Showing papers on "Aphididae published in 2018"
TL;DR: One of very few reports of the compatible use of endophytic fungal entomopathogens with other biological control agents, particularly parasitoids, for aphid suppression under controlled greenhouse conditions as part of an Integrated Pest Management (IPM) approach is presented.
80 citations
TL;DR: Biological efficiency of botanical insecticides was determined that were obtained from Pongamia against Spodoptera littoralis, Myzus persicae and Tetranychus urticae on greenhouse plants and the highest concentration caused 100% mortality.
Abstract: Pavela R. (2009): Effectiveness of some botanical insecticides against Spodoptera littoralis Boisduvala (Lepidoptera: Noctudiae), Myzus persicae Sulzer (Hemiptera: Aphididae) and Tetranychus urticae Koch (Acari: Tetranychidae). Plant Protect. Sci., 45: 00–00. Abstract: Biological efficiency of botanical insecticides was determined that were obtained from Pongamia Biological efficiency of botanical insecticides was determined that were obtained from Pongamia glabra, azadirachta indica and Chrysanthemum cinerariifolium against Spodoptera littoralis, Myzus persicae and Tetranychus urticae on greenhouse plants. In all the tested extracts, the highest concentration caused 100% mortality. In the other tested concentrations, a conclusive difference in efficiency was found; on day 12 after application, the highest efficiency was determined for M. persicae pongam oil, for T. urticae and S. littoralis
61 citations
TL;DR: It is demonstrated that a commercially available resistant sorghum variety provides the most robust protection against this pest in the central High Plains, and an already present assemblage of aphid predators recruits readily to aphid-infested Sorghum and is likely to provide important biological control services particularly in resistant sorks.
46 citations
TL;DR: The initial detection and establishment of D. noxia in Australia in 2016 is documented, these are the first records for this genus from South Australia, Victoria and New South Wales, and the potential impact of this aphid on Australian cereal production is discussed.
Abstract: Invasive pest species pose a major threat to agricultural production around the world. Until recently, the Russian wheat aphid, Diuraphis noxia Kurdjumov, a major pest of wheat and barley crops worldwide, was considered a high-priority exotic pest threat to the Australian grains industry. Here, we document the initial detection and establishment of D. noxia in Australia in 2016. These are the first records for this genus from South Australia, Victoria and New South Wales. Morphological and molecular information is presented for confirmed diagnosis of the species based on voucher specimens. Known distribution data are provided, along with a list of Poaceae hosts on which D. noxia has been recorded, and a brief description of the typical damage symptoms caused by these aphids. The potential impact of this aphid on Australian cereal production is discussed, and we identify research areas required to underpin future management of this new threat to the Australian cereal industry.
41 citations
TL;DR: This study collected data on the development, survival, fecundity, and proportion of apterous and alate forms of green peach aphid reared on five commercial pepper cultivars and compared differences in the population growth rate of M. persicae on different pepper cultivARS.
Abstract: The green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), is a major pest of pepper. In this study, we collected data on the development, survival, fecundity, and proportion of apterous and alate forms of green peach aphid reared on five commercial pepper cultivars (Amiral, Erciyes, Mert, Mertcan, and Naz) at 25 ± 1°C, 60 ± 5% RH, and a photoperiod of 16:8 (L:D) h. We analyzed the life history raw data by using the age-stage, two-sex life table. The shortest development time (6.66 days) and highest fecundity (62.68 individuals) occurred on the Erciyes cultivar. The highest intrinsic rate of increase (r = 0.332 d−1), finite rate of increase (λ = 1.394 d−1), net reproductive rate (R0 = 62.7 offspring) and shortest mean generation time (T = 12.45 d) also occurred on the Erciyes cultivar; while the lower fitness occurred on the Amiral, Mertcan and Naz cultivars. Our results compared differences in the population growth rate of M. persicae on different pepper cultivars. This information will be useful to individuals working in pest management programs particularly those involving M. persicae.
40 citations
TL;DR: The results indicated that EPF and botanical extracts (neem or eucalyptus) caused significant reduction in survival and fecundity of S. avenae and they may be used as promising natural alternatives to synthetic insecticides against the wheat aphid species.
Abstract: Wheat aphid, Sitobion avenae (Fab.), is a serious pest of wheat crop across the world. The present study was conducted to evaluate the potentials of the water plant extracts of Azadirachta indica (neem) or Eucalyptus camaldulensis and the entomopathogenic fungi (EPF); Beauveria bassiana or Metarhizium anisopliae against the aphid species. After 5 days of applications, the combined mixture of B. bassiana and eucalyptus extract caused the maximum mortality rate (87%). While the combination of B. bassiana with neem extract showed the least rate (54%). Fecundity was negatively affected by the single and combined treatments of EPF and botanicals extracts. The lowest fecundity (7 nymphs per female) was recorded when the aphid was treated by the binary mixture of B. bassiana and eucalyptus extract. Correspondent maximum fecundity (29 nymphs per female) in 5 days was recorded in control treatment, while 23 nymphs were produced by a single female when treated with the binary mixture of B. bassiana and neem extract. The results indicated that EPF and botanical extracts (neem or eucalyptus) caused significant reduction in survival and fecundity of S. avenae. Therefore, they may be used as promising natural alternatives to synthetic insecticides against the wheat aphid species.
