Search Results (39)

Due to its abundance, bird cherry–oat aphid is the most important vector in Poland of the complex of viruses causing barley yellow dwarf virus (BYDV). These viruses infect all cereals. During the growing season, cereal plants are exposed to many species of agrophages, which can limit their growth, development and yield. As observed for many years, global warming contributes to changes in the development of many organisms. Aphids (Aphidoidea), which are among the most important pests of agricultural crops, respond very dynamically to these changes. Under favorable conditions, their populations can increase several-fold within a few days. The bird cherry–oat aphid (Rhopalosiphum padi L.) is a dioecious species that undergoes a seasonal host shift during its life cycle. Its primary hosts are trees and shrubs (Prunus padus L.), while secondary hosts include cereals and various grass species. R. padi feeds directly on bird cherry tree, reducing its ornamental value, and on cereals, where it contributes to yields losses. The species can also damage plants indirectly by transmitting harmful viruses. Indirect damage is generally more serious than direct feeding injury. Monitoring aphid flights with a Johnson suction trap (JST) is useful for plant protection, which enables early detection of their presence in the air and then on cereal crops. To provide early detection of R. padi migrations and to study the dynamics of abundance, flights were monitored in 2020–2024 with Johnson suction traps at two localities: Winna Góra (Greater Poland Province) and Sośnicowice (Silesia Province). The aim of the research conducted in 2020–2024 was to study the dynamics of the bird cherry–oat aphid (Rhopalosiphum padi L.) population in relation to meteorological conditions as recorded by a Johnson suction trap. Over five years of research, a total of 129,638 R. padi individuals were captured using a Johnson suction trap at two locations (60,426 in Winna Góra and 69,212 in Sośnicowice). In Winna Góra, the annual counts were as follows: 5766 in 2020, 6498 in 2021, 36,452 in 2022, 5598 in 2023, and 6112 in 2024. In Sośnicowice, the numbers were as follows: 6954 in 2020, 9159 in 2021, 49,120 in 2022, 3855 in 2023, and 124 in 2024. The year 2022 was particularly notable for the exceptionally high abundance of R. padi, especially in the autumn. Monitoring crops for the presence of pests is the basis of integrated plant protection. Climate change, modern cultivation technologies, and increasing restrictions on chemical control are the main factors contributing to the development and spread of aphids. Therefore, measures based on monitoring the level of threat and searching for control solutions are necessary. Full article

The bird cherry–oat aphid (Rhopalosiphum padi L.) constitutes approximately 70–80% of all aphid individuals found on cereal crops in Poland. It is considered one of the most economically important cereal pests, causing indirect damage through virus transmission and leading to substantial yield losses in agricultural crops. Previous studies have shown that the anholocyclic development of this species is strongly correlated with temperature patterns. Between 2018 and 2022, an analysis of the population structure of R. padi (gynoparae, males, and anholocyclic forms) was conducted during the autumn periods using a Johnson suction trap in Western Poland (Greater Poland region), in an area cultivated mainly with cereals. In years with a higher number of days characterized by mean daily air temperatures known to induce changes in R. padi biology, a marked decrease in the proportion of males within autumn populations was observed, along with a delayed onset of their occurrence. In each year of the study, temperature conditions conducive to the development of anholocyclic forms of R. padi were recorded. The abundance of individual morphs and forms of R. padi in autumn collections using the Johnson suction trap was distinctly variable and characterized primarily by a relatively low proportion of males in the catches (except for the years 2020–2021) within the total number of aphids of this species collected. An opposite trend was observed in these years regarding the proportion of anholocyclic forms of R. padi (2.61% of the entire population in 2020 and 3.51% in 2021). Full article

Oat (Avena sativa L.) is a vital cereal and feed crop grown worldwide, but its production is increasingly threatened by barley yellow dwarf virus (BYDV) and aphid infestations in arid and semi-arid regions, particularly in northern China. This study explores the transcriptomic and physiological responses of two oat cultivars MN10253 (resistant) and Qingyin 1 (susceptible) to BYDV at 0, 2, 8, 24, and 48 h post-infection. A combination of phytohormone profiling, differential gene expression analysis, and pathway enrichment was employed to identify mechanisms underpinning disease resistance. Comparative time-course transcriptome analysis revealed 9285 and 8904 differentially expressed genes (DEGs) in MN10253 and Qingyin 1, respectively. Key pathways such as MAPK signaling, plant–pathogen interaction, and hormone signal transduction were significantly enriched. The resistant cultivar exhibited robust activation of pattern-triggered immunity and effector-triggered immunity pathways, marked by upregulation of genes like RPS2, HSP90, and WRKY33, alongside higher expression of salicylic acid (SA)-responsive genes, such as NPR1 and PAL. Conversely, the susceptible cultivar displayed weaker or delayed activation of these defense pathways. Hormonal analysis further demonstrated higher SA accumulation in MN10253 during early infection, correlating with enhanced defense responses. In contrast, Qingyin 1 showed elevated levels of auxin and abscisic acid, which are linked to suppressed immunity. This study underscores the central role of immunity responses and phytohormone pathways in mediating oat resistance to BYDV, highlighting the tradeoff between growth and defense modulated by hormonal crosstalk. These findings advance our understanding of host–pathogen dynamics in oats and provide valuable insights for breeding disease-resistant cultivars. Full article

