been reported to be the most widespread and devastating aphid-transmitted viruses infecting pepper across Africa. Co-infection or mixed infection between aphid-transmitted viruses has been detected and the interrelationship between viruses that co-infect chili peppers is poorly understood. Establishing and evaluating existing and new diversity sets with more genetic diversity is an important component of developing host resistance and implementing integrated management strategies. However, more work needs to be done to characterize the aphid-transmitted viral strains across Africa and understand their phylogeny in order to develop more durable host resistance. In addition, a limited number of QTLs associated with resistance to the aphid-transmitted virus have been reported and QTL data are only available for PVY, ChiVMV and CMV mainly against European and Asian strains, although PVMV is likely the most important aphid-transmitted viral disease in Africa. There is a need to identify germplasm resources with resistance against various aphid-transmitted virus strains, and subsequent pyramiding of the resistance using marker-assisted selection could be an effective strategy. The recent advances in understanding the genetic basis of the resistance to the virus and the new breeding techniques that can be leveraged to accelerate breeding for aphid-transmitted virus in pepper are proposed as strategies to more efficiently develop resistant cultivars. The deployment of multi-genetic resistances in pepper is an effective and desirable method of managing viral-diseases in Africa and limit losses for farmers in a sustainable manner.

Evaluating climate change scenarios on global pea aphid habitat suitability using species distribution models

The global threat of invasive alien species (IAS) being introduced into new habitats is concerning, particularly in agricultural crops as invasive insect species are continuing to expand their distribution through anthropogenic activities and climate changes. Pea aphids (Acyrthosiphon pisum Harris) are an economic threat to numerous legume crops as they can reproduce parthenogenetically, damage crops directly, and vector over 30 plant viruses as the insect's distribution continues to spread. There are no existing pea aphid-specific risk maps that identify the habitat suitability of pea aphids at either a regional or global scale. Here, we used Species Distribution Models (SDMs) to evaluate which climatic variables influence pea aphid distribution, identify regions of potential distribution, and analyze the global distribution of pea aphids under current and future climate change scenarios (SSP 126, 245, and 370) by utilizing presence-only SDMs based on Maximum Entropy (MaxEnt). The modeling results indicate suitable conditions are relevant for pea aphid establishment in six out of seven continents, with significant range expansion in western Canada, the United States of America, and across Europe. We identified human influence to be the most prominent predictor in determining the distribution of pea aphids, supporting the fact that invasive species distributions are heavily impacted by human activities.

Species and population distribution of plant aphids in agrobiocenose of southeast regions of Uzbekistan

In the years 2022 and 2023, comprehensive investigations and experiments were conducted in the Sardoba district of the Syrdarya region. These efforts aimed to address the threat posed by plant aphids to cotton, vegetable, and rice crops. In 2022, scientific interventions were carried out across a total area of 130 hectares, followed by an expansion to 180 hectares in 2023. The scientific endeavors were centered on identifying and systematically analyzing the types of pests prevalent in the vegetable agrobiocenosis of the Syrdarya region. The research findings revealed the widespread presence of various pests, including moths, white butterflies, spider mites, and plant aphids. Among these, special attention was directed towards studying members of the Aphididae family within the Homoptera order. Moreover, the investigation extended to identifying their natural predators, known as entomophagous species. Specifically, entomophagous species such as Coccinella septempunctata, Chrysopa carnea, and Lysiphlebus fabarum were identified as playing significant roles in regulating the population of plant aphids and maintaining ecological balance. These genera act as natural enemies of aphids, helping to control their numbers and prevent widespread infestations that could damage agricultural crops. This holistic approach not only mitigates the negative impacts of pest outbreaks but also fosters biodiversity and ecosystem resilience. The findings of these investigations provide valuable insights into the ecological dynamics of agricultural ecosystems in the Syrdarya region, Uzbekistan and contribute to the development of integrated pest management practices.

The Spatiotemporal Distribution, Abundance, and Seasonal Dynamics of Cotton-Infesting Aphids in the Southern U.S.

