Infected Aphids Research Articles

Screening of exotic and indigenous apple rootstocks for different horticultural traits

An experiment was carried out to find the suitable exotic as well as indigenous apple rootstocks for temperate zone of India. The rootstocks were screened on the basis of 11 important pomological traits. The data revealed that maximum numbers of primary and secondary roots were noted of 93.40, 92.76 in MM.106 and USA 106 and 92.0 noted in CITHrootstock- 01, respectively. Maximum length of primary roots (19.83cm) was recorded of EMLA 106 whereas shortest primary roots (6.47 cm) were recorded of ALNARP. The longest secondary roots (11.83cm) were found in M.27 and shortest secondary roots (2.10 cm) in ALNARP rootstock. Most of the indigenous apple rootstocks were having short to medium length of secondary roots. Leaf area was recorded highest (3.80cm2) in CITH-Apple rootstock-04 and smallest (1.96 cm2) of USA- 106. All the evaluated rootstocks have pink colored petiole except B-9, which has dark red color. Highest collar rot incidence was observed in M- 27 and M-26 and least in indigenous root stocks (CITH-Apple rootstocks). Highest wooly aphid infection was found in M-9, B-9, M-27, EMLA-106 and ALNARP whereas least infestation noted in M-26 and indigenous apple rootstock (CITH-ARS-01, CITH-ARS-02, CITH-ARS-03, CITH-ARS-04, CITH-ARS-, CITH-ARS-09 and CITH-ARS-10). Primary root length has positive correlation with secondary root numbers, secondary root length and leaf petiole length but negative correlation with leaf area.SAARC J. Agri., 14(2): 117-125 (2016)

Technology of mass multiplication of cereal aphids (Schizaphis graminum) using an aeroponic plant and dilution of the bioagent aphidius (Aphidius matricariae)

The results of research on the cultivation of fodder plants of barley and infection of plants with cereal aphids in the conditions of an aeroponics installation are given. The germination parameters are determined depending on the periodicity of the water supply of its volume and the mass of the seeds grown in the plant. In the conditions of the aeroponic plant, the reproduction of aphids is considered optimal if 5 individuals of phytophagous are released per barley plant. After seven days, the number of aphids increased to 42.5 individuals, while its high concentration was noted. When carrying out the infection of aphids propagated under the conditions of the aphids, the optimal parasite ratio: host = 1: 60. The degree of infection of aphids (mummified) was 84.2% on this variant.

Identification of Aphid Infection on Rape Pods Using Hyperspectral Imaging Combined with Image Processing

Identification of Aphid Infection on Rape Pods Using Hyperspectral Imaging Combined with Image Processing

The influence of facultative endosymbionts on honeydew carbohydrate and amino acid composition of the black bean aphid Aphis fabae

AbstractThe facultative endosymbionts Hamiltonella defensa and Regiella insecticola are commonly found in aphids. They are linked with various ecological benefits but generally occur at low prevalence, which indicates a possible harbouring cost. Little is known about how the presence of facultative endosymbionts is reflected in honeydew composition. Honeydew is the key mediator of the mutualism between aphids and their tending ants. The present study examines whether endosymbionts have an influence on aphid honeydew quality by comparing the amino acid and carbohydrate concentrations between infected and uninfected aphids. To this end, two genetic lines of the aphid Aphis fabae Scopoli are experimentally infected with different strains of Hamiltonella and Regiella. Infected aphids are shown to have reduced concentrations of amino acids in the honeydew compared with uninfected aphids. However, the presence of endosymbionts has no effect on the absolute amount of carbohydrates produced. Nevertheless, interclonal variation in honeydew composition between aphid genotypes is observed for both carbohydrate and amino acid production. These results imply that the nutritional value of honeydew depends on aphid genotype, as well as on the presence of secondary bacterial endosymbionts, which suggests that there is a physiological cost of harbouring endosymbionts and which could also impact aphid attractiveness to tending ants.