Background/Objectives: The bird cherry-oat aphid, Rhopalosiphum padi, is a major global pest of cereal crops and exhibits wing polyphenism, producing both winged (dispersive) and wingless (reproductive) morphs. Methods: To identify potential RNAi targets that could specifically disrupt the migratory winged morph, we conducted a comparative transcriptomic analysis of adult aphids. Differentially expressed genes (DEGs) were identified, annotated for their functions, and analyzed for their involvement in metabolic pathways. Results: Significant differences were observed in 121 genes between morphs: 13 were upregulated in the winged morph, while 108 were downregulated. Most DEGs were enriched in lipid metabolism and circadian rhythm pathways, suggesting that wing polymorphism may be adaptively linked to energy resource allocation strategies. Conclusions: This study firstly reveals the adult-stage-specific regulatory roles of lipid metabolism and circadian rhythm pathways in wing polyphenism, identifying six candidate genes (BCORL1, AMP-L, Pfl, Lip3L, HLFL(X7), and HLFL(X4)) for RNAi-based biocontrol strategies targeting migratory morphs. Full article

The bird cherry-oat aphid Rhopalosiphum padi (L.) poses a significant threat to wheat production, resulting in substantial yield reductions. Abamectin and acetamiprid are frequently utilized for management. This study assessed the sublethal effects of abamectin and acetamiprid on R. padi through life table analysis and enzyme activity assays. At 24 h, the LC₁₀ and LC₃₀ values for abamectin to R. padi were 0.063 mg/L and 0.252 mg/L, respectively, while, for acetamiprid, the corresponding values were 0.065 and 0.293 mg/L. The results indicated that exposure to sublethal concentrations of abamectin (AB-LC₁₀) extended the longevity of R. padi F₀ generation, while acetamiprid (AC-LC₁₀ and AC-LC₃₀) decreased it. Furthermore, the fecundity of the F₀ generation was significantly reduced following exposure to AB-LC₃₀, AC-LC₁₀ and AC-LC₃₀. In the F₁ generation, exposure to sublethal concentrations of acetamiprid negatively impacted on R. padi, as evidenced by a significant reduction in longevity; fecundity and population parameters (R₀, r, λ, s_xj, l_x, l_xm_x, v_xj and e_xj). Conversely, sublethal concentrations of abamectin did not significantly affect these parameters. Additionally, population projections revealed a significantly smaller total population size of R. padi in the acetamiprid-exposed group compared to both the abamectin-exposed and control groups. Except these population-level effects, the activities of detoxification enzymes, including cytochrome P450 monooxygenases (P450), glutathione S-transferases (GST) and carboxylesterases (CarE), changed differently after treatments. These results suggest that sublethal concentrations of acetamiprid, but not abamectin, significantly inhibit the population growth of R. padi. These insights are crucial for R. padi control and facilitate the development of effective control strategies that take into account these sublethal effects in integrated pest management strategies targeting R. padi. Full article

Bird cherry-oat aphid (Rhopalosiphum padi L.; Hemiptera: Aphididae) and English grain aphid (Sitobion avenae Fabricius; Hemiptera: Aphididae) are economically important cereal crop pests and effective vectors of barley yellow dwarf virus (BYDV). While these aphid species have traditionally been managed with synthetic chemical insecticides, their use is increasingly difficult due to target organism resistance and potential non-target effects. Exploiting genetic diversity among cereal varieties offers a more sustainable control strategy. In this study, we evaluated how an experimental confinement method using clip cages to restrict an aphid to a single leaf versus free movement on the host plant affects the performance (growth and reproduction) of these two aphid species on various wheat varieties. Aphid performance was significantly influenced by both confinement and wheat variety. Notably, the two aphid species responded in opposite ways to confinement, with S. avenae growing quicker and producing a greater number of offspring under clip cage confinement compared to R. padi, which performed better when left free on the plant. This contrast is likely explained by species-specific feeding site preferences and sensitivity to the microenvironment created by the clip cages. We also found significant differences in aphid performance among host plant varieties, with both aphid species achieving their lowest growth rates on “Wolverine”, a modern BYDV-resistant wheat cultivar. Although none of the tested varieties were completely resistant to aphids, our results indicate that existing commercial cultivars may already carry partial resistance traits that can be leveraged in integrated pest management programs to help suppress aphid populations. Full article