Cotton leafroll dwarf virus (CLRDV) is an emerging aphid-borne pathogen infecting cotton, Gossypium hirsutum L., in the southern United States (U.S.). The cotton aphid, Aphis gossypii Glover, infests cotton annually and is the only known vector to transmit CLRDV to cotton. Seven other species have been reported to feed on, but not often infest, cotton: Protaphis middletonii Thomas, Aphis craccivora Koch, Aphis fabae Scopoli, Macrosiphum euphorbiae Thomas, Myzus persicae Sulzer, Rhopalosiphum rufiabdominale Sasaki, and Smynthurodes betae Westwood. These seven have not been studied in cotton, but due to their potential epidemiological importance, an understanding of the intra- and inter-annual variations of these species is needed. In 2020 and 2021, aphids were monitored from North Carolina to Texas using pan traps around cotton fields. All of the species known to infest cotton, excluding A. fabae, were detected in this study. Protaphis middletonii and A. gossypii were the most abundant species identified. The five other species of aphids captured were consistently low throughout the study and, with the exception of R. rufiabdominale, were not detected at all locations. The abundance, distribution, and seasonal dynamics of cotton-infesting aphids across the southern U.S. are discussed.

Spatial distribution of cereal aphids determines their abundance and population density in winter wheat stands

AbstractThe numbers per tiller (abundance) and per unit area of ground (population density) of the dominant cereal aphids in winter wheat crops, Sitobion avenae (Fabricius) and Metopolophium dirhodum (Walker) (Hemiptera: Aphididae) were recorded from 2000–2015. The results were used to test the hypothesis that at the population peak and 4 weeks previously, the population density of aphids in winter wheat crops (Triticum aestivum L., Poaceae) is uniformly distributed with respect to surface area and, as a result, their abundance is high in sparse stands (SPA) where the colonizing aphids are scattered among a small number of tillers (ca. 80 m−2), and low in dense stands (DEN) where they are scattered among a larger number of tillers (ca. 440 m−2). This prediction was verified for S. avenae, the population density of which did not significantly differ between SPA and DEN stands throughout this period. This species feeds mainly on the ears, whose nutritional quality for aphids varies little with crop density and during the course of ripening. In contrast and contrary to our prediction, the population density of M. dirhodum increased throughout this period more rapidly in SPA than in DEN stands. This species lives on leaves whose quality is better and remain present for longer during the course of ripening of the crop in SPA than DEN stands. The abundance of both species was higher in SPA than in DEN stands. Greater direct damage to cereal crops can be expected when using technologies and cultivars of winter wheat that need to be planted sparsely.

Deep learning-based detection of aphid colonies on plants from a reconstructed Brassica image dataset

Plant pathogenic colony-forming aphids are serious pests of agricultural crops. Most aphid species develop colonies, which are several to many aphids that are functionally organized to extract food from plants. Early and efficient detection of aphid colonies enables the implementation of control measures to reduce crop damage. Aphid colonies exhibit different shapes, sizes, and numbers of individuals, and their distribution makes it hard to detect them correctly. This paper investigates machine learning-based aphid colony detection from imagery. To the best of our knowledge, it is the first study that uses artificial intelligence-based computing algorithms to detect aphid colonies from images. As such, no aphid colony image dataset is currently available publicly. To mitigate this, we have relabelled an existing insect and pest dataset and repurposed it as an aphid colony dataset (AphColDat). For labelling, first, we automatically identify the regions of interest for colonies based on the locations and distributions of aphids. A novel bounding box merging technique is proposed to generate regions potential colony boxes. These colony boxes are a collection of single or overlapping aphid boxes that co-locate together in a colony. Once the dataset is constructed, a convolutional neural network (CNN)-based binary classification algorithm is applied to the images to create AphColDat. This paper evaluates several object detecting deep learning models on the newly developed dataset. The results demonstrate mean average precisions (mAP) of 56.9%, 53.4%, 53.1%, and 48.7% respectively by Faster R-CNN, SSD, YOLOv3, and EfficientNet. In terms of average detection speed (computational time), SSD and EfficientNet are faster than Faster R-CNN and YOLOv3.