WATERMELON MOSAIC VIRUS OF PUMPKIN (Cucurbita maxima) FROM SULAWESI: IDENTIFICATION, TRANSMISSION, AND HOST RANGE

A mosaic disease of pumpkin (Cucurbita maxima) was spread widely in Sulawesi. Since the virus had not yet been identified, a study was conducted to identify the disease through mechanical inoculation, aphid vector transmission, host range, and electron microscopic test. Crude sap of infected pumpkin leaf samples was rubbed on the cotyledons of healthy pumpkin seedlings for mechanical inoculation. For insect transmission, five infective aphids were infected per seedling. Seedlings of eleven different species were inoculated mechanically for host range test. Clarified sap was examined under the electron microscope. Seeds of two pumpkin fruits from two different infected plants were planted and observed for disease transmission up to one-month old seedlings. The mosaic disease was transmitted mechanically from crude sap of different leaf samples to healthy pumpkin seedlings showing mosaic symptoms. The virus also infected eight cucurbits, i.e., cucumber (Cucumis sativus), green melon (Cucumis melo), orange/rock melon (C. melo), zucchini (Cucurbita pepo), pumpkin (Cucurbita maxima), water melon (Citrulus vulgaris), Bennicosa hispida, and blewah (Cucurbita sp.). Aphids transmitted the disease from one to other pumpkin seedlings. The virus was not transmitted by seed. The mosaic disease of pumpkin at Maros, South Sulawesi, was associated with flexious particles of approximately 750 nm length, possibly a potyvirus, such as water melon mosaic virus rather than papaya ringspot virus or zucchini yellow mosaic virus.

WATERMELON MOSAIC VIRUS OF PUMPKIN (Cucurbita maxima) FROM SULAWESI: IDENTIFICATION, TRANSMISSION, AND HOST RANGE

A mosaic disease of pumpkin (Cucurbita maxima) was spread widely in Sulawesi. Since the virus had not yet been identified, a study was conducted to identify the disease through mechanical inoculation, aphid vector transmission, host range, and electron microscopic test. Crude sap of infected pumpkin leaf samples was rubbed on the cotyledons of healthy pumpkin seedlings for mechanical inoculation. For insect transmission, five infective aphids were infected per seedling. Seedlings of eleven different species were inoculated mechanically for host range test. Clarified sap was examined under the electron microscope. Seeds of two pumpkin fruits from two different infected plants were planted and observed for disease transmission up to one-month old seedlings. The mosaic disease was transmitted mechanically from crude sap of different leaf samples to healthy pumpkin seedlings showing mosaic symptoms. The virus also infected eight cucurbits, i.e., cucumber (Cucumis sativus), green melon (Cucumis melo), orange/rock melon (C. melo), zucchini (Cucurbita pepo), pumpkin (Cucurbita maxima), water melon (Citrulus vulgaris), Bennicosa hispida, and blewah (Cucurbita sp.). Aphids transmitted the disease from one to other pumpkin seedlings. The virus was not transmitted by seed. The mosaic disease of pumpkin at Maros, South Sulawesi, was associated with flexious particles of approximately 750 nm length, possibly a potyvirus, such as water melon mosaic virus rather than papaya ringspot virus or zucchini yellow mosaic virus.

Plant and insect microbial symbionts alter the outcome of plant–herbivore–parasitoid interactions: implications for invaded, agricultural and natural systems