36 citations
TL;DR: A high level of antibiosis in Darab2 compared with the other tested cultivars may decrease the population density of R. padi on wheat and also cause a suppression of cereal viruses and reduce the pesticide application to wheat fields of Iran.
Abstract: Taheri S., Razmjou J., Rastegari N. (2010): Fecundity and development rate of the bird cherry-oat aphid, Rhopalosiphum padi (L) (Hom.: Aphididae) on six wheat cultivars. Plant Protect Sci., 46: 72–78. Rhopalosiphum padi is a polyphagous species with a nearly worldwide distribution. Biological parameters of this aphid on six commonly grown wheat cultivars in the Fars province including Chamran, Darab2, Shiraz, Ghods, Marvdasht and Niknezhad were investigated at the two-leaf stage of wheat. The experiments were carried out at 24 ± 5°C, 65 ± 5% R.H. and a photoperiod of 14:10 h (L:D) in a greenhouse. The number of nymphs per female of R. padi was 62.05, 55.84, 49.89, 47.63, 42.76 and 40.65 (nymphs/female) on Niknezhad, Shiraz, Ghods, Marvdasht, Chamran, and Darab2, respectively. Also, the highest and the lowest rm values of this aphid were obtained on Niknezhad (0.381 per day) and Darab2 (0.328 per day), respectively. In addition, other population growth indices were estimated. In general, a high level of antibiosis in Darab2 compared with the other tested cultivars may decrease the population density of R. padi on wheat and also cause a suppression of cereal viruses (e.g. BYDV) and reduce the pesticide application to wheat fields of Iran.
34 citations
TL;DR: Findings suggest that M. persicae can develop a high level of resistance to sulfoxaflor, but fitness costs may result in a recovery of sensitivity when field populations are no longer exposed to sulf oxaflor.
Abstract: Sulfoxaflor is a newly released fourth-generation neonicotinoid insecticide for management of sap-feeding pests that have developed resistance to established insecticide groups. The risk of resistance developing to this pesticide in target pests is unclear. We selected a strain of the green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), for resistance to sulfoxaflor in the laboratory, which showed 199-fold resistance after 45 generations compared to the starting population. Life table analysis showed that the resistant strain had a fitness of 0.83 compared to the susceptible strain. Adult longevity of the resistant strain was reduced by 9.55% compared to the susceptible strain. The period when adults of the resistant strain produced offspring was reduced by 17.19%, while the mean fecundity of the resistant strain was reduced by 15%. These findings suggest that M. persicae can develop a high level of resistance to sulfoxaflor, but fitness costs may result in a recovery of sensitivity when field populations are no longer exposed to sulfoxaflor.
33 citations
TL;DR: Genome‐wide association mapping is effective for finding insect resistance loci and single nucleotide polymorphisms associated with soybean aphid resistance for multiple aphid biotypes are found.
Abstract: Soybean aphid [ Matsumura (Hemiptera: Aphididae)] is the most damaging insect pest of soybean [ (L.) Merr.] in the Upper Midwest of the United States and is primarily controlled by insecticides. Soybean aphid resistance (i.e., genes) has been documented in some soybean accessions but more sources of resistance are needed. Incorporation of the resistance into marketed varieties has also been slow. Genome-wide association mapping can aid in identifying resistant accessions by correlating phenotypic data with single nucleotide polymorphisms (SNPs) across a genome. Aphid population measures from 2366 soybean accessions were collected from published studies screening cultivated soybean () and wild soybean ( Siebold & Zucc.) with aphids exhibiting Biotype 1, 2, or 3 characteristics. Genotypic data were obtained from the SoySNP50K high-density genotyping array previously used to genotype the USDA Soybean Germplasm Collection. Significant associations between SNPs and soybean aphid counts were found on 18 of the 20 soybean chromosomes. Significant SNPs were found on chromosomes 7, 8, 13, and 16 with known genes. SNPs were also significant on chromosomes 1, 2, 4 to 6, 9 to 12, 14, and 17 to 20 where genes have not yet been mapped, suggesting that many genes remain to be discovered. These SNPs can be used to determine accessions that are likely to have novel aphid resistance traits of value for breeding programs.
28 citations
TL;DR: L Laboratory bioassays showed a superior insecticidal effect of the pyrethrin micro-emulsions compared to two commercial suspension concentrates of natural pyrethrins against the aphid.