Comparison of Droplet Distribution and Control Effect of Wheat Aphids under Different Operation Parameters of the Crop Protection UAV in the Wheat Flowering Stage

Aphid is one of the main insect pests of wheat in the flowering stage, so timely and effective control of wheat aphids plays an important role in ensuring wheat yield. The crop protection Unmanned Aerial Vehicle (UAV) is widely used in the control of wheat pests and diseases nowadays. In order to screen out the suitable operation parameters of the crop protection UAV to control the wheat aphids, this study conducted wheat aphid distribution investigation tests and droplet distribution tests. With the P20 electric four-rotor crop protection UAV (Guangzhou Jifei Technology Co., Ltd., Guangzhou, China) as the test equipment, four levels of flight speed (FS: 3, 4, 5, 6 m/s) and three levels of flight height (FH: 1.5, 2, 2.5 m) were combined as operation parameters, tests were carried out to compare the density and uniformity of droplet coverage, and the wheat aphid control tests were carried out by using the optimized operation parameters. The results of the wheat aphid distribution investigation test showed that aphids mainly distributed in the lower layer of the wheat plant canopy, accounting for more than 90.61%. The results of the droplet distribution test showed that with the increase in FS and FH, the coverage density and the droplet distribution uniformity in the upper and lower layers of wheat showed a downward trend under the condition of considering the boundary overlap of spraying width (SW) in multi-routes. Through the comparison of operation efficiency and droplet distribution quality, two combinations of parameters A1 (FS: 3 m/s, FH: 1.5 m) and B1 (FS: 4 m/s, FH: 1.5 m) were selected for the aphid control effect test. The results of the control test showed that the average control effect of A1 (92.05%) on aphids was 10.3% higher than that of B1 (81.75%) 7 days after pesticide application, which indicated that improving the droplet distribution uniformity in the lower layer of wheat could significantly improve the control effect of aphids. This study result could provide reference for the same type of crop protection UAV to control the same type of wheat diseases and insect pests in the same growing stage.

INVASIVE ALIEN APHIDS (HEMIPTERA: APHIDOMORPHA) OF TURKEY

This study aims to reveal important results on the relationship and the variation between the number of aphid species and the number of invasive alien aphid species in Turkey, the taxonomic diversity of invasive alien aphids, the distribution in Turkey and the regions of origin of invasive alien aphids. The comprehensive study present the presence of 60 invasive alien aphid species belonging to 35 genus from the Aphidomorpha suborder (Hemiptera) recorded in Turkey between 1903 and 2021. It was determined that the invasive alien aphid constitute about 10% of the aphid fauna of Turkey including 592 species belonging to 148 genera. Based on 119 years of data, the average introduction rate of invasive alien aphids into the aphid fauna of Turkey was calculated as 0.51 species per year. Also, it was determined that the invasive alien aphids are distributed in 60 of 81 provinces in Turkey. This study is the first comprehensive research including important data on invasive alien aphids in Turkey. As a result, it is thought that more local and territorial studies should be carried out in order to determine detally the current status and distribution of invasive alien aphids in Turkey.

Species Composition and Distribution of the Vector Aphids of PVY and PLRV in India

Species Composition and Distribution of the Vector Aphids of PVY and PLRV in India

<p><strong>Spatial distribution and sequential sampling of aphid and their natural enemies on wheat</strong></p>

Although many pests attack wheat, the damage due to wheat aphids has been on rise due to climate change phenomenon. Population of aphids increases during February to March and so the ladybird beetles to devour on aphids. With the aim of facilitating conservation of ladybird beetles, predator conditioned sampling plans were worked out. Wheat aphids, Rhopalosiphum padi L. and Sitobion avenae F. were observed infesting wheat. Major predatory coccinellid beetles, Cheilomenes sexmaculata (Fabricius) and Coccinella septempunctata (Linnaeus) were also found feeding on the wheat aphids. Spatial distribution of mixed population of the aphids and coccinellid beetles was analyzed using variance-mean ratio and regression models such as Taylor’s power law and Iwao’s mean crowding regression. The aphids and its predatory beetles were counted at different crop age. The mean population for wheat aphid was 7.88/plant and 0.72/ plant at 75 and 106 days after sowing (DAS), respectively. Variance-mean ratio indicated regular to aggregated distribution of aphids on the crop. Taylor’s power law aggregation parameter (b = 2.62) and density contagiousness co-efficient (β = 1.20) of Iwao’s mean crowding regression also revealed aggregated distribution of the wheat aphids. The mean population of coccinellid beetles varied from 0.72 to 1.43/plant during 68 to 100 DAS. Taylor’s power law aggregation parameter (b = 3.64) and density contagiousness co-efficient (β = 2.09) of Iwao’s mean crowding regression revealed aggregated distribution of the predators on the wheat crop. Sequential sampling plans were developed for wheat aphid management with and without predator’s effect through Taylor’s power law and Iwao’s mean crowding regression. Inclusion of predator effect in the regression models increased aphid population levels which necessitates need for management measures at higher population levels. Thus, the sequential sampling plans with predator effect are useful in avoiding unnecessary pesticide application on wheat crop for the aphid management.

