Field evaluation of lucerne (Medicago sativa L.) for resistance to aphids in northern China

2006 ◽  
Vol 57 (4) ◽  
pp. 471 ◽  
Author(s):  
C. G. He ◽  
X. G. Zhang
Keyword(s):  
Field Experiments ◽  
Acyrthosiphon Pisum ◽  
Early Stage ◽  
Damage Index ◽  
Field Evaluation ◽  
Northern China ◽  
Aphid Species ◽  
Gansu Province ◽  
Lanzhou City ◽  
Aphis Craccivora Koch

Resistance of 9 lucerne cultivars and lines of predominantly overseas introductions to an aphid complex was evaluated in field experiments at Lanzhou city in Gansu province of northern China in 2004. The aphid complex, consisting of 3 aphid species, the spotted alfalfa aphid (SAA) Therioaphis trifolii Monell, black bean aphid (BBA) Aphis craccivora Koch, and pea aphid (PA) Acyrthosiphon pisum Harris, was found to be dominated by BBA at the early stage of plant growth in spring and by SAA at other stages. Plants infested by SAA showed the symptoms of either chlorotic leaf veins or yellow leaf. Cultivars performed similarly in Gansu as in their country of origin, with minor differences (e.g. Hunter River). ‘Aphid damage index’ and ‘% of resistant plants’ were found to be useful parameters for specifying the resistance of a given cultivar to the aphid complex. Based on the ‘% of resistant plants’, cvv. HA–3, Cropper 9, 8925MF, SARDI 7, and SARDI 10 were classified as highly resistant; HA–1 and Gannong 3, resistant; Jindera, moderately resistant; and Hunter River, low resistance.

The effect of short-term aphid feeding on the partitioning of 14CO2 photoassimilate in three legume species

1987 ◽  
Vol 65 (4) ◽  
pp. 666-672 ◽  
Author(s):  
C. D. B. Hawkins ◽  
M. I. Whitecross ◽  
M. J. Aston
Keyword(s):  
Acyrthosiphon Pisum ◽  
Aphid Species ◽  
Unit Weight ◽  
Short Term ◽  
Garden Pea ◽  
Aphis Craccivora Koch ◽  
Aphid Feeding ◽  
Lateral Branches ◽  
Species Specific ◽  
Partitioning Pattern

The short-term effects of the feeding of cowpea aphids (Aphis craccivora Koch) and pea aphids (Acyrthosiphon pisum (Harris)), both Homoptera: Aphididae, on 14C translocation and plant growth of broadbean (Vicia faba L. cv. Aquadulce), cowpea (Vigna unguiculata (L.) Walp. cv. Caloona), and garden pea (Pisum sativum L. cv. Victory Freezer) seedlings were investigated, but not all plant–aphid combinations were utilized. Within 10 days of infestation, aphid feeding reduced the flux of translocate to the roots, changed the assimilate partitioning pattern in affected shoots, and apparently induced assimilate sources to become assimilate sinks. Cowpea aphid feeding also caused more lateral branches to be formed in broadbean. Some of these effects may be related to the imbibing of translocate by aphids, while other effects may result from a series of interactions involving substances in the saliva of aphids, plant hormones, and the assimilate ratio of sources–sinks. The amount of radioactivity found per unit weight of aphid tissue increased between days 5 and 10 in all four plant–aphid combinations. This may indicate that the nymphs were incapable of feeding on the larger phloem elements. Except for the decreased rate of translocation to the roots, the effect of aphid feeding on translocation is plant–aphid species specific.