Abstract: The insecticidal activity of a new nano-formulated natural pyrethrin was examined on the cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), and the predators Coccinella septempunctata L. (Coleoptera: Coccinellidae) and Macrolophus pygmaeus Rambur (Hemiptera: Miridae), in respect with the nano-scale potential to create more effective and environmentally responsible pesticides. Pyrethrin was nano-formulated in two water-in-oil micro-emulsions based on safe biocompatible materials, i.e., lemon oil terpenes as dispersant, polysorbates as stabilizers, and mixtures of water with glycerol as the dispersed aqueous phase. Laboratory bioassays showed a superior insecticidal effect of the pyrethrin micro-emulsions compared to two commercial suspension concentrates of natural pyrethrins against the aphid. The nano-formulated pyrethrins were harmless, in terms of caused mortality and survival time, to L3 larvae and four-instar nymphs of the predators C. septempunctata and M. pygmaeus, respectively. We expect that these results can contribute to the application of nano-technology in optimization of pesticide formulation, with further opportunities in the development of effective plant protection products compatible with integrated pest management practices.
27 citations
TL;DR: Parallel annual variation in the average maximum numbers of M. dirhodum, Sitobion avenae (Fabricius), and Rhopalosiphum padi (Linné) (Homoptera: Aphididae) indicated the following factors that affected their abundance: temperature in winter and host plant quality.
Abstract: In Central Europe, the most abundant aphid infesting the leaves of small grain cereals is Metopolophium dirhodum (Walker) (Homoptera: Aphididae). Annual variation in its seasonal dynamics was evaluated using a 25-yr series of standardized weekly censuses of winter wheat plots. M. dirhodum made up >50 % of the aphids on the foliage. Date of immigration (8 May–3 July), length of period of population increase (0–9 wk), and date of attaining maximum abundance (28 May–22 July) varied greatly. For the prediction, we regressed maximum numbers/tiller on numbers recorded in the first week after heading. The regression of maximum abundance on nonzero aphid counts revealed a critical number of ≥1.50 aphids/tiller, which if exceeded resulted in a harmful maximum abundance of ≥10 aphids/tiller at the peak. Zero aphid counts resulted in 10% of cases with a harmful maximum abundance. Using this regression for prediction will result in 18% of the recorded cases being false negatives and 9% false positives. Parallel annual variation in the average maximum numbers of M. dirhodum, Sitobion avenae (Fabricius) (Homoptera: Aphididae), and Rhopalosiphum padi (Linne) (Homoptera: Aphididae) indicated the following factors that affected their abundance: temperature in winter and host plant quality. The predictions apply only in areas where M. dirhodum is holocyclic and aphids do not overwinter in wheat stands.
TL;DR: Evaluation of combined pathogenicity of the fungal strains constitutes the novelty of this in-vitro study which revealed that both strains of B. bassiana are mutually compatible and can be utilized together as new biocontrol tools against destructive insect pests such as M. persicae.
Abstract: Green peach aphid, Myzus persicae (Hemiptera: Aphididae), is an economically important pest of crops within more than 40 plant families all over the world. This study encompasses in-vitro pathogenicity of two strains of Beauveria bassiana (BB-72 and BB-252) and one strain of Lecanicillium lecanii (V-4) against green peach aphid (M. persicae). Using a leaf-dip method, three different bioassays were conducted comprised of filtrates and conidial concentrations of BB-72, BB-252 and V-4 fungal strains and their binary combinations. Infiltrate bioassays, 2 mL fungal filtrate of each strain was used. In conidial bioassays, three different concentrations (i.e., 1 × 106, 1 × 107 and 1 × 108 conidia mL−1) of each fungal strain were used, while in binary combination bioassays, LC50 and LC33 of these fungal strains were evaluated. According to the results, maximum pathogenicity against test aphids was observed at 10th day of all treatments. Both strains of B. bassiana (BB-72 and BB-252) exhibited higher mortality of aphids (up to 95 and 91%, respectively) than L. lecanii (V-4) strain (87%) in all three types of bioassays. Moreover, binary combinations of BB-72 and BB-252 strains showed significantly higher aphid mortality (94%) than other combinations. Reduced mortality in case of fungal combinations of V-4 strain might be due to the antagonistic effect of L. lecanii strain along with both strains of B. bassiana. Nevertheless, evaluation of combined pathogenicity of the fungal strains constitutes the novelty of this in-vitro study which revealed that both strains of B. bassiana (i.e., BB-72 and BB-252) are mutually compatible and can be utilized together as new biocontrol tools against destructive insect pests such as M. persicae.
TL;DR: The empirical evidence for specialist insect adaptations toward milkweed toxins, coevolution between insects and milkweed plants, and canonical paradigms for sequestration are reviewed and the need to comprehensively study adaptations and specialization in divergent insect taxa is discussed.
