Aphid Density Research Articles

Influence of the Surrounding Plants by Rapeseed Field on Population Density of Cabbage Aphid (Brevicoryne brassicae L.) and its Biological Enemies

The result revealed that the peak of population density of cabbage aphid Brevicoryne brassicae was 523.20 individuals/plant on 21 March in edges of rapeseed field and was 1141.67 individuals/plant in center of the field. Results revealed that population density of cabbage aphid in rapeseed fields surrounded by cover crops significantly were low compared with that of monoculture rapeseed. The location of rapeseed plants (in edges or in center) significantly affected (p

Infestation Rates, Seasonal Abundance of Aphids and Relationships with Some Environmental Factors in Different Forest Habitats in Southwestern Türkiye

Aim of study: It was to determine the infestation rate and seasonal abundance of aphids and their relationships with some environmental factors in forests. Area of study: The study was conducted in Pinus nigra, P. brutia, Cedrus libani, Abies cilicica, Juniperus spp., Quercus spp. and Robinia pseudoacacia forests (34 sampling areas) in Isparta. Materials and methods: Systematic sampling was carried out monthly throughout April-October in 2019-2020. As aphid density and infestation rates were determined, 30 cm shoots were taken from 10 trees. The slope, aspect, elevation, forest characteristics, daily minimum, average, and maximum temperature and total precipitation were recorded. Main results: Abundance were highest in P. nigra, Quercus and Robinia pseudoacacia forests in both years. There was a significant correlation between abundance and development stages (p

Remote sensing reveals the importance of seminatural habitat and irrigation on aphid biocontrol in arid agroecosystems

Abstract Remote sensing and spatial analyses are increasingly used to understand the role of seminatural habitats in biocontrol, but knowing how to best leverage these tools is a persistent challenge. In arid agroecosystems, irrigation often exaggerates the differences between crop fields and their interspaces. Weeds adjacent to irrigated fields are thus often some of the only persistent vegetation. Remote sensing may be essential to capture the effect of this fine‐scale variation on pest biocontrol. We examined the role of land‐cover in determining the degree of aphid pest pressure and biocontrol in irrigated alfalfa fields in the Great Basin Desert (Nevada, USA). We experimentally manipulated predator densities to determine true agents of aphid biocontrol in this system. We then assessed land‐cover and spatial scale using alternative methods to determine the approaches that best defined the combined direct and indirect effects of seminatural habitat on aphid pest suppression. A remote‐sensing approach revealed the importance of land‐cover to aphid biocontrol more clearly than conventional vegetation surveys. In particular, remote sensing revealed that weedy patches within alfalfa fields reduced aphid densities, whereas flood irrigation increased aphid densities. Our experiments confirmed that coccinellid beetles are important aphid biocontrol agents. Coccinellids were positively associated with weedy land‐cover that was spatially close to alfalfa fields, particularly in the spring. Other predator taxa were also associated with distinct landscape features, though these associations varied between spring and fall. Solution: Weedy seminatural habitat near alfalfa fields, occurring along field margins and the banks of irrigation ditches, was positively associated with the density of coccinellid beetles and associated aphid pest suppression. Remote sensing excelled at identifying these areas and their effects, highlighting its utility as a management tool. Preserving these weedy areas can enhance aphid biocontrol, but farmers must consider potential trade‐offs between the control of insect‐pests and weeds.

Population density of aphids infesting some citrus trees species and its predators and parasitoids in recently reclaimed areas in Skarkia province, Egypt

Population density of aphids infesting some citrus trees species and its predators and parasitoids in recently reclaimed areas in Skarkia province, Egypt

Predatory potential of Coccinella undecimpunctata L. (Coleoptera, Coccinellidae) on Aphis craccivora Koch. (Hemiptera, Aphididae) in Ladakh, India

Predatory potential of all instar larvae and adults of Coccinella undecimpunctata (Coleoptera, Coccinellidae), using Aphis craccivora Koch (Hemiptera, Aphididae) was assessed in laboratory settings. The study, conducted with varying aphid densities in rearing jars, showed a significant increase in prey consumption as aphid density rose. Furthermore, prey consumption heightened with larval development, with 4th instars devouring more aphids compared to earlier instars. Female adults exhibited greater aphid consumption than males. Deploying both 4th instar larvae and adults could enhance pest suppression.