Turunçgil yaprakbitleri (Hemiptera: Aphididae): bulaşıklık oranları, popülasyon dalgalanmaları, konukçu bitki ve yaş tercihleri

Citrus plantations are suffered from many different pest species in East Mediterranean Region. Among them, aphids (Hemiptera: Aphididae) are one of the important groups. Some species such as Aphis gossypii Glover, Aphis spiraecola Patch, Aphis craccivora Koch, Aphis (Toxoptera) aurantii (Boyer de Fanscolombe) and Myzus (Nectarosiphon) persicae (Sulzer) (Hemiptera: Aphididae) cause harm especially young citrus orchards. This study aimed to investigate regional distribution, seasonal fluctuation, host and host age preferences within citrus species of these aphid species in 15 sub-regions from Adana, Hatay, Osmaniye and Mersin between 2007 and 2009. While the mandarin was more preferred than other citrus species, grapefruit was the least preferred citrus species among in all the three provinces. Among the citrus species in the Mersin region, A. spiraecola was the most common in lemons, while A. (T.) aurantii preferred mandarin compare to others. In Adana and Hatay regions, mandarin was the most preferred citrus species for all aphid species except M. (N.) persicae. Aphid preferences depending on the age showed differences in citrus age scale by region. A. (T.) aurantii, on the other hand, had the highest rate of presence between the ages of 11-20 in Hatay and between the ages 21-40 in Mersin. The prevalence of citrus varieties in Adana and Hatay parallelly affected the distribution of aphids. However, A. spiraecola was dominant aphid species on the lemon. Adana, which has a richer flora compared to Mersin and Hatay regions, has been determined the highest aphid density in different species. The fact that Aphis goosypii and A. spiraecola create up to 30-40% infections rate in citrus orchards not only in spring, but also in July, and intense again in autumn have made these pests harmful for four seasons.

Diversity and distribution of gall-forming aphids of the genus Pemphigus (Sternorrhyncha: Aphididae, Pemphigini) in Eastern Siberia

We reviewed the diversity and distribution of the gall-forming aphids of the genus Pemphigus developing on poplars in Eastern Siberia. As a result, the checklist of this group was compiled comprising 13 species distributed in this macroregion that accounts about 29% of the world's known poplar-feeding Pemphigus species. Biogeographical and host plant data are provided for all listed species. Pemphigus birimatus Ivanovskaja, Pem. laurifoliae Dolgova, and Pem. matsumurai Monzen were documented for the first time in the Republic of Tuva. In addition, the latter two species were also discovered in the Republic of Buryatia and Zabaikalskii Krai, respectively. Two poplars Populus × sibirica and Pop. laurifolia were recorded as novel hosts for 3 Pemphigus species. The origin of Pem. passeki Börner, Pem. spyrothecae Passerini, and Pem. microsetosus Aoki in Eastern Siberia remains unclear. Four species Pem. populi Courchet, Pem. bursarius (Linnaeus), Pem. matsumurai, and Pem. spyrothecae Lichtenstein cause noticeable damage to poplars in man-made plantations.

Spatial distribution of aphids in the canopy of a temperate forest: where can they be found?

Abstract Temperate forest canopies support a high diversity of insects, but in comparison to the tropics, little is known about insect spatial distribution, particularly in terms of vertical stratification. We used an aerial lift platform to sample a temperate floodplain forest canopy during two seasons. We aimed to describe patterns of aphid density and diversity in terms of vertical canopy stratification within a 0.2 ha forest plot. Vertical gradient affected both the density and diversity of aphids. There was no general pattern in aphid distribution that applied to the eight tree species included in our survey. The aphid taxocoenosis was stratified differently on particular tree species and changed during the season. Species composition was better explained by aboveground absolute position (in m), while aphid density was better explained by relative height in the tree (position in the crown). Considering that these factors were significant but that the same statistical models excluding any influence of relative or absolute position provided more robust explanations, we concluded that aphid spatial distribution in temperate forests is difficult to simplify. This likely depends on environmental factors, such as wind direction and strength, that affect aphid flight and landing.