Abstract: Studies of plant defenses and insect herbivores have been important in the development of our understanding of coevolution and specialization. Milkweed–herbivore systems have been a model for studying plant secondary chemistry defense evolution, insect adaptations to that chemistry, and coevolution between toxic plants and their herbivores for over a century. Yet, we are only beginning to unravel the multitude of adaptations required for insect specialization on milkweed plants. We review the empirical evidence for specialist insect adaptations toward milkweed toxins, coevolution between insects and milkweed plants, and canonical paradigms for sequestration and highlight the areas for further research. By comparing research performed with diverse milkweed insects, we discuss the need to comprehensively study adaptations and specialization in divergent insect taxa.
TL;DR: Two pollinator lines developed by the USDA-ARS in Lubbock, TX, exhibited tolerance as indicated by damage ratings and growth characteristics, such as plant height, number of leaves, and chlorophyll content, indicating a highly tolerant sorghum.
Abstract: The sugarcane aphid Melanaphis sacchari (Zehntner) was discovered infesting grain sorghum close to Beaumont, TX, near the Texas and Louisiana state line a few kilometers inland from the Gulf Coast in the late summer of 2013, and has been a perennial pest of grain, forage, and sweet sorghums. Our research was aimed at identifying sorghum germplasm that expresses host-plant resistance to the sugarcane aphid. We originally screened 36 lines including two known resistant sorghums (Tx2783 and DKS-37-07) and two known susceptible sources (WSH 117 and MORCH 858). From this screen, two pollinator lines (R.11143 and R.11259) developed by the USDA-ARS in Lubbock, TX, exhibited tolerance as indicated by damage ratings and growth characteristics, such as plant height, number of leaves, and chlorophyll content. Line R.11143 had a slight net gain in chlorophyll content in the infested plants compared to the noninfested plants, indicating a highly tolerant sorghum. The R.11143 and R.11259 lines also expressed s...
TL;DR: Aposymbiotic aphids, on both plant species, showed increased pathway activities, mechanical problems with the stylets, and delayed salivation in the phloem, confirming that B. aphidicola is involved in the plant–aphid interaction in relation to plant acceptance, presumably through a role in stylets penetration in the plants.
Abstract: The green peach aphid, Myzus persicae Sulzer (Hemiptera: Aphididae) is one of the potato important pests; it is the most efficient vector of potato viruses. Myzus persicae harbors the endosymbiotic bacteria Buchnera aphidicola which supplements their diet. There is increasing evidence that B. aphidicola is involved in plant-aphid interactions and we previously demonstrated that B. aphidicola disruption (aposymbiosis) affected the probing behavior of M. persicae on radish plants, delaying host plant acceptance. In this work, we evaluated the effect of aposymbiosis on the probing behavior of M. persicae on 2 Solanum species with different compatibility with M. persicae, Solanum tuberosum (susceptible) and Solanum stoloniferum (resistant) with the electrical penetration graph technique (EPG). To disrupt B. aphidicola, rifampicin was administered to aphids through artificial diets. Aposymbiotic aphids, on both plant species, showed increased pathway activities, mechanical problems with the stylets, and delayed salivation in the phloem. The extended time in derailed stylet mechanics affected the occurrence of most other probing activities; it delayed the time to the first phloem phase and prevented ingestion from the phloem. The effect of aposymbiosis was more evident in the compatible interaction of M. persicae-S. tuberosum, than in the incompatible interaction with S. stoloniferum, which generated the M. persicae-S. tuberosum interaction to become incompatible. These results confirm that B. aphidicola is involved in the plant-aphid interaction in relation to plant acceptance, presumably through a role in stylets penetration in the plant.
TL;DR: The results indicate that overall increases in urban land cover are not favourable for ladybirds as a group, and that fine scale habitat variables that are determined by garden owners have the potential to greatly affect the diversity of aphids and their primary predators.
Abstract: Urban gardens can harbour a high diversity of insects, which are critically important components of urban ecosystems. In this work, we investigate the richness and diversity of a major taxon of economic and ecological importance, the aphids (Homoptera: Aphididae), and their main insect predators, the hoverflies (Diptera: Syrphidae) and ladybirds (Coleoptera: Coccinellidae), in urban gardens. We examined how variation in environmental factors associated with urbanisation (garden host plant abundance, garden plant richness, garden size, proportion of impervious surfaces in the surrounding area) directly and indirectly (via prey and predator abundance) influence the local diversity and abundance of aphids, ladybirds, and hoverflies. Sixty-seven domestic gardens located in southern England were surveyed during the peak period of aphid abundance, and the numbers and identity of aphids and their predators were recorded. We observed 45 aphid species (179917 individuals in total), 15 hoverfly species (494 individuals) and 8 ladybird species (173 individuals). We found that aphid species richness and abundance were positively associated with utilised host plant abundance and garden plant species richness. Hoverfly abundance was positively correlated with garden plant richness. The abundance of ladybirds was positively correlated with aphid abundance and garden plant species richness, and negatively associated to the proportion of impervious surfaces in the surrounding environment. The difference in responses between the two major taxa of aphid predators may reflect differences in their behaviour and natural history. Our results indicate that overall increases in urban land cover are not favourable for ladybirds as a group, and that fine scale habitat variables that are determined by garden owners have the potential to greatly affect the general diversity of aphids and their main predators.
