Showing papers on "Aphididae published in 2022"
TL;DR: In this article , the authors used correlation and multivariate regression modeling to detect relationships with insects at different spatial scales and found that more complex landscape configuration, particularly the amount of habitat edges, was associated with increased aphid and natural enemy abundance.
Abstract: Abstract Landscapes with more complex composition and configuration are generally expected to enhance natural enemy densities and pest suppression. To evaluate this hypothesis for an invasive aphid pest of sorghum, Melanaphis sorghi Theobald (Hemiptera: Aphididae), sampling in sorghum fields for aphids and natural enemies was conducted over two years in a southern U.S. coastal production region. Landscape composition and configuration of crop and noncrop elements were assessed using correlation and multivariate regression modeling to detect relationships with insects at different spatial scales. Significant models found more complex landscape configuration, particularly the amount of habitat edges, was associated with increased aphid and natural enemy abundance. Composition associated with noncrop habitats had the opposite effect. Numerical response of natural enemies was taxa dependent, with parasitism lower as landscape complexity increased, while predator numerical response was not affected by landscape complexity. These results indicate landscape complexity may increase both aphid and natural enemy abundance, but with decreasing parasitism and little association with predator numerical response. These relationships are likely contingent on overall environmental suitability to aphid population increase as results were less evident in the second year when average aphid abundance regularly exceeded the economic threshold. This study supports the importance of configuration, especially habitat borders, as a critical metric for determining pest-natural enemy dynamics within a large-scale cereal agroecosystem.
17 citations
TL;DR: Interestingly, it was found that A. gossypii collected from cotton plants showed higher tolerance to afidopyropen compared with individuals collected from the other host plants.
14 citations
TL;DR: In this article , the authors evaluated the susceptibility baseline of field populations of A. gossypii to the novel pyropene insecticide afidopyropen and found that the susceptibility of these populations to this newly commercialized insecticide is important for ensuring its continued efficacy.
13 citations
TL;DR: This study investigates the evolution of resistance to a new plant protection product, spirotetramat, following reported chemical control failures of Myzus persicae from Australia and demonstrates that resistance is associated with the previously reported mutation, A2226V in the target-site of spiroteramat, acetyl-CoA carboxylase.
Abstract: Abstract BACKGROUND Chemicals are widely used to protect field crops against aphid pests and aphid‐borne viral diseases. One such species is Myzus persicae (Sulzer), a global pest that attacks a broad array of agricultural crops and transmits many economically damaging plant viruses. This species has evolved resistance to a large number of insecticide compounds as a result of widespread and repeated chemical use in many parts of the world. In this study, we investigated the evolution of resistance to a new plant protection product, spirotetramat, following reported chemical control failures. RESULTS Our study provides clear phenotypic and genotypic evidence of spirotetramat resistance in populations of M. persicae from Australia. We show there is cross‐resistance to other insecticides within the same chemical group, namely spiromesifen and spirodiclofen. We also demonstrate that resistance is associated with the previously reported mutation, A2226V in the target site of spirotetramat, acetyl‐CoA carboxylase. Our genetic analysis found all resistant M. persicae populations belong to the same multi‐locus clonal type and carry the A2226V mutation, which appears to be inherited as a dominant trait in this species. CONCLUSION Our findings provide new insight into the resistance conferred by A2226V and have implications for the control of M. persicae in Australia and worldwide. A diagnostic assay developed in this study should serve as a valuable tool for future resistance monitoring and to support the implementation of pest management strategies. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
8 citations
TL;DR: The green peach aphid, Myzus persicae (Sulzer) is a significant global pest of a broad range of horticultural and grain crops as mentioned in this paper .
8 citations
TL;DR: Parasitism and predation contributed to aphid regulation on both hybrids, which may accrue multiple benefits leading to a more resilient sugarcane aphid management system.
Abstract: Abstract The sugarcane aphid, Melanaphis sacchari (Zehntner) (Hemiptera: Aphididae), is an invasive sorghum pest that has threatened over 90% of North American sorghum production. Resident parasitoids, coccinellids, syrphids, and lacewings prey on this aphid. Our objective was to compare and estimate parasitoid and predator suppression of sugarcane aphids placed on resistant and susceptible hybrids in a field setting using natural enemy exclusion cages. During 2018 and 2019 along the Texas Gulf Coast and Central Oklahoma, three natural enemy exclusion treatments—no exclusion (full access for parasitoids and predators), partial exclusion (access limited to parasitoids), and complete exclusion (excludes parasitoids and predators)—were used. The parasitoid Aphelinus nigritus Howard (Hymenoptera: Aphelinidae) accounted for 90% of recovered natural enemies. In 2018, aphid suppression attributable to A. nigritus was ca. 95% on the resistant hybrids and 80% on the susceptible hybrids when comparing aphid counts from complete and partial exclusion treatments, while few predators were observed. In 2019, aphid suppression was attributed to a combination of predation and parasitism. Relatively more predators were recorded at both sites, accounting for 14% to 33% of specimens recovered in the no exclusion treatment. Aphid suppression attributed to predators and parasitoids ranged from 85% on aphid-resistant hybrids and 27% on susceptible hybrids in south Texas and >95% on both hybrids in Oklahoma when comparing aphid abundance in the complete and no exclusion treatments. Parasitism and predation contributed to aphid regulation on both hybrids, which may accrue multiple benefits leading to a more resilient sugarcane aphid management system.