Predation Efficiency and Biological Control Potential of Micromus angulatus Against Aphis craccivora

Micromus angulatus (Neuroptera: Hemerobiidae) is a widely distributed and highly effective predator that shows promise as a biological control agent against agricultural pests, particularly Aphis craccivora, the cowpea aphid, which threatens leguminous crops globally. This study aimed to evaluate the predation behaviour, search efficiency, and intraspecific interference of M. angulatus at different developmental stages, including first- to third-instar larvae and adults, in controlling adult A. craccivora populations. The results demonstrated that all developmental stages of M. angulatus exhibited predatory behaviour towards adult aphids, with the functional response fitting the Holling Type II model. The instantaneous attack rates for first-, second-, and third-instar larvae and adults were 1.0017, 1.0448, 0.9581, and 0.9508, respectively; the handling times were 0.0158, 0.0051, 0.0016, and 0.0011 days, respectively; and the theoretical maximum daily predation rates were 63.2911, 196.0784, 625, and 909.0909 aphids, respectively. The pest control efficacies were 63.3989, 204.8672, 598.8311, and 864.3192, respectively. The search efficiency at each developmental stage was negatively correlated with aphid density, which decreased as the prey density increased, with second-instar larvae showing the greatest decrease and adults the least. When the aphid density was fixed, the daily predation rate of individual M. angulatus decreased with increasing conspecific density, indicating that predation was affected by its own density, with the interference effect equation being E = 0.6194P−0.87. These findings indicate that M. angulatus, especially in the third-instar larval and adult stages, has considerable potential as a biological control agent for managing A. craccivora populations in agricultural settings. This study contributes valuable insights for developing sustainable agricultural practices by decreasing reliance on chemical pesticides.

Functional and Numerical Responses of Harmonia axyridis (Coleoptera: Coccinellidae) to Rhopalosiphum nymphaeae (Hemiptera: Aphididae) and Their Potential for Biological Control.

The water lily aphid (Rhopalosiphum nymphaeae) is a highly polyphagous herbivore that causes severe damage to many terrestrial and aquatic plants, especially lotus. Due to environmental concerns about water pollution and other issues caused by chemical control methods, there is an urgent need to develop effective and sustainable control methods. The harlequin ladybird (Harmonia axyridis) is a well-known aphid predator and may pose a potential threat to R. nymphaeae. To study the predation ability of H. axyridis at different developmental stages on R. nymphaeae, we assessed the functional response, attack rate, and search effect of H. axyridis larvae and adults preying on R. nymphaeae. The numerical response of this process was also evaluated under a constant ladybird-to-aphid ratio and constant aphid density conditions, respectively. Our results showed that all predator stages exhibited type II functional responses. The predation rate of individual H. axyridis on R. nymphaeae nymphs significantly increased as prey density increased. In contrast, the search effect of H. axyridis gradually decreased with an increase in prey density. Meanwhile, H. axyridis at different developmental stages possess varying predation abilities; fourth instar and adult H. axyridis were found to be highly efficient predators of R. nymphaeae. H. axyridis adults exhibited the highest predation ability and predation rate, while both the adult and fourth-instar larvae exhibited the highest attack rate. Moreover, fourth-instar larvae exhibited the highest search effect value at initially lower prey densities, although adults surpassed them at higher prey densities. Our results also indicated that H. axyridis exhibited varying degrees of intraspecific interference and self-interference influence as predator density increases. These results strongly support H. axyridis as an effective biocontrol agent for R. nymphaeae.