TL;DR: The results attained from population growth parameters indicated that both Chinese cabbage and bak choi were less suitable hosts for turnip aphids and should be considered as a possible source for developing resistance in breeding programs and integrated pest management strategies.
Abstract: Demographic parameters of the turnip aphid, Lipaphis erysimi (Kaltenbach) (Hemiptera: Aphididae), which is a serious pest of Brassica crops worldwide, were evaluated on five major Brassica vegetables (three varieties of Brassica oleraceae (Linnaeus) (Brassicaceae: Brassicales); kohlrabi, cabbage and ornamental cabbage, and two subspecies of Brassica rapa (Linnaeus) (Brassicaceae: Brassicales); Chinese cabbage and bak choi). The study was carried out under laboratory conditions at 25 ± 1°C, 70 ± 5% RH and 16:8 (L:D) h. Preadult developmental time, survival rate, female longevity, reproduction, and life table parameters were evaluated according to the age-stage specific life table method. The highest population growth parameters, i.e., net reproductive rate (R0), intrinsic rate of increase (r), and finite rate of increase (λ) were recorded on kohlrabi (R0 = 30.45 offspring, r = 0.2174 d-1, λ = 1.2429 d-1). These parameters were the lowest on Chinese cabbage (R0 = 13.00 offspring, r = 0.1503 d-1, and λ = 1.1621 d-1) and bak choi (R0 = 16.30 offspring, r = 0.1614 d-1, λ = 1.1752 d-1). The results attained from population growth parameters, together with population projection estimation based on the age-stage, two-sex life table theory, indicated that both Chinese cabbage and bak choi were less suitable hosts for turnip aphids and should be considered as a possible source for developing resistance in breeding programs and integrated pest management strategies.
TL;DR: The nutritional value of 14 honeydews excreted by 13 aphid species for the generalist aphid parasitoid Lysiphlebus testaceipes was evaluated and a positive correlation between the body sugar content of honeydew-fed parasitoids and their longevity was found.
TL;DR: Life table and predation data were collected for Coccinella septempunctata feeding on three different host aphid species, Aphis craccivora, Lipaphis erysimi, and Myzus persicae, under laboratory conditions, using age-stage, two-sex life table.
Abstract: Life table and predation data were collected for Coccinella septempunctata (Linnaeus) (Coleoptera: Coccinellidae) feeding on three different host aphid species, Aphis craccivora (Koch) (Hemiptera: Aphididae), Lipaphis erysimi (Kaltenbach) (Hemiptera: Aphididae), and Myzus persicae (Sulzer) (Hemiptera: Aphididae), under laboratory conditions, using age-stage, two-sex life table. The preadult developmental period of C. septempunctata was the shortest on M. persicae (21.12 d) and the longest on A. craccivora (28.81 d). Net reproductive rate (R₀) ranged from 77.31 offspring per individual on A. craccivora to 165.97 offspring per individual on M. persicae. Mean generation time (T) ranged from 39.10 d on M. persicae to 51.96 d on L. erysimi. Values of the intrinsic rate of increase (r) decreased in the order M. persicae, A. craccivora, and L. erysimi (0.1302, 0.0864 and 0.0848 dˉ¹, respectively). The highest finite rate of increase (λ) was observed on M. persicae (1.1391 dˉ¹) and the lowest was observed on A. craccivora and L. erysimi (1.0903 and 1.0885 dˉ¹, respectively). This information will be useful in relation to the mass rearing of C. septempunctata in biological control systems.
TL;DR: The notion that a well-timed foliar application can alleviated losses in yield in sorghum in the Texas Panhandle and potentially other regions of the High Plains is supported.