6 citations
TL;DR: In this article , the effects of sub-lethal concentrations of afidopyropen on the biological characteristics of A. gossypii were evaluated and it was shown that a sub-lucine concentration (LC10) significantly decreased adult longevity, fecundity and oviposition days of female adults in both F0 and F1 generations.
6 citations
TL;DR: In this paper , an environmentally friendly and effective mycoinsecticide from a local fungal isolate against M. persicae nymphs, Beauveria bassiana (KTU-24), was identified as the most promising isolate.
Abstract: Long-term and intensive use of synthetic insecticides to control the green peach aphid, Myzus persicae (Homoptera: Aphididae) in agricultural production in the world has resulted in pest resistance and environmental pollution. The aim of the study was to develop an environmentally-friendly and effective mycoinsecticide from a local fungal isolate against M. persicae. According to the results of the screening experiments using 15 isolates (6 × Metarhizium, 5 × Beauveria, 2 × Isaria, 2 × Lecanicillium) at 1 × 107 conidia ml−1 concentrations and the dose–response experiments at 1 × 105 –1 × 109 conidia ml−1 concentrations against M. persicae nymphs, Beauveria bassiana (KTU-24) was identified as the most promising isolate. The strain KTU-24 is also had tolerance to ecological conditions such as temperature, and UV-B. KTU-24 with advantageous and superior properties was used to develop a test mycoinsecticide. Mass production of spores by KTU-24 was conducted out by liquid-state fermentation using liquid medium. Spores harvested from the sporulated biomass were used to develop an oil-based mycoinsecticide, and the product was designated as AFIDISIDAL-OD Bbas-TR61. The product had lethal effect on M. persicae nymphs at a concentration of 1 × 108 conidia ml−1 in leaf-disc (82.5%) and pot (84.33%) experiments in a climate chamber. The oil-based mycoinsecticide developed in this study could be profitable when used in aphid-IPM prgrams by reducing crop loss and synthetic pesticides use.
5 citations
TL;DR: The present study evaluated the insecticidal activity of Citrus aurantium and C. reticulata peel EO at different concentrations and with different exposure periods to pomegranate and grapevine aphids, Aphis punicae and A. illinoisensis via the topical application method under laboratory conditions to offer a potential tool to control the two aphid species.
Abstract: Aphids are serious pests of a wide range of agricultural crops, including pomegranates and grapevines. In addition, due to the negative environmental impacts of chemical insecticides, these pests are developing important resistance against aphicides. Therefore, one alternative method to control aphids is the use of essential oils (EO). The present study aimed to evaluate the insecticidal activity of Citrus aurantium and C. reticulata peel EO at different concentrations and with different exposure periods to pomegranate and grapevine aphids, Aphis punicae and A. illinoisensis via the topical application method under laboratory conditions. The results reveal that C. aurantium L. EO had greater toxicity against pomegranate and grapevine aphids, with LC50 of 0.37 and 0.82 μL/mL, respectively, at 48 h after application. The highest repellence effect was estimated for C. aurantium EO, at 2.5 μL/cm2, on A. punicae, with a value of 100% after an exposure time of 3 h, in contrast to the 88% repellence estimated for A. illinoisensis. The GC-MS investigation of both essential oils identified limonene, 3-carene, pinene, and p-cymene as active substances that could be attributed to the effects observed. Overall, our results offer a potential tool to control the two aphid species and could help in the development of integrated insect management in pomegranate and grapevine fields.
5 citations
TL;DR: In this paper , the effects of cucumber inoculation with this fungus on plant metabolites, and the physiological consequences for aphids that fed on these plants were investigated, with both the commercial formulation of B. bassiana, ‘Naturalis®-L’, at the recommended concentration of 1.5 ml / L (yielding a spore concentration of 2.3 × 107 CFU per ml), and with a similar concentration of the isolated fungal strain.