Local factors have a greater influence on the abundance of alfalfa weevil and its larval parasitoids than landscape complexity in heterogeneous landscapes

ContextThe alfalfa weevil Hypera postica Gyllenhal (Coleoptera: Curculionidae) is one of the most destructive pests of alfalfa worldwide. Both local and landscape-scale factors can significantly influence crop pests, natural enemies, and the effectiveness of biological control services, but the relative influence of these factors is unclear.ObjectivesWe investigated the influence of the local variables and surrounding landscape composition and configuration on the abundance of alfalfa weevil, and on the abundance and parasitism rates of its larval parasitoids, Bathyplectes spp.MethodsWe sampled 65 commercial alfalfa fields along the Ebro Basin, Spain, over a period of 3 years, recording the field characteristics and landscape structure at three buffer radii of 250, 500 and 1000 m from the center of each field.ResultsThe abundance of weevil larvae was positively associated with the field perimeter and with the uncut alfalfa surrounding the pipes of the sprinkler irrigation system, but only one configuration variable was positively correlated: the alfalfa edge density. No local characteristics or landscape structures were associated with the abundance of adult weevils. The abundance of Bathyplectes spp. adults was positively associated to local factors such as the densities of alfalfa weevils and aphids. Few landscape structure variables, such as alfalfa edge density and Simpson’s Diversity Index, had explanatory value only at 250 m buffer radius. The rate of larval parasitism was affected by local variables, such as alfalfa weevil abundance and field age.ConclusionOur results provide, for the first time in the Mediterranean region and Europe, evidence of the relative importance of landscape structure and local factors on the abundance of the alfalfa weevil and its larval parasitoids, Bathyplectes spp. The strongest influences were based on local characteristics.

New okra genotypes for the management of aphids (Hemiptera: Aphididae) in the diverse ecological landscapes of Central Africa.

Various aphid species, including Aphis gossypii Glover (Hemiptera: Aphididae), are considered important pests of okra and other vegetables. Previous studies under 1 environment in Cameroon, Central Africa, had found multiple okra genotypes with resistance to A. gossypii. However, the stability and yield performance of the "resistant" genotypes across different environments were unknown. Ten previously identified aphid-resistant okra genotypes along with 1 commercial variety and a local landrace (specific to a given location) were compared during 2 seasons in replicated trials in 4 agro-ecological zones of Cameroon that also represent large areas of Central Africa. Aphid populations and okra yield parameters were evaluated. Breeding values were predicted using a linear mixed model for all data, and genotypes by location interactions were identified. The area under the infestation pressure curve (AUIPC) was calculated using aphid count data and subjected to resistance analysis. The Local-the most susceptible with the highest breeding value (+2.33)-and VI060794-one of the moderately resistant-genotypes had the highest yield per hectare. The only resistant genotype VI036213 had the lowest breeding value (-2.20). Genotype × location interactions were significant for yield, pod width, and plant height, while location variance was significant for all parameters evaluated. When considering that higher aphid densities could lead to greater pesticide use and, therefore higher production and environmental costs, the high-yielding VI060794-with moderate aphid resistance across multiple environments-presents an alternative or substitute for local landraces across multiple agro-ecologies of Cameroon and (by extension) Central Africa.

Intraguild species presence alters Aphidoletes aphidimyza (Diptera: Cecidomyiidae) and Aphidius gifuensis (Hymenoptera: Braconidae) foraging responses.

