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Aphid

About: Aphid is a research topic. Over the lifetime, 11380 publications have been published within this topic receiving 229721 citations. The topic is also known as: Aphidoidea & plant lice.


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Journal ArticleDOI
TL;DR: This goal was to determine whether insecticides considered reduced-risk by the Environmental Protection Agency could protect soybean yield from A. glycines herbivory while having a limited impact on the aphid's natural enemies.
Abstract: Insect predators in North America suppress Aphis glycines Matsumura (Hemiptera: Aphididae) populations; however, insecticides are required when populations reach economically damaging levels. Currently, insecticides used to manage A. glycines are broad-spectrum (pyrethroids and organophosphates), and probably reduce beneficial insect abundance in soybean, Glycine max (L.) Merr. Our goal was to determine whether insecticides considered reduced-risk by the Environmental Protection Agency could protect soybean yield from A. glycines herbivory while having a limited impact on the aphid's natural enemies. We compared three insecticides (imidacloprid, thiamethoxam, and pymetrozine,) to a broad-spectrum insecticide (λ-cyhalothrin) and an untreated control using two application methods. We applied neonicotinoid insecticides to seeds (imidacloprid and thiamethoxam) as well as foliage (imidacloprid); pymetrozine and λ-cyhalothrin were applied only to foliage. Foliage-applied insecticides had lower A. glycines populations and higher yields than the seed-applied insecticides. Among foliage-applied insecticides, pymetrozine and imidacloprid had an intermediate level of A. glycines population and yield protection compared with λ-cyhalothrin and the untreated control. We monitored natural enemies with yellow sticky cards, sweep-nets, and direct observation. Before foliar insecticides were applied (i.e., before aphid populations developed) seed treatments had no observable effect on the abundance of natural enemies. After foliar insecticides were applied, differences in natural enemy abundance were observed when sampled with sweep-nets and direct observation but not with yellow sticky cards. Based on the first two sampling methods, pymetrozine and the foliage-applied imidacloprid had intermediate abundances of natural enemies compared with the untreated control and λ-cyhalothrin.

87 citations

Journal ArticleDOI
Gary C. Chang1
TL;DR: In this paper, the authors conducted laboratory experiments quantifying the behavior and effectiveness of predator species used either singly or in combination to control bean aphids, Aphis fabae Scopoli.
Abstract: An open question in biological control concerns the value of using multiple as opposed to a single species of natural enemies. To find out how the mechanisms by which multiple biocontrol agents might interact, I conducted laboratory experiments quantifying the behavior and effectiveness of predator species used either singly or in combination to control bean aphids, Aphis fabae Scopoli. The predators were larvae of a lacewing, Chrysoperla plorabunda (Fitch), and the sevenspotted lady beetle, Coccinella septempunctata L. The experiments consisted of 4 treatments tested in a 2 X 2 factorial design crossing 0 or 1 first-instar C. plorabunda with 0 or 1 first-instar C. septempunctata per fava bean plant, Vicia faba L. I also tested 2 additional treatments of 2 larvae of a single species, for a total of 6 treatments. The predators slowed the growth of aphid populations ; no evidence of interaction between the predator species could be seen in terms of their effects on the sizes of the final aphid populations. This result may be explained by the finding that larvae of C. plorabunda and C. septempunctata differed significantly in where they were most frequently found on the plant. No clear evidence for intraguild predation was found. Thus, the majority of the data indicated that C. plorabunda and C. septempunctata did not have significant interactions.

87 citations

Journal ArticleDOI
TL;DR: The present study demonstrates the potential of barley cystatins to interfere with the performance of two aphid species by inhibiting in vitro the activity of cathepsin L- and/or B-like proteinases.
Abstract: Cystatins from plants have been implicated in plant defense towards insects, based on their role as inhibitors of heterologous cysteine-proteinases. We have previously characterized thirteen genes encoding cystatins (HvCPI-1 to HvCPI-13) from barley (Hordeum vulgare), but only HvCPI-1 C68 → G, a variant generated by direct-mutagenesis, has been tested against insects. The aim of this study was to analyze the effects of the whole gene family members of barley cystatins against two aphids, Myzus persicae and Acyrthosiphon pisum. All the cystatins, except HvCPI-7, HvCPI-10 and HvCPI-12, inhibited in vitro the activity of cathepsin L- and/or B-like proteinases, with HvCPI-6 being the most effective inhibitor for both aphid species. When administered in artificial diets, HvCPI-6 was toxic to A. pisum nymphs (LC50 = 150 μg/ml), whereas no significant mortality was observed on M. persicae nymphs up to 1000 μg/ml. The effects of HvCPI-6 ingestion on A. pisum were correlated with a decrease of cathepsin B- and L-like proteinase activities. In the case of M. persicae, there was an increase of these proteolytic activities, but also of the aminopeptidase-like activity, suggesting that this species is regulating both target and insensitive enzymes to overcome the effects of the cystatin. To further analyze the potential of barley cystatins as insecticidal proteins against aphids, Arabidopsis plants expressing HvCPI-6 were tested against M. persicae. For A. pisum, which does not feed on Arabidopsis, a combined diet-Vicia faba plant bioassay was performed. A significant delay in the development time to reach the adult stage was observed in both species. The present study demonstrates the potential of barley cystatins to interfere with the performance of two aphid species.

87 citations

Journal ArticleDOI
TL;DR: The role of semiochemicals in mediating intraguild interactions between the seven-spot ladybird, Coccinella septempunctata, and the aphid parasitoid, Aphidius ervi, was investigated and hydrocarbons identified induced avoidance behavior by female parasitoids.
Abstract: The role of semiochemicals in mediating intraguild interactions between the seven-spot ladybird, Coccinella septempunctata, and the aphid parasitoid, Aphidius ervi, was investigated. Female parasitoids avoided leaves visited by C. septempunctata adults and larvae during the previous 24 hr. Ethanol extracts of C. septempunctata adults and larvae also induced avoidance responses by A. ervi. Two of the hydrocarbons identified by gas chromatography (GC) and coupled GC-mass spectrometry (GC-MS), n-tricosane (C23H48), and n-pentacosane (C25H52), when tested individually at levels found in the adult extract, induced avoidance by A. ervi. Further investigation of the larvae extract, and footprint chemicals deposited by adults in glass Petri dishes, confirmed the presence of the hydrocarbons. Parasitism rates of the pea aphid, Acyrthosiphon pisum, on broad bean plants, Vicia faba, which had been sprayed with a mixture of the chemicals, were lower than those on control plants. The effect, however, was no longer evident if parasitoid foraging was delayed by 24 hr after the plants were treated. The ecological significance of intraguild avoidance behavior and implications for possible use of the semiochemicals involved in future biological control programs are discussed.

87 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023387
20221,082
2021337
2020393
2019373
2018382