Abstract: The entomopathogen Beauveria bassiana (Bals.) Vuill. (Ascomycota: Hypocreales) can colonize plants endophytically and stimulate the production of secondary plant metabolites with anti-herbivore activities. We assayed the topical virulence of B. bassiana to Aphis gossypii Glover (Hemiptera: Aphididae), the effects of cucumber inoculation with this fungus on plant metabolites, and the physiological consequences for aphids that fed on these plants. Assays were conducted with both the commercial formulation of B. bassiana, ‘Naturalis®-L’, at the recommended concentration of 1.5 ml / L (yielding a spore concentration of 2.3 × 107 CFU per ml), and with a similar concentration of the isolated fungal strain. Topical application of 0.03 ml of solution per cm2, or 1 × 103 CFU, caused 100% mortality to A. gossypii adults after seven days, whether Naturalis®-L or the isolate alone was used. The fungus grew endophytically into foliage when sprayed on cucumbers at the 2-leaf stage and concentrations of alkaloids, fl avonoids, phenols, hydrogen peroxide, and total chlorophyll were higher than in control plants 28 days after inoculation. Malondialdehyde content, plant growth, and total yield were unaffected by B. bassiana inoculation. Aphids fed on B. bassiana-inoculated plants for 24 h had reduced activities of detoxifying enzymes (glutathione-S-transferase, carboxylesterase, and acetylcholinesterase) compared to controls. Activities of digestive enzymes, (lipase, α-amylase, α-glucosidase, and aminopeptidase) were reduced in aphids from inoculated plants, which exhibited higher activities of superoxide dismutase, ascorbate peroxidase, and phenoloxidase, but lower catalase activity. Energy reserves (lipids, protein, and glycogen) were lower in aphids from inoculated plants, and they exhibited reduced fecundity, longevity, and reproductive periods, and a 50% reduction in the LC50 of pirimicarb. Thus, in addition to causing direct pathogenicity, inoculation of plants with B. bassiana negatively impacted A. gossypii physiology and reproductive performance and could usefully complement other strategies for managing cotton aphids on greenhouse cucumber. * Corresponding author; e-mail: jpmi@ksu.edu INTRODUCTION The cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae) is a polyphagous cosmopolitan pest of numerous fi eld and greenhouse crops (Ebert & Cartwright, 1997). It has the capacity for rapid population growth, causing direct feeding damage to host plants and transmitting various plant viruses (Deguine et al., 2017). Management of cotton aphids has conventionally relied on the use of synthetic insecticides (Kandil et al., 2017), which has resulted in the aphids evolving resistance to various insecticidal modes of action, and generated a need for alternative management tactics (Wang et al., 2007; Carletto et al., 2010). Eur. J. Entomol. 119: 1–11, 2022 doi: 10.14411/eje.2022.001
5 citations
TL;DR: In this paper , the authors investigated predation and development of Harmonia axyridis foraging on Acyrthosiphon pisum at four different temperatures (15, 20, 25, and 30 °C).
TL;DR: In this article , the authors assessed 44 Musa germplasm of different A and B genome composition for the performance of banana aphids under semicontrolled environmental screenhouse conditions and in a field trial established in a BBTD endemic location.
Abstract: Banana bunchy top disease (BBTD), caused by the banana bunchy top virus (BBTV, genus Babuvirus), is the most destructive viral disease of banana and plantain (Musa spp.). The virus is transmitted persistently by the banana aphid, Pentalonia nigronervosa Coquerel (Hemiptera: Aphididae). While research efforts have focused on screening Musa genotypes for BBTD resistance, comparatively little work has been carried out to identify resistance to banana aphids. This study assessed 44 Musa germplasm of different A and B genome composition for the performance of banana aphids under semicontrolled environmental screenhouse conditions and in a field trial established in a BBTD endemic location. In the screenhouse, the AA diploid Calcutta 4 had the lowest apterous aphid density per plant (9.7 ± 4.6) compared with AAB triploid Waema, which had the highest aphid densities (395.6 ± 20.8). In the field, the highest apterous aphid density per plant (29.2 ± 6.7) occurred on the AAB triploid Batard and the lowest (0.4 ± 0.2) on the AA diploid Pisang Tongat. The AA diploid Tapo was highly susceptible to BBTD (100% infection) compared with the genotypes Balonkawe (ABB), PITA 21 (AAB), Calcutta 4 (AA), and Balbisiana Los Banos (BB), which remained uninfected. The Musa genotypes with apparent resistance to BBTD and least susceptibility to aphid population growth provide options for considering aphid and BBTD resistance in banana and plantain breeding programs.
TL;DR: In this article , different maize fields were sampled to test corn leaf aphid, Rhopalosiphum maidis, populations in terms of total and endosymbiotic bacterial diversity.