Summary Understanding how soil microbial communities influence plant interactions with other organisms, and how this varies with characteristics of the interacting organisms, is important for multiple systems. Solanum spp. are a suitable model for trophic interactions in studies of agricultural and natural systems and can also provide useful corollaries in invaded systems. This study examined the influence of soil mutualist arbuscular mycorrhizal (AM) fungi on growth of different Solanum types fed on by the potato aphid, Macrosiphum euphorbiae, in relation to the presence of the aphid facultative endosymbiont Hamiltonella defensa. Four Solanum types comprising two wild species, S. berthaultii and S. polyadenum, and two accessions of S. tuberosum, were grown with or without AM fungi and infested with one of four clonal lines of a single M. euphorbiae genotype (two with and two without H. defensa). Two experiments were conducted to (i) characterize plant responses to AM fungi and aphids and (ii) assess whether soil AM fungi could influence the success of the parasitoid wasp Aphidius ervi when attacking aphids reared on each Solanum type. In both experiments, similar patterns of plant biomass were observed in relation to AM fungal and aphid treatments. Solanum biomass depended on plant type and aphid infection with H. defensa. Plants exposed to aphids harbouring H. defensa had smaller root biomass, and therefore total plant biomass, compared to plants infested with H. defensa‐free aphids. M. euphorbiae performance varied with aphid clonal line, Solanum type and the presence of AM fungi. Parasitoid success, measured as the proportion of aphids from which a wasp emerged, was highest from aphids that had fed on plants colonized by AM fungi, although this result also varied with Solanum type and aphid clonal line. Synthesis. The presence of soil AM fungi, combined with within‐species plant and insect variation in key traits, can have subtle – but significant – effects on plant fitness and insect success. This study highlights the importance of exploring genotypic variation in plant and pest responses to soil microbiota to identify suitable biocontrol options.

SEM Study on Morphological Changes in <I>Metarhizium anisopliae</I> Infected <I>Aphis craccivora</I> Koch.

Morphological changes in Metarhizuim anisopliae (Metschnikoff) Sorokin infected cow pea aphid, Aphis craccivora Koch were studied by scanning electron microscope (SEM). Aphids were caged on paired lantern chimney over cowpea twigs dipped in conical flasks with water infected and inoculated with fungal propagules of M. anisopliae at the concentration of 1X10 6 spores /ml of water. Infected aphids were observed under SEM and it showed severe cuticular damage, abnormalities in sensory systems as well as deformation of all the body parts. The hydrophobic conidia of M. anisopliae were found to attach to all body regions. It was evident that mycelial growth and conidiophores with conidia of M. anisopliae covered the body surface and penetrates inside the body of infested aphid causing damage to the pest by disturbing its major physiological activities leading to its death.

SEM Study on Morphological Changes in <I>Metarhizium anisopliae</I> Infected <I>Aphis craccivora</I> Koch.

Morphological changes in <em>Metarhizuim anisopliae</em> (Metschnikoff) Sorokin infected cow pea aphid, <em>Aphis craccivora</em> Koch were studied by scanning electron microscope (SEM). Aphids were caged on paired lantern chimney over cowpea twigs dipped in conical flasks with water infected and inoculated with fungal propagules of <em>M. anisopliae</em> at the concentration of 1X10<sup>6</sup> spores /ml of water. Infected aphids were observed under SEM and it showed severe cuticular damage, abnormalities in sensory systems as well as deformation of all the body parts. The hydrophobic conidia of <em>M. anisopliae</em> were found to attach to all body regions. It was evident that mycelial growth and conidiophores with conidia of <em>M. anisopliae</em> covered the body surface and penetrates inside the body of infested aphid causing damage to the pest by disturbing its major physiological activities leading to its death.

The Effect of Applying Exogenous Salicylic Acid on Aphid Infection and its Influence on Histo-Physiological Traits and Thermal Imaging of Canola

Abstract Insect damage in canola adversely affects its productivity andquality and is considered one of the most important degrading factors in Egypt. The effect of foliar application of salicylic acid (SA) on aphid populations, growth and yield of canola (Brassica napus, L.) cv. serw 4 was the major goal of this study. Two experiments were conducted at the farm of Faculty of Agriculture, Suez Canal University, Ismailia, Egypt, during 2014 and 2015 seasons, to achieve this target. Each experiment included four levels of SA (0, 50, 100, 200 mg 1-1). The experimental results revealed that SA, at low concentration (50 mg 1-1), was an effective treatment for reduction the number of aphid populations and colony depth on the main inflorescence, contributed with reducing the thickness of secretory tissue of flower pedicel. The level of 50 mg 1-1 of SA-treated canola had the highest number of stomata cm-2, along with the lowest width of both stoma and its aperture. Thickness of xylem tissue and the number of xylem vessels bundle-1 in leaf midrib, reducing sugars and free amino acids was increased at 50 mg 1-1 SA, but free phenolics content did not affected significantly. Under controlled conditions, changes in temperature of infected leaves allowed the discrimination between healthy and infected areas in thermo-image, even before visible symptoms of aphid infestation appeared. The detection of modifications in plants or canopies, associated with low insect severity in the early stages of infestation, was crucial for the targeted, site-specific or on demand application of integrated aphid control. Canola, which was treated with 50 mg 1-1 of SA, gave 30.5 and 27.9 kg of oil ha-1 over the control. It was concluded that spraying of SA at 50 mg 1-1 was an effective elicitor to diminish the aphid numbers on canola inflorescence and improve its yield.