In light of the current global challenges, such as climate change, the overexploitation of natural resources, and increasing food demand, drought-tolerant forage crops present substantial potential for development in dryland regions. However, there is a notable gap in research that integrates yield improvement, nutritional quality enhancement, and resistance to pests and diseases in the production of forage crops in semi-arid areas. Therefore, selecting oat forage varieties that exhibit high yield, superior quality, and enhanced pest resistance can substantially advance the forage industry and animal husbandry in semi-arid regions. In this study, ten oat varieties, including both domestic and international cultivars, were cultivated in a semi-arid region (Weiqi town, Gansu Province) during the 2023–2024 growing season. A comprehensive analysis was performed to assess the yield, quality, and pest resistance of these varieties. All ten oat varieties successfully completed their growth cycles. Among them, Everleaf 126 exhibited a shorter plant height compared to the other varieties, measuring 103.32 cm and 115.14 cm over two years. However, its superior leaf area and tiller number led to the highest hay yields (11,819.33 kg/ha and 13,550.67 kg/ha) and seed yields (4913.20 kg/ha and 5242.33 kg/ha). Additionally, Everleaf 126 demonstrated significantly higher leaf–stem ratios (0.35 and 0.41), crude protein content (8.52% and 9.13%), and crude fat content (2.19% and 2.69%) relative to other oat varieties (p < 0.05). Furthermore, it showed the best resistance to powdery mildew (MR), red leaf disease (HR), leaf spot disease (MR), and aphids (R). The plant height of Kona was the lowest, measuring 81.22 cm and 87.16 cm, respectively, with the fewest number of tillers and the smallest leaf area. Baler II exhibited the lowest hay yield at 8770.10 kg/ha and 7898.33 kg/ha, as well as the lowest seed yield at 3409.33 kg/ha and 3323.90 kg/ha. Kona also had the lowest leaf–stem ratio (0.19 and 10.13) and crude protein content (5.74% and 6.58%), while exhibiting the highest neutral detergent fiber (NDF) and acid detergent fiber (ADF) values. Furthermore, Kona showed the poorest resistance to powdery mildew (MS) and leaf spot (MS). Finally, based on the comprehensive evaluation analysis of the membership function, in the semi-arid region, Everleaf 126 achieved the highest overall performance based upon a comprehensive evaluation, followed by Molasses and Longyan No.3. In comparison, Kona received the poorest performance. Full article

The planting of oat varieties is influenced by factors such as their inherent traits, ecological regional climate, altitude conditions, and resistance differences, resulting in a decrease in both forage yield and quality. It is crucial to carefully select appropriate oat varieties for different ecological regions in order to enhance forage yield and quality, thereby facilitating the advancement of the grass industry. The correlation between the indices and the relationship between the indices and varieties were investigated through rigorous correlation analysis and principal component analysis. By employing gray correlation analysis, the 21 indices were transformed into 15 independent comprehensive indices. Subsequently, based on a comprehensive analysis, oat varieties suitable for cultivation in different ecological regions were identified. In this study, fifteen domestic and foreign oat varieties were cultivated in the semi-arid region of Weiqi Town and the alpine region of Damaying Town in Shandan County throughout 2023. Among the yield traits, Everleaf 126 exhibited a significantly lower plant height while possessing the largest leaf area, the highest number of effective tillers, and achieving the highest hay and seed yields (p < 0.05), which were 13,199 kg/ha and 5136 kg/ha, respectively. The plant height of Longyan No.3 in Damaying Town was significantly higher than that of other varieties. This variety also demonstrated the highest number of effective tillers, along with the greatest hay yield (7783 kg/ha) and seed yield (5033 kg/ha). Among the evaluated quality traits, Everleaf 126 in Weiqi Town exhibited the highest leaf–stem ratio, crude protein content, and crude fat content (p < 0.05). In contrast, Mengshi in Damaying Town had the highest leaf–stem ratio, while Longyan No.3 demonstrated the highest levels of crude protein and crude fat content. Furthermore, Molasses displayed the highest soluble sugar content in both locations (p < 0.05). The resistance of 15 oat varieties to pests and diseases was found to be lower in Weiqi Town compared to Damaying Town. Notably, Everleaf 126 exhibited the highest resistance to powdery mildew, red leaf disease, leaf spot disease, and aphids among the varieties tested in Weiqi Town. In contrast, Longyan No.3 demonstrated superior resistance in Damaying Town. In conclusion, based on a comprehensive analysis of the gray correlation degree, in the semi-arid region, Everleaf 126 exhibited the most superior performance, followed by Molasses and Longyan No.3. In the alpine region, Longyan No.3 demonstrated the highest overall performance, followed closely by Molasses and Mengshi. These varieties exhibit significant potential for promotion as high-yield, high-quality forage oats in semi-arid and alpine environments. Full article