The predatory gall midge, Aphidoletes aphidimyza (Rondani), and tobacco aphid cocoon wasp, Aphidius gifuensis Ashmead, are important natural enemies of Myzus persicae (Sulzer) (Hemiptera: Aphididae). Predation by A. aphidimyza and A. gifuensis can regulate M. persicae; however, how interspecific interference competition affects their foraging efficiency is unknown. Here, we investigated the consumption and parasitization abilities of A. aphidimyza 3rd instar larva and A. gifuensis adults under various conditions. Consumption of parasitized aphids by A. aphidimyza 3rd instar larvae was significantly lower than that of nonparasitized controls, with a substantial increase in handling time. The presence of A. gifuensis adults did not significantly affect the predation capacity of A. aphidimyza larvae. Relative to controls, A. aphidimyza larvae predation trace (PT) and imago activity significantly decreased A. gifuensis parasitism rates at different aphid densities. Further, A. aphidimyza larvae PT increased the A. gifuensis handling time of M. persicae, whereas the presence of A. aphidimyza adults had the opposite effect. Coexistence with heterospecific natural enemies reduced the parasitic capacity of A. gifuensis, whereas A. aphidimyza larvae predation capability was influenced to a lesser extent. Our results demonstrate that intraguild interactions strongly influence the predatory and parasitic efficacy of A. aphidimyza and A. gifuensis, although the effect on A. gifuensis was more pronounced. For effective biological control of M. persicae using A. aphidimyza and A. gifuensis, we recommend releasing A. aphidimyza first to mitigate intraguild predation and enhance the overall success of the pest control program.

Foliar Application of Silicon Influences Crop Productivity, Dry Matter Accumulation, Water Use Efficiency, Lodging Score, and Aphid Density in Wheat (Triticum aestivum L.)

ABSTRACT Silicon (Si) is a versatile nutrient that plays an instrumental role in mitigating biotic and abiotic stresses besides improving growth and yield of graminaceous crops. We hypothesized that application Si would significantly improve productivity and resilience of wheat. Hence, the objectives were a) to assess the impact of Si application on wheat growth, productivity, nutrient uptake, water use efficiency, and b) to determine the potentiality of Si in mitigating lodging and aphid density. Therefore, we conducted a field experiment with five levels of Si (0, 2, 4, 6, and 8 g Si liter−1) at three growth stages (crown root initiation, tillering, and jointing stage) using a factorial randomized block design replicated three times. The results showed that increasing Si doses positively influenced plant height, dry matter accumulation (DMA), leaf area index (LAI), yield, and nutrient uptake. The highest grain and straw yield were observed with 8 g Si liter−1, followed by 6 g Si liter−1, while the control had the lowest yields. With 8 g Si liter−1, grain yield, straw yield, and Si uptake increased by 10.5%, 13.5%, and 26.3%, respectively, compared to the control. Additionally, Si application at 8 g Si liter−1 significantly reduced the density of S. avenae (aphids) by 81.4% and lodging by 75.1% compared to the control. Overall, the study demonstrated that increasing Si doses enhanced various growth and yield parameters, with 8 g Si liter−1 and 6 g Si liter−1 showing superior results. Among the growth stages, foliar application of Si during the tillering stage exhibited better performance in terms of growth, yield, and nutrient uptake in wheat. Therefore, the study concludes that Si fertilization at a rate of 8 g Si liter−1 during the tillering stage can effectively improve growth, productivity, and nutrient uptake in wheat in the southern region of Rajasthan.

Detecting sorghum aphid infestation in grain sorghum using leaf spectral response

Sorghum aphid, Melanaphis sorghi (Theobald) have become a major economic pest in sorghum causing 70% yield loss without timely insecticide applications. The overarching goal is to develop a monitoring system for sorghum aphids using remote sensing technologies to detect changes in plant-aphid density interactions, thereby reducing scouting time. We studied the effect of aphid density on sorghum spectral responses near the feeding site and on distal leaves from infestation and quantified potential systemic effects to determine if aphid feeding can be detected. A leaf spectrometer at 400–1000 nm range was used to measure reflectance changes by varying levels of sorghum aphid density on lower leaves and those distant to the caged infestation. Our study results demonstrate that sorghum aphid infestation can be determined by changes in reflected light, especially between the green–red range (550–650 nm), and sorghum plants respond systemically. This study serves as an essential first step in developing more effective pest monitoring systems for sorghum aphids, as leaf reflection sensors can be used to identify aphid feeding regardless of infestation location on the plant. Future research should address whether such reflectance signatures can be detected autonomously using small unmanned aircraft systems or sUAS equipped with comparable sensor technologies.