Abstract: In the High Plains, sugarcane aphid, Melanaphis sacchari Zehntner (Hemiptera: Aphididae), colonize grain sorghum, Sorghum bicolor (L) Moench (Cyperales: Poaceae), when it is in reproductive stages and aphid populations increase rapidly. Sugarcane aphid management recommendations based on aphid densities have been implemented in southern United States, but have not been assessed in the High Plains. Therefore, the goal of this work was to validate whether these guidelines can provide effective suppression of the aphids and improve yield. In a 2-y field experiment, sorghum susceptible (DKS44-20) and resistant (DKS37-07) to sugarcane aphids, with and without insecticide (clothianidin) seed treatments, was exposed to natural aphid infestations and treated with a foliar insecticide (flupyradifurone) once sugarcane aphid densities exceeded 50 per leaf. Further, to assess the effects of these tactics on sorghum yield, data were collected from plots that were not treated at the threshold. In both years, foliar insecticide applied at the density-based threshold decreased aphid numbers across sorghum hybrids with and without seed treatments and aphid densities remained below threshold for the remainder of the season. Yield of sorghum depended on sugarcane aphid pressure-when their densities were high (2016), the resistant hybrid with and without the foliar spray outperformed the unsprayed susceptible hybrid, while the susceptible hybrid had higher yields than resistant hybrid when sugarcane aphid pressure was low (2017). Outcomes of this work support the notion that a well-timed foliar application can alleviated losses in yield in sorghum in the Texas Panhandle and potentially other regions of the High Plains.
TL;DR: Two direct and indirect injury support tools can be parameterized with potential yields, market prices, and the costs of insecticide applications to guide treatment decisions to help manage pea aphid acting as both a direct pest and as a vector of the viruses in lentils in the Palouse region of northern Idaho and southeastern Washington State.
Abstract: The pea aphid, Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae), presents a dual threat to commercial pulse growers because it can inflict direct injury through feeding and indirect injury as a vector of two important viruses, Pea enation mosaic virus (PEMV) and Bean leafroll virus (BLRV). A decision support system is needed to help producers manage both of these threats in pulses. To address these gaps in lentil, Lens culinaris (Medikus) (Fabales: Fabaceae), we conducted field experiments near Moscow, Idaho in 2011 and 2012 with three objectives: 1) determine economic injury levels (EILs) for pea aphid in lentil based on the direct effects of their feeding on yield, 2) develop economic guidelines for treating aphids carrying PEMV or BLRV based on the impact on yield of virus inoculation at different times after crop emergence, and 3) provide a framework for using both of these decision tools as part of a comprehensive approach to pea aphid management in lentil. EILs were determined based on data from replicated field cage trials over 2 yr. Windows of economic vulnerability to viruses were determined based on artificial inoculation with viruses at different days after crop emergence over 2 yr. Both direct and indirect injury support tools can be parameterized with potential yields, market prices, and the costs of insecticide applications to guide treatment decisions. Together, the two tools comprise a decision support system for managing pea aphid acting as both a direct pest and as a vector of the viruses in lentils in the Palouse region of northern Idaho and southeastern Washington State.
TL;DR: An exclusion-cage experiment designed to isolate the impact of parasitoids from that of other resident natural enemies of the soybean aphid found that A. certus greatly outnumbered all other soy bean aphid Parasitoids, and that it significantly reduced aphid populations over a time span of less than two weeks compared to controls.
TL;DR: Two processes ensure a flexible production of asexual alate individuals, allowing aphids to adapt to changing environmental conditions, and these two processes are suggested to be a moderate level in response to aggregation, triggered by crowding cues and a high level inresponse to plant quality deterioration.
Abstract: Polyphenism constitutes a key example of the adaptability of a genotype to a shifting environment. In aphids, the relative production of apterous and alate individuals is influenced by cues resulting from increases in population density, changes in plant quality, and natural enemies. The ability to respond to multiple environmental cues offers aphids an effective way to optimize their fitness. Understanding the mechanisms behind alate morph production is particularly important in aphid species that are agricultural pests. We tested the effects of crowding and host plant quality cues on morph determination in Aphis glycines Matsumura (Hemiptera: Aphididae). We exposed A. glycines to pre‐natal and post‐natal crowding under laboratory conditions. In the field, we reared nymphs of A. glycines at high‐density vs. low‐density conditions in clip cages set on the top vs. bottom nodes of infested and uninfested soybean plants, Glycine max (L.) Merrill (Fabaceae). Apterous adult body size was used as an estimate of aphid performance, and the proportion of morphs developing under each condition was determined. Both pre‐ and post‐natal crowding induced the production of asexual alate individuals by A. glycines. In the field, we observed additive negative effects of lower overall plant quality (infested vs. uninfested plants), within‐plant differences in nutritional quality (bottom vs. top nodes), and high vs. low levels of crowding on aphid size. These three factors also interacted to increase the proportion A. glycines nymphs that developed wings. Our results suggest two levels in the production of asexual alate individuals by A. glycines: (1) a moderate level in response to aggregation, triggered by crowding cues, and (2) a high level in response to plant quality deterioration, triggered by both plant quality and crowding cues. These two processes ensure a flexible production of asexual alate individuals, allowing aphids to adapt to changing environmental conditions.
TL;DR: Jasmonate derivatives containing a hydroxy group, especially in correlation with a lactone ring, were more active than natural compounds and other derivatives studied.
