Variations in chemical defences and patterns of natural enemy attack between native and introduced populations of fireweed ( Senecio madagascariensis ): Implications for biological control

2021 ◽  
Author(s):  
Daniella Egli ◽  
Kerinne J. Harvey ◽  
Ben D. Moore ◽  
Christopher Mitchell ◽  
Terence Olckers
2021 ◽  
Author(s):  
Steven E Naranjo ◽  
James R Hagler ◽  
John A Byers

Abstract Conservation biological control is a fundamental tactic in integrated pest management (IPM). Greater biological control services can be achieved by enhancing agroecosystems to be more favorable to the presence, survival, and growth of natural enemy populations. One approach that has been tested in numerous agricultural systems is the deployment of synthetic chemicals that mimic those produced by the plant when under attack by pests. These signals may attract arthropod natural enemies to crop habitats and thus potentially improve biological control activity locally. A 2-yr field study was conducted in the cotton agroecosystem to evaluate the potential of synthetic methyl salicylate (MeSA) to attract native arthropod natural enemies and to enhance biological control services on two key pests. Slow-release packets of MeSA were deployed in replicated cotton plots season long. The abundance of multiple taxa of natural enemies and two major pests were monitored weekly by several sampling methods. The deployment of MeSA failed to increase natural enemy abundance and pest densities did not decline. Predator to prey ratios, used as a proxy to estimate biological control function, also largely failed to increase with MeSA deployment. One exception was a season-long increase in the ratio of Orius tristicolor (White) (Hemiptera: Anthocoridae) to Bemisia argentifolii Bellows and Perring (= Bemisia tabaci MEAM1) (Hemiptera: Aleyrodidae) adults within the context of biological control informed action thresholds. Overall results suggest that MeSA would not likely enhance conservation biological control by the natural enemy community typical of U.S. western cotton production systems.


1956 ◽  
Vol 47 (4) ◽  
pp. 685-702 ◽  
Author(s):  
F. J. Simmonds

The biology and general ecology ofMelittomma insulareFairm. in the Seychelles is briefly described and the difficulties in the biological control of this pest are stressed.As much information as possible was obtained concerning the species of the little-known family Lymexylonidae, particularly with regard to their biology, which in most cases has not been investigated. Several species might warrant further investigation with a view to providing natural enemies for use againstM. insulare, but in general what is known of their biology does not afford much hope that an effective parasite or predator will be found.The biology ofAtractocerus brasiliensisLep. & Serv. was investigated in detail in Trinidad but no natural enemy was found.The only possibility is thatRhizophagus dispar(Payk.), recorded as attackingHylecoetus dermestoides(L.) in England, might also attack the eggs ofM. insulare.


Weed Science ◽  
1995 ◽  
Vol 43 (3) ◽  
pp. 504-513 ◽  
Author(s):  
Scott J. Nissen ◽  
Robert A. Masters ◽  
Donald J. Lee ◽  
Martha L. Rowe

DNA-based molecular markers may provide information about introduced weedy species that would be useful in biological weed control efforts. Chloroplast DNA restriction fragment length polymorphisms (cpDNA RFLP) and random amplified polymorphic DNA (RAPD) analysis are two DNA-based marker techniques that can provide estimates of genetic variation in native and introduced populations of weedy species. Profiles provided by these techniques could furnish the necessary information to determine the geographic origins of introduced species and provide evidence for multiple introductions. Although DNA-based markers would not necessarily identify the genetic basis for host-pest compatibility, they would enable identification of specific host genotypes. Current criteria for selecting a weedy species as a target for biological control are primarily political and economic. The importance of genetic diversity and population structure in determining the vulnerability of plant populations to insects or diseases has not been fully appreciated. Estimates of genetic diversity based on DNA marker analysis could be used as one criteria for determining which plants are targeted for biological control. The success of biological weed control efforts has been limited by the high levels of genetic diversity occurring in target weed specks and the lack of biocontrol agent and target weed compatibilities. DNA-based markers may be used to increase our understanding of these factors and contribute to the success of biological weed control by helping to target the most vulnerable species and provide more realistic expectations of the potential for success given available resources.


2019 ◽  
Vol 38 (3) ◽  
pp. 191-210 ◽  
Author(s):  
Anais Chailleux ◽  
Aurélien Stirnemann ◽  
Jimmy Leyes ◽  
Emilie Deletre

2009 ◽  
Vol 100 (3) ◽  
pp. 367-371 ◽  
Author(s):  
O.L. Kvedaras ◽  
M. An ◽  
Y.S. Choi ◽  
G.M. Gurr

AbstractSilicon (Si) is known to have a role in constitutive plant defence against arthropod pests, and recent work has illustrated involvement in induced plant defences. The present tri-trophic study tested the hypothesis that Si increases natural enemy attraction to pest-infested plants and improves biological control. Cucumber plants treated with potassium silicate (Si+) and untreated control plants (Si−) were maintained in separately vented glasshouse compartments. Y-tube olfactometer studies showed that adult Dicranolaius bellulus were significantly more attracted to Si+ plants upon which Helicoverpa armigera larvae had fed compared with Si−, pest-infested plants. Predators were not significantly more attracted to Si+ plants when comparing uninfested cucumbers. In a field experiment, we placed H. armigera-infested and uninfested Si+ and Si− cucumber plants in a lucerne stand. Removal rates of H. armigera egg baits showed predation was greater for Si+ infested plants than for other treatments. Results suggest that Si applied to plants with a subsequent pest infestation increases the plants' attractiveness to natural enemies; an effect that was reflected in elevated biological control in the field.


2007 ◽  
Vol 97 (3) ◽  
pp. 309-315 ◽  
Author(s):  
D.J. Skirvin ◽  
L. Kravar-Garde ◽  
K. Reynolds ◽  
J. Jones ◽  
A. Mead ◽  
...  

AbstractTwo experiments were done to examine the predation of thrips, and the movement of Orius laevigatus Fieber and Neoseiulus cucumeris (Oudemans) in the presence and absence of two supplemental food sources, pollen and the fungus Trichoderma viride. The presence of pollen led to a 55% reduction in predation of the thrips by N. cucumeris and a 40% reduction in thrips predation by O. laevigatus, in experiments using single predators. The presence of fungus had no significant effect on thrips predation by either of the natural enemy species. Movement of the natural enemies was examined in a multiple predator experiment, and this showed that O. laevigatus was more likely to remain on the plant in the presence of thrips and when supplemental food, either pollen or fungus, was present. For N. cucumeris, there was no association between the presence of thrips and the mite, with the majority of the mites being found on the leaves where pollen was present. Although the single and multiple predator experiments were done at different times, the indications are that the predation rates of the N. cucumeris do not differ greatly between the two experiments, suggesting that there may be a potential interference effect between the mites, which is not present for O. laevigatus. The significance of these results for the use of supplemental food sources in biological control is discussed.


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