Compatibility of the Entomopathogenic Fungus Metarhizium anisopliae (Ascomycota: Hypocreales) and the Predatory Coccinellid Menochilus sexmaculatus (Col.: Coccinellidae) for Controlling Aphis gossypii (Hem.: Aphididae).

Metarhizium anisopliae (Ascomycota: Hypocreales) is an entomopathogenic fungus considered a key factor in developing integrated management of several insect pests on a variety of crops. The predatory coccinellid, Menochilus sexmaculatus (Col.: Coccinellidae), is also an important natural enemy that must be conserved for effective aphid control. Laboratory studies were conducted under controlled conditions to investigate the interaction between M. anisopliae isolate IRN. 1 and the coccinellid predator M. sexmaculatus in combating Aphis gossypii Glover (Hem.: Aphididae). The combined application of M. sexmaculatus and M. anisopliae led to significant reduction in aphid populations. The foraging behavior of M. sexmaculatus notably facilitated the dispersion of M. anisopliae conidia to uninfected plants, resulting 54 ± 1.3% decrease in aphid density after 10days. In both choice and non-choice experiments, female adult M. sexmaculatus to fungus-infected aphids was offered as prey and avoided as a food source during all starvation periods. However, live and dead non-fungus-infected aphids were fed upon. The result revealed the compatibility between M. sexmaculatus and M. anisopliae, which may provide a sustainable strategy for the effective management of A. gossypii in a cropping system.

Estimating Yield Gap of Wheat (Triticum aestivum L.) using the Comparative Performance Analysis (CPA) Method in the Bam, Narmashir and Fahraj Counties of Kerman Province

Background: Yield gap is distance between potential yield and attainable yield (yield gap= potential yield-attainable yield) in order to increase the crop yield and the goal of sustainable agriculture. Methods: This study was conducted in Bam, Narmashir and Fahraj counties in 219 separate farms (79 farms in Bam, 72 farms in Narmashir and 68 farms in Fahraj) during the years 2019 and 2020 to investigate the yield gap of wheat and determine the limiting factors and their contributions to yield reduction, using the comparative performance analysis (CPA) method. All information related to soil factors, management factors, climatic factors and agronomic traits (53 variables) were measured and recorded. The relationship between wheat yield and all variables was examined using a stepwise multiple regression method. A production model was determined for soil and management factors. Result: The results showed a yield gap between actual yield and potential yield in the regions of Bam, Narmashir and Fahraj, which were 1770.8, 1817.61 and 1605 kg per hectare, respectively. Since the actual yield in these regions was 4248, 4228 and 3161 kg per hectare, the yield gap was observed to be 33.6%, 30% and 29.4%, respectively. The effective factors in reducing the yield in the Bam region included water shortage (19.48%), nitrogen deficiency (16.09%), delayed planting (15.40%), soil available phosphorus deficiency (10.14%), weed density (10.8%), soil organic carbon (13.59%) and inappropriate plant density (14.47%). In the Narmashir region, water shortage (26.68%), nitrogen deficiency (18.86%), soil organic carbon (11.78%), inappropriate plant density (12.43%), wheat aphid (19.58%) and weed density (10.64%) caused yield reduction. In the Fahraj region, water shortage (20.65%), nitrogen deficiency (19.62%), delayed planting (9.44%), soil available phosphorus deficiency (8.45%), weed density (12%), soil salinity (12.80%) and black stem disease (17%) caused a decrease in wheat yield.