Abstract: In this study, different maize fields cultivated under different management systems were sampled to test corn leaf aphid, Rhopalosiphum maidis, populations in terms of total and endosymbiotic bacterial diversity. Corn leaf aphid natural populations were collected from traditionally managed maize fields grown under high agricultural and natural landscape diversity as well as conventionally treated high-input agricultural fields grown in monoculture and with fertilizers use, hence with low natural landscape diversity. Total bacterial community assessment by DNA sequencing was performed using the Illumina MiSeq platform. In total, 365 bacterial genera were identified and 6 endosymbiont taxa. A high abundance of the primary endosymbiont Buchnera and secondary symbionts Serratia and Wolbachia were detected in all maize crops. Their frequency was found to be correlated with the maize management system used, probably with fertilizer input. Three other facultative endosymbionts (“Candidatus Hamiltonella”, an uncultured Rickettsiales genus, and Spiroplasma) were also recorded at different frequencies under the two management regimes. Principal components analyses revealed that the relative contribution of the obligate and dominant symbiont Buchnera to the aphid endosymbiotic bacterial community was 72%, whereas for the managed system this was only 16.3%. When facultative symbionts alone were considered, the effect of management system revealed a DNA diversity of 23.3%.
TL;DR: It is shown for the first time that cannabis aphid is an efficient vector of PVY to both hemp and potato, and that virus infection and host plant suitability affect feeding behaviors of the Cannabis aphid in ways which may increase virus transmission.
Abstract: Abstract Aphids are the most prolific vectors of plant viruses resulting in significant yield losses to crops worldwide. Potato virus Y (PVY) is transmitted in a non-persistent manner by 65 species of aphids.With the increasing acreage of hemp (Cannabis sativa L.) (Rosales: Cannabaceae) in the United States, we were interested to know if the cannabis aphid (Phorodon cannabis Passerini) (Hemiptera: Aphididae) is a potential vector of PVY. Here, we conduct transmission assays and utilize the electrical penetration graph (EPG) technique to determine whether cannabis aphids can transmit PVY to hemp (host) and potato (non-host) (Solanum tuberosum L.) (Solanales: Solanaceace). We show for the first time that the cannabis aphid is an efficient vector of PVY to both hemp (96% transmission rate) and potato (91%) using cohorts of aphids. In contrast, individual aphids transmitted the virus more efficiently to hemp (63%) compared to potato (19%). During the initial 15 min of EPG recordings, aphids demonstrated lower number and time spent performing intracellular punctures on potato compared to hemp, which may in part explain low virus transmission to potato using individual aphids. During the entire 8-hour recording, viruliferous aphids spent less time ingesting phloem compared to non-viruliferous aphids on hemp. This reduced host acceptance could potentially cause viruliferous aphids to disperse thereby increasing virus transmission. Overall, our study shows that cannabis aphid is an efficient vector of PVY, and that virus infection and host plant suitability affect feeding behaviors of the cannabis aphid in ways which may increase virus transmission.
30 Mar 2022
TL;DR: In this paper , the effects of potassium silicate (K2SiO3) on the survival, development and reproduction of Aphis gossypii at various life stages were tested under laboratory conditions.
Abstract: Induced plant resistance is an important component of pest control. Therefore, effects of potassium silicate (K2SiO3) on the survival, development and reproduction of Aphis gossypii Glover at various life stages were tested under laboratory conditions. Efficacy of foliar spraying with K2SiO3 compared to lambda-cyhalothrin (LCH) against the field strain of A. gossypii third nymphal instar under greenhouse conditions as well as its impacts on the activity of antioxidant enzymes were also evaluated. In laboratory studies, K2SiO3 (LC50 = 58.21 mg L) was less toxic than LCH (LC50 = 44.32 mg L) against A. gossypii first nymphal instar after 48 h treatment. There was no significant difference in the developmental duration of total nymphal stages among the three treatment concentrations (LC10, LC25 and LC50) and the control. Treatments with K2SiO3 significantly reduced the longevity and fecundity of adult aphids. Reduction percentages of A. gossypii field strain after feeding on cotton leaves sprayed with K2SiO3 were 47.1 and 55.0 % at 100 and 200 mg L, respectively, compared to 67.9 and 77.5% in LCH. The higher levels of catalase and polyphenol oxidase enzymes activities was observed at 24 h with percentages 68.16 and 32.74%, respectively, compared to the control, then declined and reached to minimum value at 96 h. However, peroxidase enzyme activity was increased with percentage 59.72 % at 12 h and decreased to reach minimum value at 48 h. This study could introduce promising plant resistance inductors for use in integrated pest management of A. gossypii on cotton plant.
TL;DR: In this paper , the authors compared the effectiveness of various plant-based extracts/seed oils (SO) against A. craccivora and other insect pests, including Triadica sebifera.
