Population dynamics and biological control

1988 ◽  
Vol 318 (1189) ◽  
pp. 129-169 ◽  
Keyword(s):  
Biological Control ◽  
Density Dependence ◽  
Natural Enemies ◽  
Natural Enemy ◽  
Host Population ◽  
Control Programme ◽  
Life Cycles ◽  
Generalist Predator ◽  
Host Pathogen Interactions ◽  
Host Pathogen

Using simple models for host-parasitoid and host-pathogen interactions, we present a basic framework for examining the outcome of releasing natural enemies against a target pest population in a classical biological control programme. In particular, we examine the conditions for the initial invasion and establishment of a natural enemy species, for the maximum depression of the host population, and for the persistence of the populations in a stable interaction. In these conditions there are close parallels between parasitoids and pathogens. The practice of augmenting an existing natural enemy population by regular mass releases has been widely practised, especially with parasitoids. The conditions for eradication of the pest are very similar in host-parasitoid and host-pathogen models, namely that releases must be greater than the equilibrium production of natural enemies in the absence of releases. Any additional density dependence acting on the host population after the stage attacked by parasitoids can influence the effectiveness of augmentative releases. This is particularly the case with over-compensating density dependence when additional releases can actually lead to an increase in the host population. A theoretical basis for biological control cannot be properly developed simply by considering the dynamics of releasing single natural enemy species. Biological control often involves the interplay among different types of natural enemies affecting the same host population. As a step in the direction of producing more complex, multispecies models, we examine the dynamics of three situations: (1) where the host is attacked by two parasitoid species; (2) by a generalist predator and a specialist parasitoid; or (3) by a parasitoid and a pathogen. The dynamics of these three-species systems can be complex, and with properties not easily foreseen from the separate pairwise interactions. These results caution us against formulating biological control strategies purely in terms of two-species systems. For the main part we examine host-parasitoid interactions with discrete, synchronized generations. These would appear to be less suitable to tropical insects where continuous generations and life cycles of the host and parasitoid of different length are to be expected. We show, however, that cycles (with a period of one host generation) can be obtained from an age-structured simulation model, and that these are promoted by the parasitoids having a life cycle half as long as that of the host. Some implications for biological control are discussed. Finally, we turn briefly to the dynamics of host-parasitoid and host-pathogen interactions where pesticides are also applied, and we discuss the evolution of pesticide resistance within the context of these models.

scholarly journals Methyl Salicylate Fails to Enhance Arthropod Predator Abundance or Predator to Pest Ratios in Cotton

2021 ◽  
Author(s):  
Steven E Naranjo ◽  
James R Hagler ◽  
John A Byers
Keyword(s):  
Biological Control ◽  
Natural Enemies ◽  
Natural Enemy ◽  
Methyl Salicylate ◽  
Production Systems ◽  
Control Function ◽  
Conservation Biological Control ◽  
Cotton Production ◽  
Control Activity ◽  
Synthetic Chemicals

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.

An Investigation of the Possibilities of Biological Control ofMelittomma insulareFairm. (Coleoptera, Lymexylonidae), a serious Pest of Coconut in the Seychelles

1956 ◽  
Vol 47 (4) ◽  
pp. 685-702 ◽  
Author(s):  
F. J. Simmonds
Keyword(s):  
Biological Control ◽  
Natural Enemies ◽  
Natural Enemy

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.

Silicon enhances natural enemy attraction and biological control through induced plant defences

2009 ◽  
Vol 100 (3) ◽  
pp. 367-371 ◽  
Author(s):  
O.L. Kvedaras ◽  
M. An ◽  
Y.S. Choi ◽  
G.M. Gurr
Keyword(s):  
Biological Control ◽  
Field Experiment ◽  
Recent Work ◽  
Natural Enemies ◽  
Natural Enemy ◽  
Untreated Control ◽  
Plant Defence ◽  
Plant Defences ◽  
Pest Infestation ◽  
Arthropod Pests

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.