Effects of Prey Distribution and Heterospecific Interactions on the Functional Response of Harmonia axyridis and Aphidius gifuensis to Myzus persicae.

Natural enemy guilds normally forage for prey that is patchily distributed simultaneously. Previous studies have investigated the influence of conspecific interactions and prey distribution on the functional response of natural enemies. However, little is known about how prey distribution and heterospecific interactions between natural enemies could affect their foraging efficiency. We examined the effects of prey distribution (aggregate and uniform) and heterospecific interactions on the functional response of a predator, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) and a parasitoid, Aphidius gifuensis Ashmead (Hymenoptera: Braconidae) to the green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae). Type II functional responses were observed in all experiments. Functional response curves of single H. axyridis or A. gifuensis were higher in the aggregate treatment than in the uniform treatment when aphid densities were between 40–180 or 70–170, respectively. When comparing between aggregate and uniform treatments with the heterospecific enemy occurrence, no differences were found in the parasitism efficiency of A. gifuensis, while H. axyridis consumed more aphids in the aggregate treatment than in the uniform treatment when aphid densities were between 50–230. The functional response of individual H. axyridis was not affected by A. gifuensis under two aphid distributions. However, the functional response of a single A. gifuensis and the treatment when A. gifuensis concurrently with H. axyridis overlapped in uniform treatment of above approximately 150 aphids. Our results indicate that the predation rate of H. axyridis was affected by aphid distribution, but was not affected by heterospecific interactions. The parasitism rate of A. gifuensis was affected by aphid distribution, and by heterospecific interactions in both the aggregate and uniform treatments. Thus, to optimize the management efficiency of M. persicae, the combined use of H. axyridis and A. gifuensis should be considered when M. persicae is nearly uniformly distributed under relatively high density.

BIN overlap confirms transcontinental distribution of pest aphids (Hemiptera: Aphididae).

DNA barcoding is highly effective for identifying specimens once a reference sequence library is available for the species assemblage targeted for analysis. Despite the great need for an improved capacity to identify the insect pests of crops, the use of DNA barcoding is constrained by the lack of a well-parameterized reference library. The current study begins to address this limitation by developing a DNA barcode reference library for the pest aphids of Pakistan. It also examines the affinities of these species with conspecific populations from other geographic regions based on both conventional taxonomy and Barcode Index Numbers (BINs). A total of 809 aphids were collected from a range of plant species at sites across Pakistan. Morphological study and DNA barcoding allowed 774 specimens to be identified to one of 42 species while the others were placed to a genus or subfamily. Sequences obtained from these specimens were assigned to 52 BINs whose monophyly were supported by neighbor-joining (NJ) clustering and Bayesian inference. The 42 species were assigned to 41 BINs with 38 showing BIN concordance. These species were represented on BOLD by 7,870 records from 69 countries. Combining these records with those from Pakistan produced 60 BINs with 12 species showing a BIN split and three a BIN merger. Geo-distance correlations showed that intraspecific divergence values for 49% of the species were not affected by the distance between populations. Forty four of the 52 BINs from Pakistan had counterparts in 73 countries across six continents, documenting the broad distributions of pest aphids.

Spatio-temporal variations in wheat aphid populations and their natural enemies in four agro-ecological zones of Pakistan.

Aphids are major pests of wheat crop in Pakistan inflicting considerable economic losses. A better knowledge of landscape scale spatial distribution of aphids and their natural enemies could be used to improve integrated pest management programs. Therefore, the present study aimed to document spatio-temporal variations in populations of wheat aphids and their natural enemies in Pakistan. The 2-year survey study was carried out at ten experimental farms located in five districts of four contrasted agro-ecological zones of eastern Pakistan (Punjab area) i.e. District Chakwal in arid zone, Gujranwala in rice-cropped zone, Faisalabad in central mixed-cropped zone, and Khanewal and Multan in cotton-cropped zone. The dominant aphid species i.e. Schizaphis graminum, Rhopalosiphum padi, R. maidis and Sitobion avenae varied significantly among the five districts surveyed. The population of S. graminum was observed more abundant in arid, R. padi in rice, S. avenae in aird and rice, and R. maidis in cotton-I zones. Aphids ended their population dynamics on 25th March in central mixed-cropped zone and 12th April in other three zones. Various species of natural enemies, mainly Coccinella septumpunctata, C. undecimpunctata, Menochilus sexmaculata, Chrysoperla carnea, Syrphidae and parasitoid mummies were inconsistently observed in four agro-ecological zones. The population of C. septumpunctata, was observed more abundant in rice zone, C. undecimpunctata and C. carnea in cotton-I and arid zones, M. sexmaculata in cotton-I and II zones, Syrphidae in cotton-I zone and parasitoid mummies in rice and arid zones. There were no clear relationships between aphid and the natural enemy populations. The present study may serve as a baseline regarding distribution of wheat aphids and their natural enemies and the results provided insights for further studies on the potential top-down (natural enemies) versus bottom-up (fertilization and irrigation regimes) forces in management of wheat aphids in eastern Pakistan.