Developing a hybrid convolutional neural network for automatic aphid counting in sugar beet fields

Aphids can cause direct damage and indirect virus transmission to crops. Timely monitoring and control of their populations are thus critical. However, the manual counting of aphids, which is the most common practice, is labor-intensive and time-consuming. Additionally, two of the biggest challenges in aphid counting are that aphids are small objects and their density distributions are varied in different areas of the field. To address these challenges, we proposed a hybrid automatic aphid counting network architecture which integrates the detection network and the density map estimation network. When the distribution density of aphids is low, it utilizes an improved Yolov5 to count aphids. Conversely, when the distribution density of aphids is high, it switches to CSRNet to count aphids. To the best of our knowledge, this is the first framework integrating the detection network and the density map estimation network for counting tasks. Through comparison experiments of counting aphids, it verified that our proposed approach outperforms all other methods in counting aphids. It achieved the lowest MAE and RMSE values for both the standard and high-density aphid datasets: 2.93 and 4.01 (standard), and 34.19 and 38.66 (high-density), respectively. Moreover, the AP of the improved Yolov5 is 5 % higher than that of the original Yolov5. Especially for extremely small aphids and densely distributed aphids, the detection performance of the improved Yolov5 is significantly better than the original Yolov5. This work provides an effective early warning caused by aphids in sugar beet fields, offering protection for sugar beet growth and ensuring sugar beet yield. The datasets and project code are released at: https://github.com/JunfengGaolab/Counting-Aphids.

Dynamic intraguild interactions between two sympatric and congeneric coccinellid species associated with aphids could explain their coexistence in citrus agroecosystems

Scymnus interruptus and Scymnus subvillosus (Coleoptera: Coccinellidae) are the most frequent aphid predators in Western Mediterranean citrus agroecosystems. Intraguild predation (IGP) between them would be expected, but how IGP might affect their coexistence and biological control function remains unknown. In this work, we assess the frequency of predator encounters in the field and investigate intraguild predation between these two predators in laboratory settings. Different field prey scenarios derived from the field observations were simulated with the two dominant aphid species in this agroecosystem, Aphis gossypii and Aphis spiraecola.Scymnus subvillosus and S. interruptus engaged in IGP but the magnitude and symmetry varied with the prey species and abundance. At high aphid densities, IGP was symmetric and weak, whereas, at low aphid densities, IGP was strong and very asymmetric, with S. interruptus taking the role of the intraguild predator. The developmental time of S. subvillosus was reduced when competing with S. interruptus at high extraguild prey densities. The adult size of both predators under weak IGP also increased even when the developmental time had been reduced.We predict that high aphid infestations in the spring would benefit S. subvillosus, while the strong and asymmetric IGP at low aphid infestations would hinder its coexistence with S. interruptus. Our results give a theoretical explanation to what is observed in the field: S. subvillosus is typically dominant during the high aphid infestations of the spring, whereas S. interruptus increases in relative dominance during the summer and fall when aphid abundance is much less.

Functional Response of Chrysoperla Zastrowi Sillemi (Esben-Peterson) on Lipaphis erysimi (Keltenbach)

Biological control of insect pests depends upon predating potential of natural enemies, which in turn relate to their functional response that is key to selection of a proper species for the biological control programs. The main aim of the study was to access the functional response of second instar grub of C. zastrowi sillemi (Neuroptera: Chrysopidae) on Raya (Brassica juncea) aphid Lipaphis erysimi (Keltenbach). Five different predator: prey densities of aphids (1:50, 1:100: 1:150, 1:200 and 1:250) were taken and results indicated the type-II functional curve response by logistic regression analysis of C. zastrowi sillemi on L. erysimi. Hollings Type II functional response signifies that the rate of prey consumption by a predator rises as prey density increases, but eventually remains constant in spite of increase in prey density. The aphids consumption, search rate (a`) and maximum predation rate (1/Th) was recorded less (7.36, 0.06 and 0.40) as compared (7.56, 0.068and 0.467) when grubs fed on artificial diet. However, time taken to handle a prey by second instar grub was more (2.55) on natural diet but less (2.17) on artificial diet.

Emulsifiable oil-formulated Beauveria bassiana competes with imidacloprid for seasonal control of cereal aphids in Zhejiang, China.