Supplemental food affects thrips predation and movement of Orius laevigatus (Hemiptera: Anthocoridae) and Neoseiulus cucumeris (Acari: Phytoseiidae)

2007 ◽  
Vol 97 (3) ◽  
pp. 309-315 ◽  
Author(s):  
D.J. Skirvin ◽  
L. Kravar-Garde ◽  
K. Reynolds ◽  
J. Jones ◽  
A. Mead ◽  
...  
Keyword(s):  
Biological Control ◽  
Natural Enemies ◽  
Natural Enemy ◽  
Trichoderma Viride ◽  
Food Sources ◽  
Neoseiulus Cucumeris ◽  
Orius Laevigatus ◽  
Supplemental Food ◽  
Species Movement ◽  
Predation Rates

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.

Classical biological control of an invasive forest pest: a world perspective of the management ofSirex noctiliousing the parasitoidIbalia leucospoides(Hymenoptera: Ibaliidae)

2014 ◽  
Vol 105 (1) ◽  
pp. 1-12 ◽  
Author(s):  
D. Fischbein ◽  
J.C. Corley
Keyword(s):  
Biological Control ◽  
Natural Enemy ◽  
Regional Scale ◽  
Classical Biological Control ◽  
Host Population ◽  
Limiting Factor ◽  
Sirex Noctilio ◽  
Affect Control ◽  
Control Programmes ◽  
History Of

AbstractClassical biological control is a key method for managing populations of pests in long-lived crops such as plantation forestry. The execution of biological control programmes in general, as the evaluation of potential natural enemies remains, to a large extent, an empirical endeavour. Thus, characterizing specific cases to determine patterns that may lead to more accurate predictions of success is an important goal of the much applied ecological research. We review the history of introduction, ecology and behaviour of the parasitoidIbalia leucospoides. The species is a natural enemy ofSirex noctilio, one of the most important pests of pine afforestation worldwide. We use an invasion ecology perspective given the analogy between the main stages involved in classical biological control and the biological invasion processes. We conclude that success in the establishment, a common reason of failure in biocontrol, is not a limiting factor of success byI. leucospoides. A mismatch between the spread capacity of the parasitoid and that of its host could nevertheless affect control at a regional scale. In addition, we suggest that given its known life history traits, this natural enemy may be a better regulator than suppressor of the host population. Moreover, spatial and temporal refuges of the host population that may favour the local persistence of the interaction probably reduce the degree to whichS. noctiliopopulation is suppressed by the parasitoid. We emphasize the fact that some of the biological attributes that promote establishment may negatively affect suppression levels achieved. Studies on established non-native pest–parasitoid interactions may contribute to defining selection criteria for classical biological control which may prove especially useful in integrated pest management IPM programmes of invasive forest insects.

scholarly journals Landscape composition mediates suppression of major pests by natural enemies in conventional cruciferous vegetables

2021 ◽  
Author(s):  
Jie Zhang ◽  
Shijun You ◽  
Dongsheng Niu ◽  
Karla Giovana Gavilanez Guaman ◽  
Ao Wang ◽  
...  
Keyword(s):  
Biological Control ◽  
Natural Enemies ◽  
Natural Enemy ◽  
Positive Impact ◽  
Spatial Scales ◽  
Habitat Diversity ◽  
Landscape Composition ◽  
Dispersal Ability ◽  
Cruciferous Vegetables ◽  
Natural Habitats