Incidence of Aphids (Homoptera: Aphididae) and Associated Potyviruses in Summer Squash in Arkansas

1993 ◽  
Vol 28 (1) ◽  
pp. 73-81 ◽  
Author(s):  
C. A. Hander ◽  
P. J. McLeod ◽  
H. A. Scott
Keyword(s):  
Acyrthosiphon Pisum ◽  
Aphis Gossypii ◽  
Severe Infection ◽  
Aphid Species ◽  
Watermelon Mosaic Virus ◽  
South Central ◽  
Summer Squash ◽  
Close Proximity ◽  
Aphis Craccivora Koch ◽  
Marketable Fruit

A field study conducted in two Arkansas locations determined that five aphid species, Aphis craccivora Koch, Aphis gossypii Glover, Acyrthosiphon pisum (Harris), Rhopalosiphum maidis (Fitch) and Myzus persicae (Sulzer), were associated with yellow summer squash, Cucurbita pepo, L. Each aphid species vectors potyviruses of cucurbits. Although aphids were readily trapped with water and sticky flag traps, few aphids were observed on plants, and no vigorous aphid colonies were detected. In south central Arkansas (Benton), no virus-infected plants were observed in early plantings. Watermelon mosaic virus was detected in late squash plantings at Benton and varied from 0 to 23.2% of the total plants. In western Arkansas (Mulberry), papaya ringspot virus rapidly infected summer squash and resulted in complete loss of marketable fruit. The rapid and severe infection was attributed to close proximity of an infected squash planting.

Aphid parasitoids (Hymenoptera: Braconidae: Aphidiinae) in cultivated and non-cultivated areas of Markazi Province, Iran

Biologia ◽  
2013 ◽  
Vol 68 (5) ◽  
Author(s):  
Mahmoud Alikhani ◽  
Ali Rezwani ◽  
Petr Starý ◽  
Nickolas Kavallieratos ◽  
Ehsan Rakhshani
Keyword(s):  
Acyrthosiphon Pisum ◽  
Abundant Species ◽  
Diversity Indices ◽  
Aphid Species ◽  
Diaeretiella Rapae ◽  
Plant Associations ◽  
Aphid Parasitoids ◽  
Aphis Craccivora Koch ◽  
Host Aphid ◽  
Lysiphlebus Cardui

AbstractThe fauna of aphid parasitoids (Hymenoptera: Braconidae: Aphidiinae), as well as their diversity and tritrophic (parasitoid-host aphid-host plant) associations in cultivated and non-cultivated areas of Markazi province, was studied during 2004–2009. Thirty species of Aphidiinae belonging to 9 genera were identified. There are presented, in total, 73 associations with 32 host aphids occurring on 42 host plants. Five parasitoid-aphid associations are newly recorded from Iran. Lysiphlebus cardui (Marshall) is newly recorded for the fauna of Iran. Lysiphlebus fabarum (Marshall) and Diaeretiella rapae (M’Intosh) were the most abundant species in non-cultivated (72.96%) and cultivated (41.17%) areas, respectively. In the non-cultivated areas, L. fabarum was found on eight aphid species, while in cultivated areas it was only found on Aphis craccivora Koch. In cultivated areas, Sitobion avenae (F.) has the greatest diversity of parasitoids (Shanon-Weiner H = 0.875) whereas in non-cultivated areas the greatest diversity of parasitoids was recorded upon Acyrthosiphon pisum (Harris) (Shanon-Weiner H = 1.149). Significant differences were found between diversity of two ecosystems based on the overall diversity indices. Both species diversity and evenness were greater in cultivated ecosystems. The results are discussed in relation to the over-all parasitoid-aphid-plant associations in the area.

scholarly journals Sustainable laser-based technology for insect pest control

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. Gaetani ◽  
V. Lacotte ◽  
V. Dufour ◽  
A. Clavel ◽  
G. Duport ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Acyrthosiphon Pisum ◽  
Early Stage ◽  
Low Cost ◽  
Insect Pest ◽  
Rhopalosiphum Padi ◽  
Lethal Dose ◽  
Aphid Species ◽  
Promising Alternative ◽  
Reliable Solution

AbstractAphids damage directly or indirectly cultures by feeding and spreading diseases, leading to huge economical losses. So far, only the use of pesticides can mitigate their impact, causing severe health and environmental issues. Hence, innovative eco-friendly and low-cost solutions must be promoted apart from chemical control. Here, we have investigated the use of laser radiation as a reliable solution. We have analyzed the lethal dose required to kill 90% of a population for two major pest aphid species (Acyrthosiphon pisum and Rhopalosiphum padi). We showed that irradiating insects at an early stage (one-day old nymph) is crucial to lower the lethal dose without affecting plant growth and health. The laser is mostly lethal, but it can also cause insect stunting and a reduction of survivors’ fecundity. Nevertheless, we did not notice any significant visible effect on the offspring of the surviving irradiated generation. The estimated energy cost and the harmless effect of laser radiation on host plants show that this physics-based strategy can be a promising alternative to chemical pesticides.