Lecanicillium longisporum on Cabbage Aphid (Brevicoryne brassicae): A New Record from Northeast India

Cabbage aphid (Brevicoryne brassicae) is an important pest of cabbage in Northeast India. Infected aphids were spotted on cabbage plants in Meghalaya, India. Morphological (light and scanning electron microscopy) and molecular characterisation of the fungus revealed it to be Lecanicillium longisporum. Pathogenicity tests were also conducted which yielded positive results.

Neozygites osornensis (Neozygitales: Neozygitaceae) Infecting Cinara sp. (Hemiptera: Aphididae) in Brazil.

The genus Neozygites has been known in Brazil until now only on mites, and this is its first report on aphids in Brazil. Tree-dwelling aphids (Cinara sp.) on a cypress tree were regularly monitored for entomopathogenic fungi in the city of Terezópolis de Goiás in Central Brazil between July 2014 and April 2015. During the survey, mycosed aphids were found attached to twigs. The fungus was identified morphologically as Neozygites osornensis. No in vitro cultures were established from infected aphids. The finding reported here suggests that special attention should be paid in the future for the possible occurrences of Neozygites species wherever cinaran aphids occur around the globe.

Prevalence of entomophthoralean fungi (Entomophthoromycota) of aphids in relation to developmental stages.

Transmission of fungal pathogens of aphids may be affected by the host developmental stage. Brassica and Lactuca sativa L. crops were sampled in Santa Fe, Argentina, to determine the prevalence of fungal-diseased aphids and investigate the differences between developmental stages of aphids. The fungal pathogens identified were Zoophthora radicans (Bref.) A. Batko, Pandora neoaphidis (Remaud. & Hennebert) Humber and Entomophthora planchoniana Cornu. Their prevalence on each crop was calculated. The numbers of infected aphids were significantly different between the different developmental stages on all crops except B. oleracea var. botrytis L. The entomophthoralean fungi identified are important mortality factors of aphids on horticultural crops in Santa Fe. The numbers of infected nymphs and adults were significantly different, nymphs being the most affected developmental stage. © 2015 Society of Chemical Industry.

Surveys of Viruliferous Alate Aphid of Plum pox virus in Prunus mume Orchards in Japan.

Plum pox virus (PPV) is transmitted by infected buds and aphids. It is important to analyze the outbreak trends and viruliferous rate of aphids in areas where the occurrence of PPV is reported, so as to develop strategies for disease control. Between April 2011 and December 2012, yellow insect-trapping adhesive plates were placed for 2 days at a time each week in an area where PPV is occurring in Japan. Outbreak trends were analyzed based on the trapped alate aphid samples, and up to 50 of them were tested per week to identify species and determine the rate of viruliferous specimens. Although the number of aphids varied according to survey year, three peaks were noticeable in each year. Based on the sequence data for the mitochondrial cytochrome c oxidase I region, approximately 40 different species of aphid were trapped in both years. Of the five dominant species of aphids identified during the 2 years, Aphis spiraecola was trapped in large numbers. PPV-positive aphids were higher in fall onward, when the total number of trapped aphids decreased, than in spring and summer, when a larger number of aphids was caught. PPV transmission tests using the most abundant species revealed that A. spiraecola, A. craccivora, A. gossypii, and Rhopalosiphum maidis were transmitters, although A. spiraecola is likely of epidemiological significance.

