Aphid Species Research Articles

Greenbug feeding-induced resistance to sugarcane aphids in sorghum

Plants are attacked by multiple insect pest species and insect herbivory can alter plant defense mechanisms. The plant defense responses to a specific herbivore may also contribute to the herbivore growth/survival on plants. Feeding by one insect species can modulate the plant defenses, which can either facilitate or hamper the colonization of subsequent incoming insects. However, little is known about the effect of sequential herbivory on sorghum plants. In this study, we demonstrate that a specialist aphid, sugarcane aphid (SCA; Melanaphis sacchari) grows faster on sorghum than a generalist aphid species, greenbug (GB; Schizaphis graminum). We also determined how the pre-infestation of SCA on sorghum affected the invasion of GB and vice-versa. Our sequential herbivory experiments revealed that SCA reproduction was lower on GB-primed sorghum plants, however, the reverse was not true. To assess the differences in plant defenses induced by specialist vs. generalist aphids, we monitored the expression of salicylic acid (SA) and jasmonic acid (JA) marker genes, and flavonoid biosynthetic pathway genes after 48 h of aphid infestation. The results indicated that GB infestation induced higher expression of SA and JA-related genes, and flavonoid pathway genes (DFR, FNR, and FNSII) compared to SCA infestation. Overall, our results suggested that GB-infested plants activate the plant defenses via phytohormones and flavonoids at early time points and hampers the colonization of incoming SCA, as well as explain the reproductive success of SCA compared to GB.

Population dynamics of migrant wheat aphids in China's main wheat production region and their interactions with bacterial symbionts.

Sitobion miscanthi, Rhopalosiphum padi, and Schizaphis graminum are the three main pests in Chinese wheat-producing regions. In 2020, they are classified into the Chinese Class I list of agricultural diseases and pests, due to their severe harm to wheat plantings. S. miscanthi, R. padi, and S. graminum are migrant pests, and understanding their migration patterns and simulating their migration trajectories would improve forecasting and controlling them. Furthermore, the bacterial community of the migrant wheat aphid is also less known. In this study, we employed a suction trap to uncover the migration patterns of the three wheat aphid species in Yuanyang county, Henan province, during 2018 to 2020. And then the migration trajectories of S. miscanthi and R. padi were simulated using the NOAA HYSPLIT model. The interactions between wheat aphids and bacteria were further revealed by specific PCR and 16S rRNA amplicon sequencing. The results showed that the population dynamics of migrant wheat aphids was varied. Most of the trapped samples were identified to be R. padi, and S. graminum was the least collected sample. Typically, R. padi had two migration peaks in the 3 years, whereas S. miscanthi and S. graminum only exhibited one migration peak in 2018 and 2019. Moreover, the aphid migration trajectories varied over the years. Generally, the aphids originated from the south and migrated to the north. Herein, the infections of three main aphid facultative bacterial symbionts, Serratia symbiotica, Hamiltonella defensa, and Regiella insercticola, were detected in S. miscanthi and R. padi with specific PCR. Rickettsiella, Arsenophonus, Rickettsia, and Wolbachia were further identified with 16S rRNA amplicon sequencing. Biomarker searching indicated that Arsenophonus was significantly enriched in R. padi. Furthermore, diversity analyses showed that the bacterial community of R. padi had a higher richness and evenness than that of S. miscanthi. In conclusion, this study expands our knowledge about the migration patterns of aphids in the main wheat plant region of China and reveals the interactions between bacterial symbionts and migrant aphids.