scholarly journals Evaluation of Damage Process of a Coating by Using Nonlinear Ultrasonic Method

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 440
Author(s):  
Chunguang Xu ◽  
Lei He ◽  
Shiyuan Zhou ◽  
Dingguo Xiao ◽  
Pengzhi Ma
Keyword(s):  
Tensile Stress ◽  
Order Parameter ◽  
Evaluation Method ◽  
Early Stage ◽  
Ultrasonic Method ◽  
Nonlinear Coefficient ◽  
Damage Index ◽  
Second Order ◽  
External Loading ◽  
Nonlinear Ultrasonic

During the service or external loading of the surface coating, the damage accumulation may develop in the coating or at the interface between the substrate and the coating, but it is difficult to measure directly in the early stage, so the acoustic nonlinear parameters are used as the early damage index of the coating. In this paper, the nonlinear wave motion equation is solved by the perturbation method and the new relationship between the relative ratio of second-order parameter and third-order parameter was derived. The nonlinear ultrasonic testing system is used to detect received signals during tensile testing of for the specimen with Al2O3 coatings. It is found that when the stress is less than 260 MPa, the appearance of the coating has no obvious change, but the nonlinear coefficients measured by the experiment increase with the increase of the tensile stress. By comparing the curves of nonlinear coefficients and stress respectively, the fluctuation of curves the second-order nonlinear coefficient A2 and the relative nonlinear coefficient β′ to stress is relatively small, and close to the linear relationship with the tensile stress, which indicates that the two parameters of the specimen with Al2O3 coatings are more sensitive to the bonding conditions, and can be used as an evaluation method to track the coating damage.

scholarly journals Intraspecific variation in immune gene expression and heritable symbiont density

2021 ◽  
Vol 17 (4) ◽  
pp. e1009552
Author(s):  
Holly L. Nichols ◽  
Elliott B. Goldstein ◽  
Omid Saleh Ziabari ◽  
Benjamin J. Parker
Keyword(s):  
Gene Expression ◽  
Acyrthosiphon Pisum ◽  
Aphid Species ◽  
F1 Hybrids ◽  
Immune Gene ◽  
Immune Genes ◽  
Immune Mechanisms ◽  
Immune Gene Expression ◽  
Host Microbe Interactions ◽  
And Function

Host genetic variation plays an important role in the structure and function of heritable microbial communities. Recent studies have shown that insects use immune mechanisms to regulate heritable symbionts. Here we test the hypothesis that variation in symbiont density among hosts is linked to intraspecific differences in the immune response to harboring symbionts. We show that pea aphids (Acyrthosiphon pisum) harboring the bacterial endosymbiontRegiella insecticola(but not all other species of symbionts) downregulate expression of key immune genes. We then functionally link immune expression with symbiont density using RNAi. The pea aphid species complex is comprised of multiple reproductively-isolated host plant-adapted populations. These ‘biotypes’ have distinct patterns of symbiont infections: for example, aphids from theTrifoliumbiotype are strongly associated withRegiella. Using RNAseq, we compare patterns of gene expression in response toRegiellain aphid genotypes from multiple biotypes, and we show thatTrifoliumaphids experience no downregulation of immune gene expression while hostingRegiellaand harbor symbionts at lower densities. Using F1 hybrids between two biotypes, we find that symbiont density and immune gene expression are both intermediate in hybrids. We propose that in this system,Regiellasymbionts are suppressing aphid immune mechanisms to increase their density, but that some hosts have adapted to prevent immune suppression in order to control symbiont numbers. This work therefore suggests that antagonistic coevolution can play a role in host-microbe interactions even when symbionts are transmitted vertically and provide a clear benefit to their hosts. The specific immune mechanisms that we find are downregulated in the presence ofRegiellahave been previously shown to combat pathogens in aphids, and thus this work also highlights the immune system’s complex dual role in interacting with both beneficial and harmful microbes.