Interactions among vegetable-infesting aphids, the fungal pathogen Metarhizium anisopliae (Ascomycota: Hypocreales) and the predatory coccinellid Cheilomenes lunata (Coleoptera: Coccinellidae)

Entomopathogenic fungi are among biocontrol agents being considered for the control of aphids on a variety of crops. Predatory coccinellids, although generalist, are also among important natural enemies that must be conserved for aphid management. Laboratory studies were carried out to investigate the interaction between three vegetable-infesting aphids, Metarhizium anisopliae isolate ICIPE 62 and the coccinellid predator Cheilomenes lunata. At a concentration of 1 × 108 conidial ml–1, the fungus was found to cause mortality of 7.5% to C. lunata, compared to 2.5% mortality in the control at 10 days post-treatment. Female adult C. lunata to which fungus-infected aphids were offered as prey never accepted them as food source in non-choice bioassays. However, live and dead non-infected aphids were fed upon. In choice bioassay, a total of 1–3 out of 24 infected non-sporulating aphids per species (average of 0.1–0.4 aphids per arena) were consumed by 48 h-starved C. lunata within a period of 60 min, but avoided sporulating cadavers. Foraging adult C. lunata enhanced the spread of conidia of M. anisopliae from infected cadavers to fourth instars Aphis gossypii feeding on okra (0.8–15.0% mortality), Brevicoryne brassicae (3.3–15.0% mortality) and Lipaphis pseudobrassicae (0.8–14.2% mortality) on kale plants. Results of this study demonstrate compatibility between M. anisopliae and C. lunata, and could provide a sustainable strategy for effective management of aphids on crucifers and okra cropping systems.

Development and Reproduction of Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) Fed on Myzus persicae (Sulzer) (Hemiptera: Aphididae) Vectoring Potato leafroll virus (PLRV).

The aim of this study was to evaluate the biological parameters of Chrysoperla externa (Hagen) while feeding on Myzus persicae (Sulzer) acting as a vector of potato leafroll virus (PLRV). In laboratory experiments, three different diets were offered ad libitum to C. externa during the larval period: M. persicae fed on PLRV-infected potato leaves, M. persicae fed on uninfected potato leaves, and eggs of the factitious prey Anagasta kuehniella (Zeller) as the control. The following parameters were studied: the developmental time and survival rate of the larval and pupal stages, the sex ratio, the proportion of fertile females, female fecundity and egg viability, and the survival curve of the first 30 days after adult emergence. PLRV-infected aphids influenced the C. externa larval developmental time and survival compared to PLRV-uninfected aphids and A. kuehniella eggs. The pupal developmental time of C. externa was shorter when fed on aphids compared to A. kuehniella eggs, but no differences were recorded between the PLRV-infected and uninfected aphid diets. Additionally, no differences were observed for pupal survival and reproduction. However, adult survival was affected by the prey type, as 75% of C. externa control adults remained alive at an age of 30 days compared to 51 and 54% for those fed on PLRV-uninfected and infected aphids, respectively.

The Endosymbiont Arsenophonus Provides a General Benefit to Soybean Aphid (Hemiptera: Aphididae) Regardless of Host Plant Resistance (Rag).

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), invokes substantial chemical treatment and economic cost in North America. Resistant soybean genotypes hold promise as a low-impact control methodology, but soybean aphid "biotypes" capable of development on resistant soy cast doubt on the durability of soy resistance. We hypothesized that variation in soybean aphid ability to colonize resistant soy is partially attributable to a bacterial symbiont of soybean aphid, Arsenophonus. We used microinjection to manipulate Arsenophonus infection in both virulent and avirulent aphid biotypes, resulting in five pairs of infected versus uninfected isolines. These isolines were subjected to various population growth rate assays on resistant Rag versus susceptible soybean. We found that aphid virulence on Rag soybean was not dependent on Arsenophonus: virulent aphid biotypes performed well on Rag soybean, and avirulent aphid biotypes performed poorly on Rag soybean, regardless of whether Arsenophonus was present or not. However, we did find that Arsenophonus-infected clones on average performed significantly better than their paired uninfected isolines. This pattern was not consistently evident on every date for every clone, either in the population assays nor when we compared lifetime fecundity of individual aphids in a separate experiment. Nevertheless, this overall benefit for infected aphids may be sufficient to explain the high frequency of Arsenophonus infection in soybean aphids.