Detection of cassava brown streak ipomoviruses in aphids collected from cassava plants

Cassava is an important staple food in Africa and a major source of carbohydrates for 800 million people globally. However, cassava suffers severe yield losses caused by many factors including pests and diseases. A devastating disease of cassava is cassava brown streak disease (CBSD) caused by the cassava brown streak ipomoviruses (CBSIs) (family Potyviridae), Cassava brown streak virus (CBSV), and Ugandan cassava brown streak virus (UCBSV). Spread of CBSD is mainly through planting infected stem cuttings used for propagation. Transmission of CBSIs by the insect vector (Bemisia tabaci) has been reported. However, experimental transmission efficiencies of CBSIs are usually low. Recent research has showed the occurrence of a DAG motif associated with aphid transmission in other potyviruses, within the coat protein gene of CBSV. Consequently this study aimed to explore the possibility that besides whiteflies, aphids may transmit CBSIs. Cassava plants were assessed during a survey for occurrence of CBSD and aphids as potential alternative CBSIs vectors. We collected aphids from CBSD-symptomatic and symptomless cassava plants within farmers' fields in Uganda during April–July 2020. The aphids were analyzed for the presence of CBSIs by reverse transcriptase-polymerase chain reaction (RT-PCR) and to determine aphid species using mitochondrial cytochrome oxidase (mtCOI) barcoding. Unusual aphid infestation of cassava plants was observed at 35 locations in nine districts across Uganda and on 11 other plant species within or adjacent to cassava fields. This is the first report of aphids infesting cassava in Uganda. Molecular analysis of the aphid confirmed presence of three different aphid species in the surveyed cassava fields, namely, Aphis solanella, Aphis fabae mordvilkoi, and Rhopalosiphum sp. mtCOI nucleotide sequences for the aphids in which CBSIs were detected are deposited with Genbank under accession numbers OP223337-40. Both UCBSV and CBSV were detected by RT-PCR in aphids collected from cassava fields with CBSD-affected plants. The CBSIs were detected in 14 aphid samples collected from 19 CBSD-symptomatic cassava plants. These results suggest the ability of aphids to acquire CBSIs, but transmission experiments are required on their vector potential.

Bacterial volatiles elicit differential olfactory responses in insect species from the same and different trophic levels.

Insect communities consist of species from several trophic levels that have to forage for suitable resources among and within larger patches of nonresources. To locate their resources, insects use diverse stimuli, including olfactory, visual, acoustic, tactile and gustatory cues. While most research has focused on cues derived from plants and other insects, there is mounting evidence that insects also respond to volatile organic compounds (VOCs) emitted by microorganisms. However, to date little is known about how the olfactory response of insects within and across different trophic levels is affected by bacterial VOCs. In this study, we used Y-tube bioassays and chemical analysis of VOCs to assess how VOCs emitted by bacteria affect the olfactory response of insects of the same and different trophic levels. Experiments were performed using two aphid species (Amphorophora idaei Börner and Myzus persicae var. nicotianae Blackman), three primary parasitoid species (Aphidius colemani Viereck, A. ervi Haliday, and A. matricariae Viereck), and two hyperparasitoid species (Asaphes suspensus Nees and Dendrocerus aphidum Rondani). Olfactory responses were evaluated for three bacterial strains (Bacillus pumilus ST18.16/133, Curtobacterium sp. ST18.16/085, and Staphylococcus saprophyticus ST18.16/160) that were isolated from the habitat of the insects. Results revealed that insects from all trophic levels responded to bacterial volatiles, but olfactory responses varied between and within trophic levels. All bacteria produced the same set of volatile compounds, but often in different relative concentrations. For 11 of these volatiles we found contrasting correlations between their concentration and the behavior of the primary parasitoids and hyperparasitoids. Furthermore, olfactometer experiments on three of these compounds confirmed the contrasting olfactory responses of primary parasitoids and hyperparasitoids. The potential of these findings for the development of novel semiochemical-based strategies to improve biological aphid control has been discussed.