(1) Background: Genistein is a naturally occurring flavonoid with a rich spectrum of biological activities, including plant-herbivore interactions. The aim of the study was to evaluate the effect of exogenous application of genistein on aphid behavior during probing in plant tissues. (2) Methods: Vicia faba, Brassica rapa ssp. pekinensis, and Avena sativa were treated transepidermally with a 0.1% ethanolic solution of genistein, and the probing behavior of generalist aphid species Aphis fabae, Myzus persicae, and Rhopalosiphum padi was monitored on their respective treated and untreated host plants using electropenetrography (=electrical penetration graph technique, EPG); (3) Results: Genistein did not deter aphid probing activities in non-phloem tissues. In A. fabae and R. padi, a trend towards reduction and in M. persicae a trend towards increase in phloem sap ingestion occurred on genistein-treated plants, but these trends were not statistically significant. (4) Conclusions: Genistein is not a deterrent chemical against generalist aphid species studied; therefore, it is not recommended for practical application. Full article

Different herbivorous species that share a host plant may interact via competition or facilitation, depending on whether the interaction partners are hindered by or benefit from the interaction. Sap-sucking insects, such as aphids, can influence each other indirectly by altering the composition of the shared phloem sap. Aphid-induced changes in the plant may affect aphid performance and lead to a shift in the balance between different co-occurring aphid species. In this study, we compared the performance of the English grain aphid (Sitobion avenae) and the bird cherry-oat aphid (Rhopalosiphum padi) simultaneously infesting leaves or ears of wheat (Triticum aestivum) plants, which had been either previously infested by S. avenae or kept uninfested. Colonies of S. avenae were larger on ears than on leaves, while the opposite pattern was found for R. padi. Pre-infestation of ears, but not of leaves, by S. avenae led to a higher total aphid number and colony size of S. avenae at some time points. The balance between the two species was only slightly affected by previous infestation at some time points. The findings of this study contribute to the understanding of plant–aphid as well as aphid–aphid interactions in agricultural fields. Full article

Nitric oxide (NO) and other reactive nitrogen species (RNS) are considered to be signaling molecules in higher plants involved in the regulation of growth and development processes. However, the molecular mechanisms of their formation, removal, and participation in plant responses to adverse environmental stimuli remain largely unclear. Therefore, the aim of this study was to assess the influence of selected single stresses and combined stresses (i.e., Rhopalosiphum padi L. aphid infestation, drought, aphid infestation, and drought) and post-stress recovery on the contents of NO and peroxynitrite anion (ONOO⁻), as well as the levels of mRNA and protein nitration (i.e., the 8-nitroguanine and protein 3-nitrotyrosine amounts, respectively), in maize seedlings (Zea mays L.). Moreover, the expression patterns of the two tested genes (nos-ip, encoding nitric oxide synthase-interacting protein, and nr1, encoding nitrate reductase 1) involved in NO metabolism in maize plants were quantified. We identified significant intervarietal, time-course, and stress-dependent differences in the levels of the quantified parameters. Under the investigated stress conditions, the aphid-resistant Waza cv. seedlings were characterized by a higher and earlier NO accumulation and mRNA nitration level and an increased expression of the two target genes (nos-ip and nr1), compared to the aphid-susceptible Złota Karłowa cv. seedlings. Conversely, the Złota Karłowa plants responded with a greater elevation in the content of ONOO⁻ and protein 3-nitrotyrosine than the Waza cv. plants The multifaceted role of NO and its derivatives in maize plants challenged by single and combined stresses, as well as during post-stress recovery, is discussed. Full article