Abstract: Aphid, Aphis craccivora Koch (Hemiptera: Aphididae), is a major sap-sucking insect pest of leguminous crops and also transmits plant viruses, leading to economic yield loss. Indiscriminate and repeated use of insecticides for control of aphid leads to the development of resistance, and is harmful to the environment, non-target organisms, etc. Plant-based extracts/seed oils (SO) are the best alternatives to insecticides. Insecticidal activities of Triadica sebifera have not been reported against A. craccivora and other insect pests to date. In the current study, the main objective was to study the insecticidal activities of leaf/bark extracts/fractions, seed oil, isolated compounds, and their combinations against A. craccivora. Results showed that, among the extracts, ethanolic bark extract 80% (LC50 = 5115.98 mg/L) was more effective against A. craccivora. Among fractions, the n-hexane fraction of leaves (LC50 = 425.73 mg/L) and the ethyl acetate fraction of bark (LC50 = 813.45 mg/L) were promising. Among compounds, gallic acid was the most effective (LC50 = 1303.68 mg/L) compared to shikimic acid and quercetin. SO (LC50 = 850.94 mg/L) was superior compared to extracts/fractions/compounds. All the combinations showed toxicity and synergistic activity. Leaf/bark extracts and SO significantly inhibited the AChE and GST activity in A. craccivora. Based on field bio-efficacy, the leaf extract/SO or their combinations can be recommended for the control of aphids.
TL;DR: Life history analysis suggests that there are no negative pleotropic effects associated with the pyrethroid resistance in the clonal A. glycines lines used in this study, and the potential impact of these results on efficacies of insecticide resistance management (IRM) and integrated pest management (IPM) plans directed at delaying the spread of pyrethoid‐resistant A. glyines.
Abstract: Abstract BACKGROUND Foliar application of insecticides is the main strategy to manage soybean aphid, Aphis glycines (Hemiptera: Aphididae), in the northcentral United States. Subpopulations of A. glycines have multiple nonsynonymous mutations in the voltage‐gated sodium channel (vgsc) genes that are associated with pyrethroid resistance. We explored if fitness costs are associated with phenotypes conferred by vgsc mutations using life table analyses. We predicted that there would be significant differences between pyrethroid susceptibility and field‐collected, parthenogenetic isofemale clones with differing, nonsynonymous mutations in vgsc genes. RESULTS Estimated resistance ratios for the pyrethroid‐resistant clones ranged from 3.1 to 37.58 and 5.6 to 53.91 for lambda‐cyhalothrin and bifenthrin, respectively. Although life table analyses revealed some biological and demographic parameters to be significantly different among the clonal lines, there was no association between levels of pyrethroid resistance and a decline in fitness. By contrast, one of the most resistant clonal lines (SBA‐MN1‐2017) had a significantly higher finite rate of increase, intrinsic rate of increase and greater overall fitness compared to the susceptible control and other pyrethroid‐resistant clonal lines. CONCLUSIONS Our life history analysis suggests that there are no negative pleotropic effects associated with the pyrethroid resistance in the clonal A. glycines lines used in this study. We discuss the potential impact of these results on efficacies of insecticide resistance management (IRM) and integrated pest management (IPM) plans directed at delaying the spread of pyrethroid‐resistant A. glycines.
TL;DR: In this article , the toxicity of two bacteria, Photorhabdus luminescens and X. bovienii, symbionts of entomopathogenic nematodes, were tested in the laboratory against the multicolored Asian lady beetle, Harmonia axyridis, the black pecan aphid, Melanocallis caryaefoliae, and the blackmargined aphid Monellia caryella.
TL;DR: In this article , the authors evaluated the insecticidal effect of contact by fumigation of pure molecules of four commercial fatty acids (palmitic, stearic, pentadecanoic, and linoleic acids), the phytosterol β-sitosterol, and the flavonoid rutin.
TL;DR: Genotyping of aphid samples with microsatellite markers revealed that the super-clone predominated in the U.S. in 2019 and 2020 and Brazil in 2020 and is also present on sorghum within Brazil.
Abstract: Simple Summary Melanaphis sorghi has been a perennial economically important pest to U.S. sorghum since 2013. Previous research has shown its recent infestation on sorghum has been spreading as a super-clone, a highly abundant clone that is distributed over a large geographic area and persists over time, in the U.S. To continuously monitor the genotypes present in the U.S. and to determine the genotype present in Brazil on sorghum, Melanaphis spp. were collected in 2019 and 2020. Genotyping of aphid samples with microsatellite markers revealed that the super-clone predominated in the U.S. in 2019 and 2020 and Brazil in 2020. Thus, the M. sorghi super-clone remains in the U.S. on sorghum, Johnsongrass, and giant miscanthus and is present in Brazil on sorghum. Abstract Melanaphis sorghi (Hemiptera: Aphididae), are an economically important pest to sorghum in the Americas. Previous studies have found that a super-clone that belongs to multilocus lineage (MLL)-F predominated in the U.S. from 2013 to 2018 and uses multiple hosts besides sorghum. In contrast, previous studies found that aphids in South America belong to MLL-C, but these studies only examined aphids collected from sugarcane. In this study we sought to determine if the superclone persisted in the U.S. in 2019–2020 and to determine the MLL of aphids found on sorghum in the largest country in South America, Brazil. Melanaphis spp. samples (121) were collected from the U.S. in 2019–2020 and Brazil in 2020 and were genotyped with 8–9 Melanaphis spp. microsatellite markers. Genotyping results showed that all samples from the U.S. in 2019 and Brazil in 2020 had alleles identical to the predominant superclone. Of the 52 samples collected in the U.S. in 2020, 50 samples were identical to the predominant super-clone (multilocus lineage-F; M. sorghi), while two samples from Texas differed from the super-clone by a single allele. The results demonstrated that the super-clone remains in the U.S. on sorghum, Johnsongrass, and giant miscanthus and is also present on sorghum within Brazil.