PM 7/31 (2) Citrus tristeza virus

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Non-destructive insect metabarcoding as a surveillance tool for the Australian grains industry: a first trial for the iMapPESTS smart trap

Surveillance and long-term monitoring of insect pest populations are of paramount importance to limit dispersal and inform pest management. Molecular methods have been employed in diagnostics, surveillance and monitoring for the past few decades, often paired with more traditional techniques relying on morphological examinations. Within this context, the ‘iMapPESTS: Sentinel Surveillance for Agriculture’ project was conceptualised to enhance on-farm pest management decision-making via development and deployment of smart traps, able to collect insects, as well as recording associated environmental data. Here, we compared an iMapPESTS ‘Sentinel’ smart trap to an alternative suction trap over a 10-week period. We used a non-destructive insect metabarcoding approach complemented by insect morphological diagnostics to assess and compare aphid species presence and diversity across trap samples and time. Furthermore, we paired this with environmental data recorded throughout the sampling period. This methodology recorded a total of 497 different taxa from 70 traps over a 10-week period in the grain-growing region in western Victoria. This included not only the 14 aphid target species, but an additional 12 aphid species, including a new record for Victoria. Ultimately, with more than 450 bycatch species detected, this highlighted the value of insect metabarcoding, not only for pest surveillance, but also at a broader ecosystem level, with potential applications in integrated pest management and biocontrol.

P450-mediated resistance in Myzus persicae (Sulzer) (Hemiptera: Aphididae) reduces the efficacy of neonicotinoid seed treatments in Brassica napus.

The prophylactic use of seeds treated with neonicotinoid insecticides remains an important means of controlling aphid pests in canola (Brassica napus) crops in many countries. Yet, one of the most economically important aphid species worldwide, the peach potato aphid (Myzus persicae), has evolved mechanisms which confer resistance to neonicotinoids, including amplification of the cytochrome P450 gene, CYP6CY3. While CYP6CY3 amplification has been associated with low-level resistance to several neonicotinoids in laboratory acute toxicity bioassays, its impact on insecticide efficacy in the field remains unresolved. In this study, we investigated the impact of CYP6CY3 amplification on the ability of M. persicae to survive neonicotinoid exposure under laboratory and semi-field conditions. Three M. persicae clones, possessing different copy numbers of CYP6CY3, were shown to respond differently when exposed to the neonicotinoids, imidacloprid and thiamethoxam, in laboratory bioassays. Two clones, EastNaernup209 and Osborne171, displayed low levels of resistance (3-20-fold), which is consistent with previous studies. However, in a large-scale semi-field trial, both clones showed a surprising ability to survive and reproduce on B. napus seedlings grown from commercial rates of neonicotinoid-treated seed. In contrast, an insecticide-susceptible clone, of wild-type CYP6CY3 copy number, was unable to survive on seedlings treated in the same manner. Our findings suggest that amplification of CYP6CY3 in M. persicae clones substantially impairs the efficacy of neonicotinoid seed treatments when applied to B.napus. These findings highlight the potentially important real-world implications of resistances typically considered to be 'low level' as defined through laboratory bioassays. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Diversity of endosymbiotic bacteria in the pea aphid (Acyrthosiphon pisum) on alfalfa in Chile

Facultative bacterial endosymbionts are prevalent in aphid pest species and key organisms for the rapid adaptation to changing environment conditions under agricultural management. Facultative endosymbiont interactions allow beneficial phenotypes of insect hosts, providing resistance against natural enemies, fungal infections as well as enhanced resistance to thermal conditions, among others. These interactions have been highlighted as important modulators in the evolution of aphid defenses, being a key aspect for the invasive potential of aphids as pests. In this study, we have examined the bacterial community diversity associated to the pea aphid Acyrthosiphon pisum on alfalfa (Medicago sativa L.) crops in Central Chile by determining the presence and abundance of the seven most common facultative endosymbionts reported for aphid species, including: Hamiltonella defensa, Regiella insecticola, Serratia symbiotica, Spiroplasma sp., Rickettsia sp., Rickettsiella viridis and Fukatsuia symbiotica (or pea aphid X-type symbiont’ PAXS), using a PCR-based approach across species-specific primers, in 16 alfalfa fields during the Chilean spring in the Maule Region. We reported six of the seven endosymbiont species studied, observing a high frequency of infected aphids being the endosymbiont H. defensa, the most predominant among the aphid populations in the different alfalfa fields studied. As H. defensa has been extensively studied in its defensive role to parasitoids, we discuss implications for biological control of this aphid pests. We also discuss the absence of a relevant defensive endosymbiont such as F. symbiotica in the Chilean pea aphid populations and potential implications for the success of the pea aphid biological control program.