The bird cherry-oat aphid, Rhopalosiphum padi (L.), is an economically significant pest of pasture grasses, the latter being capable of hosting several fungal endophyte–perennial ryegrass symbiota rich in alkaloids and toxic to vertebrates and invertebrates. Measuring aphid feeding behaviour can provide insights into the effectiveness and mode of action of different fungal endophytes. This study investigated the effects of different Epichloë–perennial ryegrass symbiota on the feeding behaviour of R. padi using the electrical penetration graph technique while also assessing the aphid life history. In most cases, endophytes had significant feeding deterrence and paired fecundity and mortality effects. But, in some instances, endophytes with the highest aphid mortality did not significantly deter feeding, suggesting a more complicated scenario of interactions between the relative concentration of metabolites, e.g., host plant defence response metabolites and alkaloids, and/or physical changes to leaf morphology. Overall, this study sheds light on the mode of action of Epichloë endophytes against aphids and highlights the importance of Epichloë–perennial ryegrass symbiota in the management of insect pests such as aphids in pasture-based grazing systems. Full article

Hesperidin is a highly bioactive natural flavonoid whose role in ecological interactions is poorly known. In particular, the effects of hesperidin on herbivores are rarely reported. Flavonoids have been considered as prospective biopesticides; therefore, the aim of the present study was to examine the influence of hesperidin on the host plant selection behavior of three aphid (Hemiptera: Aphididae) species: Acyrthosiphon pisum Harrris, Rhopalosiphum padi (L.), and Myzus persicae (Sulz.). The aphid host plants were treated with 0.1% and 0.5% ethanolic solutions of hesperidin. Aphid probing behavior in the no-choice experiment was monitored using electropenetrography and aphid settling on plants in the choice experiment was recorded. The results demonstrated that hesperidin can be applied as a pre-ingestive, ingestive, and post-ingestive deterrent against A. pisum, as an ingestive deterrent against R. padi, and as a post-ingestive deterrent against M. persicae using the relatively low 0.1% concentration. While in A. pisum the deterrent effects of hesperidin were manifested as early as during aphid probing in peripheral plant tissues, in M. persicae, the avoidance of plants was probably the consequence of consuming the hesperidin-containing phloem sap. Full article

Essential oils (EOs), including those from the Asteraceae plants, have been shown to have promising insecticidal activity against a wide range of insect pests. Understanding the mechanism of action of EOs is one of the studied aspects. The present study aimed to evaluate the effect of essential oils from Achillea millefolium, Santolina chamaecyparissus, Tagetes patula and Tanacetum vulgare on the settling and probing behavior of the bird cherry-oat aphid (Rhopalosiphum padi L.). In addition, the effect of the oils on the activity of such enzymes as trypsin, pepsin and α- and β-glucosidase involved in the metabolism of proteins and sugars of the insects was examined. The leaf-choice bioassays demonstrated that the studied EOs limited aphid settling for at least 24 h after the treatment. The application of EOs also inferred with aphid probing behavior by reducing the total probing time and total duration of phloem sap ingestion. Aphids spent more time in the search phase due to an increase in the number and total duration of pathway phases. Moreover, the activity of the studied proteases and glucosidases significantly decreased in R. padi females exposed to the EOs. The enzyme inhibition varied depending on the applied oil and exposure time. Generally, the EOs with stronger deterrent activity also showed higher inhibitory effects. The results suggest that the tested EOs disrupt key digestive processes in R. padi which may be an important factor determining their aphicidal activity. Full article

Thiamethoxam, a second-generation neonicotinoid insecticide is widely used for controlling sap-sucking insect pests including Rhopalosiphum padi. The current study aimed to investigate the life-history parameters and feeding behavior of R. padi following treatments with sublethal concentrations of thiamethoxam. The lethal concentration 50 (LC₅₀) value of thiamethoxam against adult R. padi was 11.458 mg L⁻¹ after 48 h exposure. The sublethal concentrations of thiamethoxam (LC₅ and LC₁₀) significantly decreased the adult longevity, fecundity, and reproductive days in the directly exposed aphids (F₀ generation). In the progeny R. padi (F₁), the developmental durations and total prereproductive period (TPRP) were decreased while the adult longevity, fecundity, and reproductive days (RP_d) were increased at both thiamethoxam concentrations. The demographic parameters including the net reproductive rate (R₀), intrinsic rate of increase (r), and finite rate of increase (λ) were prolonged only at the LC₅ of thiamethoxam. The EPG results indicated that the sublethal concentrations of thiamethoxam increases the total duration of non-probing (Np) while reducing the total duration of E2 in directly exposed aphids (F₀). Interestingly, the E2 were significantly increased in the progeny generation (F₁) descending from previously exposed parental aphids (F₀). Overall, this study showed that thiamethoxam exhibited high toxicity against directly exposed individuals (F₀), while inducing intergenerational hormetic effects on the progeny generation (F₁) of R. padi. These findings provided crucial details about thiamethoxam-induced hormetic effects that might be useful in managing resurgences of this key pest. Full article