TL;DR: Based on the results of the study, it looked like endogenous Steinernema-associated EPB could be used directly as a biocontrol agent for A. punicae and A. illinoisensis.
Abstract: The current work is aimed at isolating and identifying new Entomopathogenic bacterium (EPB) strains associated with Steinernema feltiae and assessing the EPB’s biocontrol potential on Aphis punicae and Aphis illinoisensis adults in the laboratory. From S. feltiae, five bacterial isolates were isolated and molecularly characterized. Lysinibacillus xylanilyticus strain TU-2, Lysinibacillus xylanilyticus strain BN-13, Serratia liquefaciens strain TU-6, Stenotrophomonas tumulicola strain T5916-2-1b, and Pseudochrobactrum saccharolyticum strain CCUG are the strains. Pathogenicity tests demonstrated that bacterial cells were more toxic against the two aphid species than bacterial cell-free supernatants. S. tumulicola strain T5916-2-1b cells and filtrate were reported to have the strongest potential to kill A. punicae and A. illinoisensis individuals within 6 h after treatment, with 100% mortality of both insects 24 and 48 h after treatment. Based on the results of the study, it looked like endogenous Steinernema-associated EPB could be used directly as a biocontrol agent for A. punicae and A. illinoisensis.
TL;DR: In this paper , the authors employed toxicity bioassays and electrical penetration graph (EPG) methodology to compare toxicity and quantify changes to feeding behavior and toxicity of A. gossypii after exposure to commercialized aphicides.
TL;DR: Results suggest that planting a host plant resistant cultivar and the integration of natural enemies with insecticide control methods in the management of M. sorghi is central to the development of an effective pest management strategy against this invasive pest.
Abstract: The invasive Melanaphis sorghi (Theobald; =Melanaphis sacchari Zehntner) is a serious pest of sorghum production in the southern USA. Demonstration of technologies that provide effective control is key to management of this pest. Here, we investigated the effect of host plant resistance (resistant cultivar: DKS37-07 and susceptible cultivar: DKS53-53) and a single foliar insecticide (flupyradifurone: Sivanto Prime) application on M. sorghi infestations and the role of natural enemy populations in grain sorghum production across five locations in four states in southeastern USA. Foliar insecticide application significantly suppressed M. sorghi infestations on both the resistant and susceptible sorghum cultivars across all locations. Planting the host plant resistant cultivar (DKS37-07) significantly reduced aphid infestation across all locations. Plant damage ratings did not vary widely, but there was generally a positive association between aphid counts and observed plant damage, suggesting that increasing aphid numbers resulted in corresponding increase in plant damage. Planting a host plant resistant cultivar and foliar insecticide application generally preserved grain yield. Both sorghum hybrids supported an array of different life stages of natural enemies (predators [lady beetle larvae and adults; hoverfly larvae and lacewing larvae] and parasitoids [a braconid and aphelinid]) for both the sprayed and non-sprayed treatments. We found a strong and significant positive relationship between the natural enemies and the M. sorghi infestation. Results suggest that planting a host plant resistant cultivar and the integration of natural enemies with insecticide control methods in the management of M. sorghi is central to the development of an effective pest management strategy against this invasive pest.
TL;DR: A simple empirical colour choice model was developed and optimized for spring migrants of different aphid species which confirmed and explained the yellow preference of these insects, and showed that aphid visual preference would be dependent on the plants’ nutritional status, with lower nitrogen input being associated with stronger preference.