The Known and Unknowns of Aphid Biotypes, and Their Role in Mediating Host Plant Defenses

Insect species are subjected to disparate selection pressure due to various biotic and abiotic stresses. Management practices including the heavy use of chemical insecticides and introduction of insect-resistant plant cultivars have been found to accelerate these processes. Clearly, natural selection coupled with human intervention have led to insect adaptations that alter phenotypes and genetic structure over time, producing distinct individuals with specialized traits, within the populations, commonly defined as biotypes. Biotypes are commonly found to have better fitness in the new environment and, in the case of aphids, the most commonly studied system for biotypes, have the ability to successfully infest previously resistant host plants and new species of host plants. Although a large number of studies have explored biotypes, the concept for defining biotypes varies among scientists, as we lack a consistency in estimating biotype behavior and their variation within and between biotypes. The concept of biotypes is even more complicated in aphid species (Aphidoidea), as they undergo parthenogenetic reproduction, making it difficult to understand the source of variation or quantify gene flow. In this review, we aim to illuminate the concept of biotype and how it has been used in the study of aphids. We intend to further elaborate and document the existence of aphid biotypes using sugarcane aphid (Melanaphis sacchari) as a model to understand their differences, level of variation, evolution, and significance in pest management.

Development of Reverse Transcription Recombinase Polymerase Amplification (RT-RPA): A Methodology for Quick Diagnosis of Potato Leafroll Viral Disease in Potato.

Potatoes are developed vegetatively from tubers, and therefore potato virus transmission is always a possibility. The potato leafroll virus (PLRV) is a highly devastating virus of the genus Polerovirus and family Luteoviridae and is regarded as the second-most destructive virus after Potato virus Y. Multiple species of aphids are responsible for the persistent and non-propagating transmission of PLRV. Due to intrinsic tuber damage (net necrosis), the yield and quality are drastically diminished. PLRV is mostly found in phloem cells and in extremely low amounts. Therefore, we have attempted to detect PLRV in both potato tuber and leaves using a highly sensitive, reliable and cheap method of one-step reverse transcription-recombinase polymerase amplification (RT-RPA). In this study, an isothermal amplification and detection approach was used for efficient results. Out of the three tested primer sets, one efficiently amplified a 153-bp product based on the coat protein gene. In the present study, there was no cross-reactivity with other potato viruses and the optimal amplification reaction time was thirty minutes. The products of RT-RPA were amplified at a temperature between 38 and 42 °C using a simple heating block/water bath. The present developed protocol of one-step RT-RPA was reported to be highly sensitive for both leaves and tuber tissues equally in comparison to the conventional reverse transcription-polymerase chain reaction (RT-PCR) method. By using template RNA extracted employing a cellular disc paper-based extraction procedure, the method was not only simplified but it detected the virus as effectively as purified total RNA. The simplified one-step RT-RPA test was proven to be successful by detecting PLRV in 129 samples of various potato cultivars (each consisting of leaves and tubers). According to our knowledge, this is the first report of a one-step RT-RPA performed using simple RNA extracted from cellular disc paper that is equally sensitive and specific for detecting PLRV in potatoes. In terms of versatility, durability and the freedom of a highly purified RNA template, the one-step RT-RPA assay exceeds the RT-PCR assay, making it an effective alternative for the certification of planting materials, breeding for virus resistance and disease monitoring.

Intraguild Predation of Hippodamia variegata on Aphid Mummies in Cotton Field.