ABSTRACTBackgroundConservation biological control provides an environment-friendly approach to improve the efficacy of natural enemies. Although numerous studies have demonstrated the potential of semi-natural habitats in promoting biological control in organic or unsprayed agroecosystems, few studies were conducted in conventional agricultural fields. In this study, we investigated the effects of landscape composition on the major pests of cruciferous vegetables and on the assemblages of their natural enemies in southeastern China.ResultsHabitat diversity, particularly increasing grassland proportion in the landscape, had a positive impact in controlling both small-sized pests (aphids, leaf miners, thrips and flea beetles) and Plutella xylostella. This increasing proportion also promoted greater abundance and diversity of canopy-dwelling predators, more forests supported a higher diversity of airborne enemies (parasitoids and canopy-dwelling predators) as well as a higher abundance of ground-dwelling predators. A general increase in habitat diversity was beneficial to parasitoids and ground-dwelling predators. Additionally, the proportion of forest, grassland, and non-cruciferous vegetable area, as well as habitat diversity, affected the compositions of natural enemy communities. Moreover, inconsistent effects of non-cruciferous and grassland habitats were found between sampling regions for small-sized pests and canopy-dwelling predators. Moreover, the scale at which pests and natural enemies’ abundance and richness responded most to landscape composition varied with their feeding range and dispersal ability.ConclusionOur study provides evidence that increasing the amount of semi-natural habitats and habitat diversity can result in lower pest and higher natural enemy abundance in conventional cruciferous agroecosystems. Regional conditions and spatial scales also should be considered in designing the agricultural landscape mosaic.

scholarly journals Collections of Microctonus aethiopoides Loan (Hymenoptera Braconidae) from Ireland

2006 ◽  
Vol 59 ◽  
pp. 290-296 ◽  
Author(s):  
M.R. McNeill ◽  
J.R. Proffitt ◽  
P.J. Gerard ◽  
S.L. Goldson
Keyword(s):  
Biological Control ◽  
New Zealand ◽  
Natural Enemy ◽  
Control Programme ◽  
Sitona Lepidus ◽  
Microctonus Aethiopoides

The biological control programme against Sitona lepidus (Gyllenhal) (Coleoptera Braconidae) commenced in 1998 with the first parasitised weevils imported into New Zealand quarantine in 2000 Extensive collections in Europe confirmed that the solitary endoparasitoid Microctonus aethiopoides Loan (Hymenoptera Braconidae) was the principal natural enemy of adult S lepidus With one exception all M aethiopoides reared from S lepidus collected in Europe have been arrhenotokous All M aethiopoides collected from Ireland are thelytokous which obviates the risk of hybridisation with an arrhenotokous Moroccan strain already established in New Zealand Levels of parasitism in S lepidus fieldcollected from Ireland were low (lt;8) and overall averaged 07 Rates of parasitism of S lepidus in New Zealand quarantine have averaged 25 but ranged from 0 to 95 Aspects relating to the rearing and management of Irish M aethiopoides are discussed including possible reasons for low rates of parasitism in quarantine

scholarly journals Balancing Disturbance and Conservation in Agroecosystems to Improve Biological Control

2020 ◽  
Vol 65 (1) ◽  
pp. 81-100 ◽  
Author(s):  
John F. Tooker ◽  
Matthew E. O'Neal ◽  
Cesar Rodriguez-Saona
Keyword(s):  
Biological Control ◽  
Natural Enemies ◽  
Natural Enemy ◽  
Crop Production ◽  
Agricultural Intensification ◽  
Conservation Practices ◽  
Insect Outbreaks ◽  
Top Down ◽  
Crop Fields ◽  
Pest Outbreaks

Disturbances associated with agricultural intensification reduce our ability to achieve sustainable crop production. These disturbances stem from crop-management tactics and can leave crop fields more vulnerable to insect outbreaks, in part because natural-enemy communities often tend to be more susceptible to disturbance than herbivorous pests. Recent research has explored practices that conserve natural-enemy communities and reduce pest outbreaks, revealing that different components of agroecosystems can influence natural-enemy populations. In this review, we consider a range of disturbances that influence pest control provided by natural enemies and how conservation practices can mitigate or counteract disturbance. We use four case studies to illustrate how conservation and disturbance mitigation increase the potential for biological control and provide co-benefits for the broader agroecosystem. To facilitate the adoption of conservation practices that improve top-down control across significant areas of the landscape, these practices will need to provide multifunctional benefits, but should be implemented with natural enemies explicitly in mind.

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