Alternatives to neonicotinoids against cereal aphids are needed to mitigate aphid resistance and non-target effects. The emulsifiable oil formulations of two Beauveria bassiana strains, namely Bb registered as a mycoinsecticide and TBb overexpressing an endogenous virulence factor, were tested for seasonal control of cereal aphids at the elongating (April 7) to milk ripening (May 12) stages of winter wheat crop in Yuhang, Zhejiang. Each of three field trials consisted of blank control and the treatments (three randomized 100-m2 plots per capita) of each fungal strain sprayed biweekly at rates of 1.0 × 1013 and 1.5 × 1013 conidia ha-1 and 10% imidacloprid WP sprayed biweekly at a label rate. Tiller infestation percentage and aphid density in the 5-week field trials after the first spray were reduced to 18.7-22.4% and 9.1-12.4 aphids per tiller in the fungal treatments, and 12.8-25.3% and 2.8-20.9 aphids per tiller in the chemical treatment, contrasting with 49.2-60.3% and 37.1-108.5 aphids per tiller in the control. Percent control efficacies (±SD) computed with weekly aphid densities over the period averaged 84.0 ± 1.6 and 85.3 ± 1.8 versus 78.0 ± 4.0 and 79.9 ± 3.2 in the high-rate versus low-rate treatments of Bb and TBb, respectively, and 84.5 ± 7.8 in the chemical treatment. Imidacloprid showed faster kill action but more variable efficacy than the fungal treatments throughout the trials. Either Bb or TBb formulation competes with imidacloprid in reducing percent infestation and aphid density. The overall efficacy was significantly higher in the treatments of TBb than of Bb. © 2024 Society of Chemical Industry.

Application of a Mechanistic Model to Explore Management Strategies for Biological Control of an Agricultural Pest

Despite the known benefits of integrated pest management, adoption in Australian broadacre crops has been slow, in part due to the lack of understanding about how pests and natural enemies interact. We use a previously developed process-based model to predict seasonal patterns in the population dynamics of a canola pest, the green peach aphid (Myzus persicae), and an associated common primary parasitic wasp (Diaeretiella rapae), found in this cropping landscape. The model predicted aphid population outbreaks in autumn and spring. Diaeretiella rapae was able to suppress these outbreaks, but only in scenarios with a sufficiently high number of female wasps in the field (a simulated aphid:wasp density ratio of at least 5:1 was required). Model simulations of aphid-specific foliar pesticide applications facilitated biological control. However, a broad-spectrum pesticide negated the control provided by D. rapae, in one case leading to a predicted 15% increase in aphid densities compared to simulations in which no pesticide was applied. Biological and chemical control could therefore be used in combination for the successful management of the aphid while conserving the wasp. This modelling framework provides a versatile tool for further exploring how chemical applications can impact pests and candidate species for biological control.

Markers of resistance to pea aphid, Acyrthosiphon pisum Harris in Pisum sativum L. accessions

One of the major insect pests in Pisum sativum L. (is Acyrthosiphon pisum Harris (Hemiptera: pests in Pisum sativum L. (Hemiptera: Aphididae) is Acyrthosiphon pisum Harris (Hemiptera: Aphididae). An effective strategy for aphid control is the resistant host plant use. The current study aimed to identify resistance mechanisms and assess biochemical and morphological markers of pea aphid resistance in pea accessions. Meteorological variables affected the pea aphid density, which positively correlated with temperature, while precipitation amount and humidity negatively impacted. The aphid number was significantly and positively associated with the leaf area and the nitrogen content but negatively correlated with calcium and phosphorus levels. The pea aphid-resistant cultivars L 123-7-11, L 128-1and L 125-5 had small leaf areas, and high phosphorus and calcium content but a low nitrogen level. In the mutual influence of the plant indicators, phosphorus concentration had the highest negative impact on pea aphid density, followed by calcium. The plant marker inclusion in the pea breeding process is an efficient tool for a substantial selection program improvement for aphid resistance. Therefore, resistant host plants are essential tools promoting considerable selection program improvement for aphid resistance in the P. sativum breeding process and helping develop sustainable and environmentally friendly agriculture.