Intraguild predation among arthropod predators in agricultural ecosystems may have a negative impact on biological control. At present, there are few direct reports on trophic relationships among participants of predation in field groups. In this study, we measured the feeding choices of Hippodamia variegata (Goeze) towards mummies with different densities of Aphis gossypii Glover. The dynamics of the occurrence of mummies in the cotton field were investigated over 2017-2019. Singleplex PCR and multiplex PCR were used to detect the predation of 2090 H. variegata individuals on aphids and mummies in Xinjiang cotton field, which revealed the intraguild predation frequency between H. variegata and various parasitoids. There was no obvious feeding preference of H. variegata towards live aphids or mummies, which mainly depended on the relative density of prey. Among the four species of aphids detected in H. variegata, A. gossypii had a high detection rate and was the main prey source of the ladybeetle in the cotton filed. Mostly, ladybeetles consumed parasitoids through mummies, with 6.39% directly feeding on adult parasitoids. H. variegata had strong trophic links to both parasitoids and aphids. We established a food web of aphids-primary parasitoids-hyperparasitoids-H. variegata, which can be used to evaluate the pest control ability of H. variegata from a new perspective.

Dynamic changes in species richness and community diversity of symbiotic bacteria in five reproductive morphs of cotton aphid Aphis gossypii Glover (Hemiptera: Aphididae).

Reproductive polymorphism and symbiotic bacteria are commonly observed in aphids, but their interaction remains largely unclear. In polymorphic aphid species (Aphis gossypii), offspring of parthenogenetic females (PFs) develops into sexuparae which produces gynoparae and males successively. Gynoparae further produces sexual females (SFs), and these sexual females mate with males to produce offspring. In this study, we investigated the dynamic changes of symbiotic bacteria during the above-mentioned five reproductive morph switch in A. gossypii via 16S rRNA sequencing technology. The results showed that species richness and community diversity of symbiotic bacteria in males were the highest. Proteobacteria was absolutely dominant bacterial phylum (with relative abundance of more than 90%) in the five reproductive morphs of A. gossypii, and Buchnera was absolutely dominant genus (with relative abundance of >90%), followed by Rhodococcus, Pseudomonas, and Pantoea. Male-killing symbiont Arsenophonus presented the highest relative abundance in gynoparae, a specific morph whose offsprings were exclusively sexual females. Both principal component analysis (PCA) and clustering analysis showed trans-generation similarity in microbial community structure between sexuparae and sexual females, between PFs and gynoparae. PICRUSt 2 analysis showed that symbiotic bacteria in the five reproductive morphs were mainly enriched in metabolic pathways. Reproductive morph switch induced by environmental changes might be associated with bacterial community variation and sexual polymorphism of aphids. This study provides a new perspective for further deciphering the interactions between microbes and reproductive polymorphism in host aphids.

Transcriptomic and proteomic analyses provide insights into host adaptation of a bamboo-feeding aphid.

Salivary glands and their secreted proteins play an important role in the feeding process of sap-sucking aphids. The determination of saliva composition is an important step in understanding host plant adaptation of aphids. Pseudoregma bambucicola is a severe bamboo pest in subtropical areas and the only aphid species that can exclusively feed on hard stalks of bamboos. How this species can penetrate and degrade hard bamboo cell walls and utilize a very specialized niche are important unanswered questions. In this study, comprehensive analyses based on transcriptome sequencing, RT-qPCR, liquid chromatography-tandem spectrometry (LC-MS/MS) and bioinformatics were conducted on dissected salivary glands and secreted saliva of P. bambucicola to characterize the overall gene expression and salivary protein composition, and to identify putative effector proteins important for aphid-plant interactions. Some secretory proteins homologous to known aphid effectors important for aphid-plant interactions, such as digestive enzymes, detoxifying and antioxidant enzymes and some effectors modulating plant defenses, are also detected in salivary gland transcriptome and salivary gland and/or saliva secretomes in P. bambucicola. This indicates that these effectors are probably be essential for enabling P. bambucicola feeding on bamboo host. Although several plant cell wall degrading enzymes (PCWDEs) can be identified from transcriptome, most of the enzymes identified in salivary glands showed low expression levels and they only represent a small fraction of the complete set of enzymes for degrading cellulose and hemicellulose. In addition, our data show that P. bambucicola has no its own ability to produce pectinases. Overall, our analyses indicate that P. bambucicola may lose its own ability to express and secrete key PCWDEs, and its adaptation to unique feeding habit may depend on its symbiotic bacteria.