A coarse-to-fine network for aphid recognition and detection in the field

In agriculture, aphids are one of the most destructive pests, responsible for major reductions in wheat, corn and rape production leading to significant economic losses. However, manual pest recognition approaches are often time-consuming and laborious for Integrated Pest Management (IPM). In addition, the existing pest detection methods based on Convolutional Neural Network (CNN) are not satisfactory for small aphid recognition and detection in the field because aphids are tiny and often in dense distributions. In this work, a two-stage aphid detector named Coarse-to-Fine Network (CFN) is proposed to address these problems. The key idea of our method is to develop a Coarse Convolutional Neural Network (CCNN) for aphid clique searching as well as a Fine Convolutional Neural Network (FCNN) for refining the regions of aphids in the clique. Specifically, The CCNN detects approximately all the object regions from natural aphid images with various aphid distributions including dense aphid cliques and sparse aphid objects, in which an Improved Non-Maximum Suppression (INMS) strategy is proposed to eliminate overlapping regions. Then, the FCNN further refines the detected aphid regions from the CCNN. The final recognition and detection result would be obtained by combining the outputs from CCNN and FCNN together. Experiments on our dataset show that our CFN achieves an aphid detection performance of 76.8% Average Precision (AP), which improves 20.9%, 18%,13.7% and 12.5% compared to four state-of-the-art approaches.

Does Harvesting Affect the Spatio-Temporal Signature of Pests and Natural Enemies in Alfalfa Fields?

Determining the spatio-temporal distribution and association of pests and natural enemies would be useful for implementing biological control of pests and could also be used in site-specific pest management. In this study, the spatio-temporal distribution and association of aphids, plant bugs, and natural enemies were assessed in alfalfa fields using geo-statistics and spatial analysis by distance indices (SADIE). Additionally, the effect of alfalfa hay-harvesting on the spatial and temporal distribution of these insects was investigated for the first time. Geostatistical analysis indicated that the degree of dependence (DD) was ≥75% for 11 out of 39, 9 out of 35, 3 out of 12, 10 out of 29, and 2 out of 20 datasets for pea aphid Acyrthosiphon pisum, spotted alfalfa aphid Therioaphis maculata, cowpea aphid Aphis craccivora, alfalfa plant bug Adelphocoris lineolatus, and tarnished plant bug Lygus rugulipennis, respectively. The results also indicated that DD was ≥75% in 7 out of 45, 18 out of 45, and 3 out of 20 datasets for Coccinella septempunctata, Hippodamia variegata, and Pterostichus melanarius, respectively. Harvesting decreased the aggregation of the ladybirds, which resulted in a decrease in the index of aggregation. The geo-statistics results were confirmed by SADIE in 75% of datasets. These results can be used in biological control and site-specific management of aphids and plant bugs in alfalfa fields.

Distribution records of aphids (Hemiptera: Phylloxeroidea, Aphidoidea) associated with main forest-forming trees in Northern Europe

We report records of 25 species of aphids collected from four species of woody plants (Pinus sylvestris, Picea abies, Betula pubescens and B. pendula) at 50 study sites in Northern Europe, located from 59° to 70° N and from 10° to 60° E. Critical evaluation of earlier publications demonstrated that in spite of the obvious limitations of our survey, the obtained information substantially contributed to the knowledge of the distribution of aphids in North European Russia, including Murmansk oblast (103 species recorded to date), Republic of Karelia (58 species), Arkhangelsk oblast (37 species), Vologda oblast (17 species) and Republic of Komi (29 species). We confirm the occurrence of Cinara nigritergi in Southern Karelia; Pineus cembrae, Cinara pilosa and Monaphis antennata are for the first time recorded in Norway.