Abstract: Jasmonates show great potential in sustainable agriculture due to their various roles in natural mechanisms of plant defense, and because they are non-toxic, non-mutagenic, and easily metabolized. The aim of the study was to explore structure–activity relationships of dihydrojasmone, cis-jasmone, and their derivatives at the plant–aphid interface. We focused on the behavioral responses of aphids, following the exogenous application of natural jasmonates and their derivatives to the host plants. Aphid probing behavior was examined using an electrical penetration graph technique (EPG). The chemoenzymatic transformation of cis-jasmone and the activity of two new derivatives are described. The application of cis-jasmone, dihydrojasmone, the hydroxyderivatives, epoxyderivatives, and alkyl-substituted δ-lactones hindered the foraging activity of Myzus persicae (Sulz.) (Hemiptera: Aphididae) during early stages of probing at the level of non-phloem tissues. The application of saturated bicyclic epoxy-δ-lactone enhanced plant acceptance by M. persicae. Jasmonate derivatives containing a hydroxy group, especially in correlation with a lactone ring, were more active than natural compounds and other derivatives studied. Jasmonates of the present study are worth considering as elements of sustainable aphid control as components of the “push–pull” strategy.
TL;DR: The predation rate and performance of Adalia bipunctata, Hippodamia variegata, and Scymnus interruptus Goeze fed on M. persicae infesting sweet pepper showed an immediate impact on the aphids and is more suitable for curative releases, however, it showed limited potential to establish in the crop.
Abstract: Myzus persicae (Sulzer) (Hemiptera: Aphididae) is one of the most common and harmful pest species attacking sweet pepper. Here, we compared the predation rate and performance of Adalia bipunctata (L.), Hippodamia variegata (Goeze), and Scymnus interruptus Goeze (Coleoptera: Coccinellidae) fed on M. persicae infesting sweet pepper. In the laboratory, when offered 150 aphids daily, A. bipunctata was the most voracious species (predation per adult female of 122.7 aphids per 24 h) followed by H. variegata (87.7) and S. interruptus (27.3). When offered 50 aphids, 92% of the S. interruptus larvae developed to adults, 48% of H. variegata, and only 7% of A. bipunctata. In greenhouse experiments, A. bipunctata completely eradicated the aphid population within 2 days following release, whereas H. variegata and S. interruptus initially reduced the aphid population; however, in the long‐term, the infestation was not controlled. Adults of A. bipunctata remained on the plants even in the absence of prey but they laid almost no eggs. Very few adults of H. variegata and S. interruptus were recorded on the plants despite the presence of prey, yet egg laying was observed. Overall, A. bipunctata had an immediate impact on the aphids and is more suitable for curative releases. However, it showed limited potential to establish in the crop. Due to their capacity to complete development with low prey availability, the potential of H. variegata and S. interruptus for preventative releases against aphids in greenhouse crops should be studied further.
TL;DR: The results presented in this study revealed that there was no relation between high alkaline protease activities and high virulence isolates.
Abstract: The aim of the present study is to investigate the effect of three entomopathogenic fungi (EPF) (Beauveria bassiana, Cladosporium cladosporioides, and Verticillium alfalfae) on the aphid species, Metopolophium dirhodum (Walker) (Hemiptera: Aphididae). The selected EPF were isolated from the agricultural soil of the National Institute of Plant Protection (INPV) in Constantine, Algeria, and were tested against the aphid insects that were collected from the same area. The aphid species M. dirhodum were exposed to each fungal spore suspensions 107 conidia/ml for 10 s. Percent mortality was recorded at 1, 3, 5, and 7 days post treatment. Percentage mortalities, 7 days post treatment, were 95.83, 63.98, and 51.83% by B. bassiana, C. cladosporioides, and V. alfalfae, respectively. The higher protease activities were observed for isolate V. alfalfae with 95 U/ml, followed by B. bassiana with 38.26 U/ml, and finally C. cladosporioides with 35, 65 U/ml. The results presented in this study revealed that there was no relation between high alkaline protease activities and high virulence isolates.
TL;DR: The use of reclaimed wastewater for crop irrigation would not affect aphid populations, but could hinder or delay crop production, as well as reduce growth reduction in antibiotic and mixture treatments, specifically in wet root masses.
Abstract: Many countries are utilizing reclaimed wastewater for agriculture as water demands due to drought, rising temperatures, and expanding human populations. Unfortunately, wastewater often contains biologically active, pseudopersistant pharmaceuticals, even after treatment. Runoff from agriculture and effluent from wastewater treatment plants also contribute high concentrations of pharmaceuticals to the environment. This study assessed the effects of common pharmaceuticals on an agricultural pest, the aphid Myzus persicae (Sulzer, Hemiptera: Aphididae). Second instar nymphs were transferred to bell peppers (Capsicum annuum) that were grown hydroponically. Treatment plants were spiked with contaminants of emerging concern (CECs) at environmentally relevant concentrations found in reclaimed wastewater. M. persicae displayed no differences in population growth or microbial community differences due to chemical treatments. Plants, however, displayed significant growth reduction in antibiotic and mixture treatments, specifically in wet root masses. Antibiotic treatment masses were significantly reduced in the total and root wet masses. Mixture treatments displayed an overall reduction in plant root wet mass. Our results suggest that the use of reclaimed wastewater for crop irrigation would not affect aphid populations, but could hinder or delay crop production.