Analysis of the Genetic Diversity of Two Rhopalosiphum Species from China and Europe Based on Nuclear and Mitochondrial Genes.

Population genetic studies can reveal clues about the evolution of adaptive strategies of aphid species in agroecosystems and demonstrate the influence of environmental factors on the genetic diversity and gene flow among aphid populations. To investigate the genetic diversity of two Rhopalosiphum aphid species from different geographical regions, 32 populations (n = 535) of the bird cherry-oat aphid (Rhopalosiphum padi Linnaeus) and 38 populations (n = 808) of the corn leaf aphid (Rhopalosiphum maidis Fitch) from China and Europe were analyzed using one nuclear (elongation factor-1 alpha) and two mitochondrial (cytochrome oxidase I and II) genes. Based on the COI-COII sequencing, two obvious clades between Chinese and European populations and a low level of gene flow (Nm = 0.15) were detected in R. padi, while no geographical-associated genetic variation was found for EF-1α in this species. All genes in R. maidis had low genetic variation, indicating a high level of gene flow (Nm = 5.31 of COI-COII and Nm = 2.89 of EF-1α). Based on the mitochondrial result of R. padi, we concluded that the long distance between China and Europe may be interrupting the gene flow. The discordant results of nuclear gene analyses in R. padi may be due to the slower evolution of nuclear genes compared to mitochondrial genes. The gene exchange may occur gradually with the potential for continuous migration of the aphid. This study facilitates the design of control strategies for these pests.

Life Cycle and Feeding Efficacy of Micromus Igortus (Bank) Brown Lacewing Against Myzus Persicae (Sulzer)

Myzus persicae(Sulzer) (Hemiptera : aphididae) is most polyphagous and economically important pest.Managment of M.persicae by using insecticide and pesticide is difficult as they resides under leaves and curls. Natural enemies play important role in controlling pest population. M.persicae have wide range of predators such as coccinellid beetle, lacewings, syrphid flies, spiders and aphid midges. Some hymenopteran parasitoids significantly lower population such aof Aphidius matricariae (Haliday Braconidae) and Aphelinus asychis Walker (Aphelinidae) and Diatellaria rapae. Micromus igortus Bank (Brown lacewing) has average predator potential against M. persicae than other aphid species. Micromus igortus mostly feed on Aphis craccivora and followed by Aphis gossypi. Biology and feeding efficacy of brown lacewing were studied in the fields from Kolhapur district, Maharashtra under laboratory condition in Shivaji University, Kolhapur. All stages of Brown lacewing and adults also have significant predatory potential against M.persicae. Feeding potential increases as the instars progressed their development. Rate of consumption on stage of 1st ,2nd, and 3rd instar of lacewing were average 11.15 days (Range Minimum 6.8 – Range maximum 15.5 days), 39.135 days (Range min. 23.5 – max. 31.27 days), 52.48 days (Range min. 46.91- max. 58.04 days ) respectively per day. Third instar is proved to be most prodigious feeder as they feed on large number of aphids. Lifecycle period for egg incubation, larval development, prepupal, pupal and adult period,total lifespan were 4.36 days(Range min. 4- max.5 days), 6.2 days (5-7 days), 1.3 days (1-2 days), 6.1 days (5-7days),9.6 days(8-12 days),29.32 days (28-32 days) respectively. The above studies will help to know the lifecycle of Lacewing in field conditions and proves the predatory potential of brown lacewing.

