Acute and chronic insecticidal activity of a new mannose-binding lectin from Allium porrum against Acyrthosiphon pisum via an artificial diet

2009 ◽  
Vol 141 (1) ◽  
pp. 95-101 ◽  
Author(s):  
Amin Sadeghi ◽  
J.M. Van Damme ◽  
Katrien Michiels ◽  
Anita Kabera ◽  
Guy Smagghe
Keyword(s):  
Artificial Diet ◽  
Acyrthosiphon Pisum ◽  
Insect Pests ◽  
Integrated Management ◽  
Allium Porrum ◽  
Pea Aphids ◽  
Mannose Binding ◽  
Galanthus Nivalis ◽  
High Doses ◽  
Binding Lectin

AbstractIn view of the increasing use of plant proteins as valuable alternatives to chemical insecticides, the susceptibility of pea aphids, Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae), to three purified mannose-binding plant lectins was determined in an artificial-diet bioassay. The insecticidal activities of a new lectin, APA (Allium porrum L. (Liliaceae) agglutinin) from garden leek, were compared with those of GNA (Galanthus nivalis L. (Liliaceae) agglutinin) from snowdrop and ASA (Allium sativum L. agglutinin) from cultivated garlic. GNA and ASA showed acute toxicity to first-instar nymphs; LC50 values for GNA and ASA were 350 and 700 µg/mL, respectively. With APA, mortality was scored only at high doses. In chronic experiments, however, lower doses significantly reduced survival and fecundity of adults (P < 0.05). Aphids fed a diet containing APA at 100, 500, and 750 µg/mL showed a significant delay in reaching adulthood and no aphids survived beyond 19 days of development. The data support the potential application of APA in the integrated management of insect pests.

Subversion of alarm communication: Do plants habituate aphids to their own alarm signals?

2001 ◽  
Vol 79 (4) ◽  
pp. 737-740 ◽  
Author(s):  
Anca S Petrescu ◽  
Edward B Mondor ◽  
Bernard D Roitberg
Keyword(s):  
Artificial Diet ◽  
Alarm Pheromone ◽  
Acyrthosiphon Pisum ◽  
Alarm Signals ◽  
Pheromone Concentration ◽  
Pea Aphids ◽  
Before And After ◽  
Alarm Communication

When attacked by a predator, pea aphids, Acyrthosiphon pisum, emit an alarm pheromone, (E)-β-farnesene, which causes nearby conspecifics to disperse from the area. However, herbivore-damaged plants also emit (E)-β-farnesene. We hypothesized that plants release farnesene to habituate aphids, i.e., to disrupt their alarm-pheromone responses, perhaps to reduce herbivory by increasing parasitoid or predator efficacy. Thus, we addressed two questions: (1) Do aphids habituate to (E)-β-farnesene, and (2) Are they habituated at levels produced by aphid-infested plants? On an artificial diet devoid of farnesene, aphids were exposed to 10 ng/cm3 of (E)-β-farnesene or a hexane control over 24 h. Habituation was achieved, as dropping responses to 50 ng/cm3 of (E)-β-farnesene decreased after exposure. We then exposed aphids to 0.8 ng/cm3 of (E)-β-farnesene, a pheromone concentration emitted by plants, or a hexane control for 24 h. Their reaction to 38 ng/cm3 of (E)-β-farnesene, the maximum pheromone concentration found in aphid-cornicle droplets, was not significantly different before and after exposure. Thus, our hypothesis that plants emit farnesene to disrupt aphid alarm communication remains unsupported.

scholarly journals A highly infective plant-associated bacterium influences reproductive rates in pea aphids

2016 ◽  
Vol 3 (2) ◽  
pp. 150478 ◽  
Author(s):  
Tory A. Hendry ◽  
Kelley J. Clark ◽  
David A. Baltrus
Keyword(s):  
Pseudomonas Syringae ◽  
Acyrthosiphon Pisum ◽  
Dependent Manner ◽  
Bacterial Cells ◽  
Pea Aphids ◽  
Survival And Reproduction ◽  
Fecundity Compensation ◽  
Reproductive Rates ◽  
High Doses ◽  
Aphid Pathogen

Pea aphids, Acyrthosiphon pisum , have the potential to increase reproduction as a defence against pathogens, though how frequently this occurs or how infection with live pathogens influences this response is not well understood. Here we determine the minimum infective dose of an environmentally common bacterium and possible aphid pathogen, Pseudomonas syringae , to determine the likelihood of pathogenic effects to pea aphids. Additionally, we used P. syringae infection to investigate how live pathogens may alter reproductive rates. We found that oral bacterial exposure decreased subsequent survival of aphids in a dose-dependent manner and we estimate that ingestion of less than 10 bacterial cells is sufficient to increase aphid mortality. Pathogen dose was positively related to aphid reproduction. Aphids exposed to low bacterial doses showed decreased, although statistically indistinguishable, fecundity compared to controls. Aphids exposed to high doses reproduced significantly more than low dose treatments and also more, but not significantly so, than controls. These results are consistent with previous studies suggesting that pea aphids may use fecundity compensation as a response to pathogens. Consequently, even low levels of exposure to a common plant-associated bacterium may therefore have significant effects on pea aphid survival and reproduction.

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