Abstract: Aphids are economically and ecologically important herbivorous insects. A critical step in their life cycle is the visually guided host finding behaviour. To elucidate the role of colour in host finding of aphid spring migrants we conducted large colour trap experiments in the field and analysed aphid catch data, using trap spectral reflectance data as input. Based on known and putative photoreceptor sensitivities we developed and optimized a simple empirical colour choice model for spring migrants of different aphid species which confirmed and explained the yellow preference of these insects. In a further step, we applied multivariate statistical methods to behavioural and reflectance data, but without data on photoreceptor sensitivities, to find the wavelengths of greatest importance for the aphids' behavioural responses. This analysis confirmed the position of the green photoreceptor peak previously obtained independently with electrophysiological methods. In a final step, we applied the colour preference model to a dataset of leaf spectra. This showed that aphid visual preference would be dependent on the plants’ nutritional status, with lower nitrogen input being associated with stronger preference, despite known benefits of high nitrogen levels for aphid reproduction and fitness. Ecological and evolutionary implications of these results are discussed. This article is part of the theme issue ‘Understanding colour vision: molecular, physiological, neuronal and behavioural studies in arthropods’.
TL;DR: In this article , the authors used headspace solid microextraction (HS-SPME) and GC-MS to investigate volatile organic compounds (VOCs) from cabbage plants infested and uninfested with green peach aphid Myzus persicae.
Abstract: Headspace solid microextraction (HS-SPME) and GC-MS were used to investigate volatile organic compounds (VOCs) from cabbage plants infested and uninfested with green peach aphid Myzus persicae. The HS-SPME combined with GC-MS analysis of the volatiles described the differences between the infested and uninfested cabbage. Overall, 28 compounds were detected in infested and uninfested cabbage. Some VOCs released from infested cabbage were greater than uninfested plants and increased the quantity of the composition from infested plants. According to the peak area from the GC-MS analysis, the VOCs from infested cabbage consisted of propane, 2-methoxy, alpha- and beta pinene, myrcene, 1-hexanone, 5-methyl-1-phenyl-, limonene, decane, gamma-terpinen and heptane, 2,4,4-trimethyl. All these volatiles were higher in the infested cabbage compared with their peak area in the uninfested cabbage. The results of the study using a Y-shape olfactometer revealed that the VOCs produced by infested cabbage attracted Myzus persicae substantially more than uninfested plants or clean air. The percentage of aphid choice was 80% in favor of infested cabbage; 7% were attracted to the clean air choice and uninfested plants. A total of aphids 7% were attracted to clean air. Comparing between infested and uninfested cabbage plants, the aphid was attracted to 63% of the infested cabbage, versus 57% of the uninfested cabbage. The preferences of Aphidus colemani and Aphelinus abdominalis to the infested or uninfested plants with M. persicae and compared with clean air indicated that parasitoids could discriminate the infested cabbage. Both parasitoids significantly responded to the plant odor and were attracted to 86.6% of the infested cabbage plants.
TL;DR: In this paper , the individual and combined effect of eight insecticides and the entomopathogenic fungi, Metarhizium anisopliae (Metschin), against the cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), under laboratory conditions was assessed.
Abstract: Aphids are major pests affecting cereals, vegetables, fruit, forestry and horticultural produce. A multimodal approach may be an effective route to controlling this prolific pest. We assessed the individual and combined effect of eight insecticides and the entomopathogenic fungi, Metarhizium anisopliae (Metschin.) against the cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), under laboratory conditions. Six of the insecticides tested were found to be highly compatible (flonicamid, imidacloprid, nitenpyram, dinotefuran, pyriproxyfen and spirotetramat), showing positive integration with the fungus and were selected for bioassays. The combination mixtures (1:1 ratio of M. anisopliae: insecticide) were significantly more toxic to A. gossypii than individual treatments. Maximum mortality (91.68%) of A. gossypii was recorded with combination of flonicamid and M. anisopliae (2.4 × 106 cfu/ml) 72 h after application. While minimum mortality (17.08%) was observed with the individual treatment of M. anisopliae (2.4 × 106 cfu/ml). The insecticides revealed toxicity consistent with their compatibility with M. anisopliae, ranking for efficacy exactly as they did for compatibility. In addition, the synergy factor (SF) and co-toxicity coefficient (CTC) values indicated synergistic interactions at different time intervals. The synergistic efficacy revealed the potential of fungus-insecticide integration against sucking insect pests.
TL;DR: In this article , the resistance of A. gossypii to various forms of commonly used pesticides has seriously threatened the safety of the cotton production, and therefore, it is necessary to rotate or mix afidopyropen with other insecticides in order to inhibit the development of afidopen resistance in field populations.