scholarly journals Incorporating biomarkers in ecological risk assessment of chemical contaminants of soils

2007 ◽  
Vol 26 (2) ◽  
pp. 120-137
Author(s):  
A. J. Reinecke ◽  
S. A. Reinecke ◽  
M. S. Maboeta ◽  
J. P. Odendaal ◽  
R. Snyman
Keyword(s):  
Risk Assessment ◽  
South African ◽  
Field Experiments ◽  
Early Stage ◽  
Population Level ◽  
Diagnostic Tools ◽  
Future Research ◽  
Chemical Contaminants ◽  
Toxic Response ◽  
Future Research Directions

Soil is an important but complex natural resource which is increasingly used as sink for chemicals. The monitoring of soil quality and the assessment of risks posed by contaminants have become crucial. This study deals with the potential use of biomarkers in the monitoring of soils and the assessment of risk resulting from contamination. Apart from an overview of the existing literature on biomarkers, the results of various of our field experiments in South African soils are discussed. Biomarkers may have potential in the assessment of risk because they can indicate at an early stage that exposure has taken place and that a toxic response has been initiated. It is therefore expected that early biomarkers will play an increasing role as diagnostic tools for determining exposure to chemicals and the resulting effects. They may have predictive value that can assist in the prevention or minimising of risks. The aim of this study was to investigate the possibilities of using our results on biomarker responses of soil dwelling organisms to predict changes at higher organisational levels (which may have ecological implications). Our recent experimental results on the evaluation of various biomarkers in both the laboratory and the field are interpreted and placed in perspective within the broader framework of response biology. The aim was further to contribute to the development and application of biomarkers in regulatory risk assessment schemes of soils. This critical review of our own and recent literature on biomarkers in ecotoxicology leads to the conclusion that biomarkers can, under certain conditions, be useful tools in risk assessment. Clear relationships between contamination loads in soil organisms and certain biomarker responses were determined in woodlice, earthworms and terrestrial snails. Clear correlations were also established in field experiments between biomarker responses and changes at the population level. This indicated that, in spite of the fact that direct mechanistic links are still not clarified, biomarkers may have the potential to provide early indications of forthcoming changes at higher organisational levels. Ways are proposed in which biomarkers could be used in the future in risk assessment schemes of soils and future research directions are suggested. 

scholarly journals Relative toxicity of some insecticides and azadirachtin against four crop infesting aphid species

1970 ◽  
Vol 27 ◽  
pp. 31-34
Author(s):  
M Khalequzzaman ◽  
Jesmun Nahar
Keyword(s):  
Myzus Persicae ◽  
Aphis Gossypii ◽  
Aphid Species ◽  
Aphis Craccivora ◽  
Lipaphis Erysimi ◽  
Relative Toxicity ◽  
Plant Origin ◽  
Residual Film ◽  
Aphis Gossypii Glover ◽  
Aphis Craccivora Koch

Indirect application was used to assay the toxicity of five insecticides; viz. malathion, carbosulfan, cymbush, imidacloprid and azadirachtin against four important crop infesting aphid species, Aphis craccivora Koch, Aphis gossypii Glover, Myzus persicae (Sulzer) and Lipaphis erysimi (Kaltenbach), reared on bean, brinjal, potato and cauliflower plants respectively. Residual film technique was applied by bringing leaves with tested aphids of the vegetable plants in the laboratory. Malathion was the least toxic to all aphids having LC50 as 327.97, 333.92, 305.26 and 313.77 μg cm-2 for A. craccivora, A. gossypii, M. persicae and M. persicae respectively. Cypermethrin was the most toxic showing LC50 as 12.55, 12.29, 12.55 and 12.10 μg cm-2 in the above mentioned species of aphid respectively. Carbosulfan and imidacloprid showed moderate toxicity. Azadirachtin as a natural plant origin insecticide proved to be the most toxic having LC50 as 0.41 μg cm-2 for A. craccivora, 0.34 μg cm-2 for A. gossypii and 0.44 μg cm-2 for both M. persicae and L. erysimi. Key words: Insecticide, toxicity, azadirachtin, Aphis craccivora, Aphis gossypii, Myzus persicae, Lipaphis erysimi   doi:10.3329/ujzru.v27i0.1950 Univ. j. zool. Rajshahi Univ. Vol. 27, 2008 pp. 31-34

scholarly journals Chilling Requirement Validation and Physiological and Molecular Responses of the Bud Endodormancy Release in Paeonia lactiflora ‘Meiju’