Herbivorous insect decreases plant nutrient uptake: the role of soil nutrient availability and association of below‐ground symbionts

1. Plants take nutrients from the rhizosphere via two pathways: (i) by absorbing soil nutrients directly via their roots and (ii) indirectly via symbiotic associations with nutrient‐providing microbes. Herbivorous insects can alter these pathways by herbivory, adding their excrement to the soil, and affecting plant–microbe associations.2. Little is known, however, about the effects of herbivorous insects on plant nutrient uptake. Greenhouse experiments with soybean, aphids, and rhizobia were carried out to examine the effects of aphids on plant nutrient uptake.3. First, the inorganic soil nitrogen and the sugar in aphid honeydew between aphid‐infected and ‐free plants were compared. It was found that aphid honeydew added 41 g m−2 of sugar to the soil, and that aphids decreased the inorganic soil nitrogen by 86%. This decrease may have been caused by microbial immobilisation of soil nitrogen followed by increased microbial abundance as a result of aphid honeydew.4. Second, nitrogen forms in xylem sap between aphid‐infected and ‐free plants were compared to examine nitrogen uptake. Aphids decreased the nitrogen uptake via both pathways, and strength of the impact on direct uptake via plant roots was greater than indirect uptake via rhizobia. The reduced nitrogen uptake by the direct pathway was as a result of microbial immobilisation, and that by the indirect pathway was probably because of the interaction of microbial immobilisation and carbon stress, which was caused by aphid infection.5. The present results demonstrate that herbivorous insects can negatively influence the two pathways of plant nutrient uptake and alter their relative importance.

Prevalence of entomophthoralean fungi (Entomophthoromycota) of aphids (Hemiptera: Aphididae) on solanaceous crops in Argentina

Solanum melongena L. and Capsicum annuum L. were sampled in Argentina to determine the prevalence of fungal diseased aphids. The pathogens identified were Pandora neoaphidis (Remaudière & Hennebert) Humber and Zoophthora radicans (Brefeld) Batko (Entomophthorales: Entomophthoraceae) on aphids from eggplants; and P. neoaphidis and Entomophthora planchoniana Cornu (Entomophthorales: Entomophthoraceae) on aphids from peppers. The highest fungal prevalence was 45.5% (n=2296) and 98.1% (n=3212) from aphids on eggplants and peppers, respectively. In both crops, significant differences were found on number of infected aphids among developmental stages. P.neoaphidis and E. planchoniana caused epizootics in M. persicae.

Seasonal phenology of Amphorophora agathonica (Hemiptera: Aphididae) and spread of viruses in red raspberry in Washington.

Amphorophora agathonica (Hottes) is the primary vector of aphid-transmitted viruses in red raspberry in the Pacific Northwest region of the United States. To better understand the biology of the aphid, we estimated the lower developmental threshold and studied the seasonal activity of A. agathonica in commercial fields in northern Washington state. In addition, we monitored the spread of raspberry viruses (raspberry latent virus and raspberry leaf mottle virus, RLMV) to determine how rapidly fields became infected and whether there was a relationship between aphid presence and infection. The lower developmental threshold of A. agathonica was estimated to be 2.7°C. In the field, apterous and alate aphid populations began rapidly increasing at ≍800 growing degree-days and peaked at 1,050 growing degree-days. RLMV spread rapidly, with 30-60% of plants in four different commercial fields testing positive after three growing seasons. There was no discernible relationship between the presence or abundance of aphids based on 10 leaves sampled per plant location, and the odds of that plant becoming infected with RLMV.