Abstract: The resistance of cotton aphids to various forms of commonly used pesticides has seriously threatened the safety of the cotton production. Afidopyropen is a derivative of microbial metabolites with pyropene insecticide, which has been shown to be effective in the management of Aphis gossypii. Several field populations of Aphis gossypii were collected from the major cotton-producing regions of China from 2019 to 2021. The resistance of these populations to afidopyropen was estimated using the leaf-dipping method. The LC50 values of these field populations ranged from 0.005 to 0.591 mg a.i. L−1 in 2019, from 0.174 to 4.963 mg a.i. L−1 in 2020 and from 0.517 to 14.16 mg a.i. L−1 in 2021. The resistance ratios for all A. gossypii populations ranged from 0.03 to 3.97 in 2019, from 1.17 to 33.3 in 2020 and from 3.47 to 95.06 in 2021. The afidopyropen resistance exhibited an increasing trend in the field populations of Cangzhou, Binzhou, Yuncheng, Kuerle, Kuitun, Changji and Shawan from 2019 to 2021. This suggests that the resistance development of the cotton aphid to afidopyropen is inevitable. Therefore, it is necessary to rotate or mix afidopyropen with other insecticides in order to inhibit the development of afidopyropen resistance in field populations.
TL;DR: In this article , a large-scale relationship between temperature and myzus persicae observations across the UK and apply this to a very large ensemble of climate model simulations, which better sample the variability in climate, to quantify the current likelihood of extreme early M. persicaes' flight across UK.
Abstract: Myzus persicae (Sulzer, Hemiptera: Aphididae) is a major global crop pest; it is the primary aphid vector for many damaging viruses and has developed resistance to most insecticides. In temperate regions, the risk of widespread crop infection and yield loss is heightened following warm winters, which encourage rapid population growth and early flight. Estimates of the frequency and magnitude of warm winters are, therefore, helpful for understanding and managing this risk. However, it is difficult to quantify the statistical distribution of climate events, particularly extremes, because climate observations represent just a small sample of the possible climate variations in a region. The purpose of this study was to establish a large-scale relationship between temperature and M. persicae observations across the UK and apply this to a very large ensemble of climate model simulations, which better sample the variability in climate, to quantify the current likelihood of extreme early M. persicae flight across the UK. The timing of M. persicae flight was shown to be significantly related to January-February mean temperature, where a 1°C warmer/cooler temperature relates to about 12 d earlier/later flight. Climate model simulations predict 40% likelihood of experiencing a year with unprecedented early M. persicae flight during the next decade in the UK. Results from this method can help crop managers assess the long-term viability of crops and management practices across the UK and provide early warning information for targeting pest surveillance activities on the locations and timings at highest risk of early M. persicae flight.
TL;DR: The new species is a member of the Geoica utricularia group and morphologically resembles Geoica wertheimae Brown Blackman, 1994, and makes coral-shaped galls, while all congeners produce spherical galls.
Abstract: Geoica inbari sp. nov., living on Pistacia palaestina Boiss. (Anacardiaceae), is described based on apterous fundatrigeniae, fall migrants, embryos of apterous exules within fall migrants (fundatrispuriae) and the first instar larva of an apterous exule borne by a fall migrant, collected in the Mount Hermon area of Northern Israel. The new species differs from all other known Geoica species in its mitochondrial DNA, and from those known from Pistacia by the shape of the galls. It makes coral-shaped galls, while all congeners produce spherical galls. The new species is a member of the Geoica utricularia group and morphologically resembles Geoica wertheimae Brown Blackman, 1994.
TL;DR: The results demonstrate the deterrent effects of MEJA‐induced cotton plants on sucking pests and suggest that MEJA could be exploited as a non‐toxic pest management tool.
Abstract: Methyl jasmonate (MEJA), a volatile organic compound, can induce plant defenses, thereby contributing to repelling insect pests and attracting their natural enemies. In 2013 and 2014, the influence of three exogenous MEJA doses (0.88, 1.76, and 3.55 mM) under field conditions was investigated on the abundance of the cotton pests Thrips tabaci Lindeman (Thysanoptera: Thripidae), Empoasca decipiens Paoli (Hemiptera: Cicadellidae), and Aphis gossypii Glover (Hemiptera: Aphididae), as well as of the predators Coccinella septempunctata L. (Coleoptera: Coccinellidae), Aeolothrips intermedius Bagnall (Thysanoptera: Aeolothripidae), and Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae). The MEJA treatments were performed at three cotton plant growth stages: 6–8 true leaves‐early squaring, square bud, and boll forming. The abundances of A. gossypii, T. tabaci, and E. decipiens varied considerably among strata and growing seasons and between experimental years, but overall they were lower on MEJA‐treated cotton plants than on control plants. The population density of A. intermedius and C. septempunctata did not differ between MEJA‐treated and control plants, whereas the intermediate MEJA concentration had an attractive but inconsistent effect on C. carnea. Most of the insect pests and predators showed a preference for specific plant strata. The abundance of T. tabaci was higher in earlier plant growth stages, whereas A. gossypii and E. decipiens were more abundant in later growth stages. Our results demonstrate the deterrent effects of MEJA‐induced cotton plants on sucking pests and suggest that MEJA could be exploited as a non‐toxic pest management tool. Possible mechanisms underlying the effectiveness of MEJA‐mediated cotton plant responses to insect pests are discussed.