Efficacy of Imidacloprid Seed Treatments against Four Wheat Aphids under Laboratory and Field Conditions

Imidacloprid seed treatments are effective at reducing the cohorts of many insect pests on crops such as cotton, corn, and cereals. The effects of imidacloprid seed treatments depend on the aphid species. In China, there are four wheat aphid species-Sitobion avenae (Fabricius), Rhopalosiphum padi (Linnaeus), Schizaphis graminum (Rondani), and Metopolophium dirhodum (Walker)-and for a given region, these four aphid species differ in dominance with changes in cultivation practices and climate. Therefore, it is necessary to evaluate the effects of imidacloprid seed treatments on the four different aphid species. In experiments in the laboratory, imidacloprid seed treatments significantly reduced the survival rates of S. avenae, R. padi, and S. graminum to 57.33 ± 2.86%, 12.67 ± 1.92%, and 20.66 ± 2.33%, respectively, but for M. dirhodum, there was no significant difference between the control (96.33 ± 1.08%) and the treatment (97.00 ± 0.98%). The fecundities of the four aphid species were much reduced, especially for R. padi when feeding on treated wheat plants. For the field survey, only three aphid species were considered because the density of S. graminum was too low to be analyzed. The effects of imidacloprid seed treatment on the three aphid species in the field were consistent with the laboratory results. Imidacloprid seed treatment reduced the population sizes of S. avenae and R. padi at rates of 70.30 ± 3.15% and 87.62 ± 2.28%, respectively, for the whole wheat season in the field. For M. dirhodum, imidacloprid seed treatments were less effective, and the densities of M. dirhodum increased on four sample days. From this study, we confirmed that the effect of imidacloprid seed treatment varied with the composition of aphid species, being especially less effective for M. dirhodum.

ASSOCIATION OF APHIDS (HOMOPTERA: APHIDIDAE) WITH THE FLOWERING PLANTS OF NITROGEN-FIXING CLADE OF FABIDS (ANGIOSPERMS: EUDICOTS) IN INDIA

The present checklist deals with the association of aphids with the plants belonging to the four orders of nitrogen-fixing clade of fabids eudicot angiosperms, i.e. Cucurbitales, Fabales, Fagales and Rosales recorded in India. Total 294 species of plants of these orders belonging to 124 genera and 13 families are associated with 239 species of aphids put into 102 genera and 7 subfamilies of aphids. The aphids are related with only two families of Cucurbitales, Begoniaceae and Cucurbitaceae. Single species of Begoniaceae and 21 species of Cucurbitaceae are associated with 2 and 25 species of aphids, respectively. Almost 67 species of aphids are associated with 111 species of plants belonging to Fabaceae. Fagales includes 3 families, Betulaceae, Fagaceae and Juglandaceae and 38, 89 and 20 species of aphid use 6, 16 and 3 species of plants of these families, respectively. Among Rosales, maximum species of plants (89 species) of Rosaceae are infested by 166 species of aphids followed by Moraceae (17 species of plants by 27 species of aphids), Urticaceae (13 species of plants by 28 species of aphids), Cannabaceae (6 species of plants by 7 species of aphids), and less than it on Rhamnaceae, Ulmaceae and Elaeagnaceae. Aphis (Aphis) gossypii Glover is highly polyphagous on this clade of eudicots infesting 73 plant species, followed by Aphis (Aphis) spiraecola Patch (36 plant species), Myzus (Nectarosiphon) persicae (Sulzer) (27 plant species), Aphis (Toxoptera) aurantii Boyer de Fonscolombe and Brachycaudus (Brachycaudus) helichrysi (Kaltenbach) (26 plant species each) and Myzus (Myzus) ornatus Laing (25 plant species).