TL;DR: The cabbage cultivar Yuanbao was resistant to M. persicae and could be used in the development of integrated pest management (IPM) programs against the aphid in the field.
Abstract: The green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), is an important pest of many crops in the world and a vector of more than 100 plant viruses. It is a major pest of Brassica vegetables such as Chinese cabbage in northern China. Chemical control is extensively used to manage this aphid around the world; however, development of insecticide resistance has been a major obstacle facing growers. Host plant resistance in Chinese cabbage against M. persicae has not been reported yet. In this study, we investigated the resistance categories in seven Chinese cabbage cultivars against M. persicae. The resistance categories of these cultivars included antixenosis, antibiosis, and tolerance related to leaf color and wax content. The cultivar 'Yuanbao' had antibiotic and tolerance effects on the aphid. The rate of intrinsic increase (rm) of M. persicae was lower on Yuanbao compared with the other six cultivars. Yuanbao also had the highest antibiosis against the aphid. The aphid preferred 'Qingan 80', which had the highest wavelength (green) in leaf color. The highest wax content was found in Yuanbao, which had a significantly negative correlation with the preference of M. persicae. The cabbage cultivar Yuanbao was resistant to M. persicae and could be used in the development of integrated pest management (IPM) programs against the aphid in the field.
TL;DR: Important data is provided that contribute to the understanding of how soybean aphids (biotype 1) feed on soybean genotypes with various aphid resistant genes and categories and is useful in soybean breeding programs focusing on developing genotype with greater resistance to insects.
Abstract: Aphis glycines Matsumura (Hemiptera: Aphididae) is a serious pest of soybean in North America. Plant resistance is a valuable tool for the management of this pest, and a better understanding of the interactions between aphid and soybeans expressing varying levels and different categories of resistance can assist in the development of aphid resistant or tolerant genotypes. The electrical penetration graph (EPG) technique was used to evaluate the feeding behavior of A. glycines (biotype 1) on 4 soybean genotypes: (1) ‘Dowling’ (contains Rag1 gene and exhibits antibiosis); (2) PI 200538 (contains Rag2 gene and exhibits antixenosis); (3) KS4202 (exhibits tolerance); and (4) ‘SD76RR’ (susceptible to aphid). Aphids spent shorter periods in the sieve element phase on ‘Dowling’ and exhibited a greater number of pathway phases, non-probing events, and a longer time in nonprobing events in PI 200538 and ‘Dowling.’ For ‘SD76RR’ and KS4202, aphids demonstrated more sustained phloem ingestion, spent shorter time in non-probing events, and exhibited fewer pathway phases and potential drops. These results indicate that resistance factors are present in the phloem of ‘Dowling.’ For PI 200538, it is suggested that antixenotic factors are involved in resistance to A. glycines. Because KS4202 is tolerant to biotype 1 of A. glycines, the suitability of this genotype was expected already. This study provides important data that contribute to the understanding of how soybean aphids (biotype 1) feed on soybean genotypes with various aphid resistant genes and categories. In addition to assisting in the distinction between resistance categories, these results are useful in soybean breeding programs focusing on developing genotypes with greater resistance to insects.
TL;DR: In this article, the effects of mineral oil on potato pests were investigated, including potato aphids, Macrosiphum euphorbiae (Thomas) (Hemiptera: Aphididae), green peach aphids and Colorado potato beetles.
Abstract: Mineral oil is a product used to reduce Potato Virus Y transmission in potato fields. However, there is little information available about other effects that oil may have on insect pests of potato. To better understand how mineral oil affects potato pests, we performed a series of experiments testing the effects of oil on mortality, behavior, and development of potato aphids, Macrosiphum euphorbiae (Thomas) (Hemiptera: Aphididae), green peach aphids, Myzus persicae (Sulzer) (Hemiptera: Aphididae), and Colorado potato beetles, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae). All three species showed negative behavioral responses to oil-treated potato foliage. Oil treatment also increased aphid mortality. Colorado potato beetle mortality was not affected, but developing on oil-treated potato plants resulted in prolonged development and smaller adults. Additionally, oil acted synergistically with the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Clavicipitaceae); Colorado potato beetle larvae were killed more rapidly when sprayed with both products compared with when sprayed with B. bassiana alone. Based on these results, mineral oil has the potential for expanded use in potato IPM programs.