2021 ◽  
Vol 22 (16) ◽  
pp. 8382
Author(s):  
Runlong Zhang ◽  
Xiaobin Wang ◽  
Xiaohua Shi ◽  
Lingmei Shao ◽  
Tong Xu ◽  
...  
Keyword(s):  
Southern China ◽  
Early Stage ◽  
Northern China ◽  
Morphological Observation ◽  
Release Mechanism ◽  
Regulation Mechanism ◽  
Paeonia Lactiflora ◽  
Poor Growth ◽  
Herbaceous Peony ◽  
Cultivar Screening

The introduction of herbaceous peony (Paeonia lactiflora Pall.) in low-latitude areas is of great significance to expand the landscape application of this world-famous ornamental. With the hazards of climate warming, warm winters occurs frequently, which makes many excellent northern herbaceous peony cultivars unable to meet their chilling requirements (CR) and leads to their poor growth and flowering in southern China. Exploring the endodormancy release mechanism of underground buds is crucial for improving low-CR cultivar screening and breeding. A systematic study was conducted on P. lactiflora ‘Meiju’, a screened cultivar with a typical low-CR trait introduced from northern China, at the morphological, physiological and molecular levels. The CR value of ‘Meiju’ was further verified as 677.5 CUs based on the UT model and morphological observation. As a kind of signal transducer, reactive oxygen species (ROS) released a signal to enter dormancy, which led to corresponding changes in carbohydrate and hormone metabolism in buds, thus promoting underground buds to acquire strong cold resistance and enter endodormancy. The expression of important genes related to ABA metabolism, such as NCED3, PP2C, CBF4 and ABF2, reached peaks at the critical stage of endodormancy release (9 January) and then decreased rapidly; the expression of the GA2ox8 gene related to GA synthesis increased significantly in the early stage of endodormancy release and decreased rapidly after the release of ecodormancy (23 January). Cytological observation showed that the period when the sugar and starch contents decreased and the ABA/GA ratio decreased was when ‘Meiju’ bud endodormancy was released. This study reveals the endodormancy regulation mechanism of ‘Meiju’ buds with the low-CR trait, which lays a theoretical foundation for breeding new herbaceous peony cultivars with the low-CR trait.

UNITED STATES COAST GUARD ARCTIC OIL-POLLUTION PROGRAM*

1975 ◽  
Vol 1975 (1) ◽  
pp. 259-264
Author(s):  
J.H. Getman
Keyword(s):  
Oil Recovery ◽  
Field Experiments ◽  
Oil Pollution ◽  
Field Evaluation ◽  
Coast Guard ◽  
Cold Weather ◽  
United States Coast Guard ◽  
Surveillance And Response ◽  
Arctic Pollution ◽  
Arctic Conditions

ABSTRACT With the burgeoning forecasts of oil production and transportation in the cold weather regions-especially Alaska-expectations of spills in the fragile and hostile arctic environment must increase. The Coast Guard, responsible for maritime pollution control, has stepped up its arctic pollution surveillance and response research and development Field experiments on the behavior of oil-one under summer conditions in 1970, and another under winter conditions in 1972-have been run. These indicated that oil spreads at a much slower rate under arctic conditions, and that it pooled on and under the ice. Oil is quickly covered by snow, but the resulting mulch is easily handled by mechanical means. Burning was always a readily available and effective alternate means of removal. Off-the-shelf equipment was evaluated in 1973, resulting in a number of conclusions concerning barriers and moorings, oil recovery systems, and personnel. Based on this field evaluation, there will be additional oil/ice tests of recovery devices.

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