Honeydew associated with four common crop aphid species increases longevity of the parasitoid wasp, Bracon cephi (Hymenoptera: Braconidae)

Abstract The absence of sugar resources can be an important factor in limiting the success of parasitoids as biological control agents. Restoring vegetation complexity within agricultural landscapes has thus become a major focus of conservation biological control efforts, with a traditional emphasis on nectar resources. Aphid honeydew is also an important source of sugars that is infrequently considered. We carried out a laboratory experiment to examine the potential effects of honeydew from six different aphid species by crop species combinations on the longevity of Bracon cephi Gahan (Hymenoptera: Braconidae), the most important biological control of the wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), a major pest of wheat in the northern Great Plains of North America. The benefits of honeydew for parasitoid longevity varied significantly among different aphid and crop species, illustrating the complexity of these interactions. However, honeydew produced by four aphid species commonly found in wheat, pea, and canola crops significantly increased the longevity (by two- to threefold) of the parasitoid. The study suggests that honeydew provisioning could be an important mechanism underlying the benefits of crop diversification to support biological control that merits further research.

Predatory capacity and intraguild interaction between aphidophagous predators in the control of rose bush aphids

Chrysoperla externa (Hagen) and Hippodamia convergens (Guérin-Meneville) are voracious generalist predators, and important aphid control agents. In an environment containing a complex of species, the occurrence of intraguild interactions can interfere in the predator behavior and consumption. The aim of this work was to know the number of nymphs of Rhodobium porosum (Sanderson) and Macrosiphum rosae (Linnaeus) consumed by larvae of C. externa and H. convergens, and the interaction between these predators when confined together. First, second and third instar nymphs of R. porosum and M. rosae were provided in Petri dishes containing rose leaflets and second instar larvae of the predators. Intraguild interaction was studied in Petri dishes containing first instar nymphs of both aphid species and a second instar larva of C. externa plus one of H. convergens. A third treatment consisted of dishes containing a second instar larva of both predators maintained in the absence of prey. The evaluations took place throughout the entire instar of the predators. C. externa consumed a greater number of R. porosum nymphs and H. convergens a greater number of M. rosae nymphs. For both species of prey, the highest consumption was verified on the last day of evaluation. There was a positive interaction when the predator’s larvae were confined in the presence of aphid nymphs, with no mortality observed for any of them. In the absence of prey, there was 70% mortality of H. convergens larvae due to intraguild predation.

The Adult Tendency of Eleven-Spotted Ladybird, Coccinella undecimpunctata for Preference of Certain Type of Aphid

Ibrahim, A.K. 2023. The Adult Tendency of Eleven-Spotted Ladybird, Coccinella undecimpunctata for Preference of Certain Type of Aphid. Arab Journal of Plant Protection, 41(4): 369-374. https://doi.org/10.22268/AJPP-41.4.369374 This study explored the extent of eleven ladybirds preference to a specific aphid species, i.e., Aphis fabae, A. nerii, Macrosiphoniella sanborni and Hyalopterus pruni and the extent of the host plant and type of prey in attracting predators. Results obtained showed a preference of adult ladybird predators for H. pruni, Macrosiphoniella sanborni, Aphis nerii, whereas Aphis fabae was the least attractive and consumed by predators. The consumption rate of apricot aphid reached 23.66% in the presence of aphids and the host plant together. The most attraction to apricot leaves in the presence of the plant only was 55.90%. The time required for ladybirds to reach the first prey was 2.15 min for the apricot aphid in the presence of aphids and plants together. Furthermore, the ladybirds reached the prey within 1.30 minutes in the presence of aphids only. The predation efficiency of the four larval instars varied according to the type of aphids. It reached 86.30% for the fourth larval instar on apricot aphids and was the highest compared with the rest of the aphid species, which ranged between 7.10 and 84%. The general average predation efficiency values on aphids were 57.45% for H. pruni, 53.13% for Macrosiphoniella sanborni, 46.05% for A. nerii and 41.16% for A. fabae. The relative efficiency values for the larval instars reached 12.25, 42.27, 60.20 and 83.50%, respectively, for the first, second, third and fourth instars. This was confirmed by the high attraction of predatory ladybirds towards H. pruni and Macrosiphoniella sanborni, compared to Aphis nerii and Aphis fabea. The proportion of aphids consumed by ladybirds in the presence of the plant host was highest for H. pruni and lowest on Aphis fabea. Keywords: Aphids, ladybugs, plant host, predation efficiency