Citrus Mealybug (Homoptera: Pseudococcidae) on Greenhouse Citrus: Density-dependent Regulation by an Encyrtid Parasite Complex

Summy, Kenneth R.; French, J. Victor; Hart, W. G.

doi:10.1093/jee/79.4.891

Cited by 18 publications

(14 citation statements)

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“…For regulation to occur, the natural enemies must operate in a density‐dependent manner. As with other encrytid parasitoids (Summy, French & Hart 1986), our analysis of the simulation data suggests that A. pseudococci has an over‐compensating density‐dependent response to vine mealybug that is insufficient for economic control. The parasitoid L. abnormis has a density‐dependent action but it is less than compensatory because of a low per capita ‘effective’ search rate (0·004 vs. 0·05).…”

Section: Discussionsupporting

confidence: 52%

Prospective evaluation of the biological control of vine mealybug: refuge effects and climate

Gutiérrez

Daane

Ponti

et al. 2007

Journal of Applied Ecology

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Summary Vine mealybugPlanococcus ficus is an invasive pest of vineyards in many areas of the world. In California, USA, it infests all plant subunits and has a spatial refuge from natural enemies under the bark and on roots. A temporal refuge is created when ants tending the mealybug reduce the efficacy of natural enemies. 2. Biological control of vine mealybug is only partially successful and varies among California grape-growing regions. To improve control and help determine appropriate natural enemies for importation, the effects of weather on mealybug regulation by two parasitoids, Anagyrus pseudococci and Leptomastidea abnormis , and a coccinellid predator, Cryptolaemus montrouzieri , were examined across the ecological regions of California. 3. Weather-driven, physiologically based age-mass structured demographic models of the mealybug and its natural enemies were parameterized using laboratory data and field observations. Temperature was used to define the thermal limits and development rates of each species, and resource supply/demand ratios were used to scale daily per capita growth, fecundity and survivorship rates from maximal values at optimal conditions. 4. The population dynamics of the mealybug and its natural enemies were simulated at 108 locations in California over a 10-year period using observed weather. The simulation data were mapped using a geographical information system (GIS) and analysed using linear multiple regression and marginal analysis. 5. The models predictions indicated that: (i) the parasitoid A. pseudococci has a larger impact on vine mealybug than either L. abnormis or C. montrouzieri ; (ii) mealybug densities will be lowest in the hot desert regions of southern California and highest in the cooler areas of northern California; (iii) mealybug density increases with season length and the size of the combined spatial-temporal refuge; (iv) biological control of mealybug could be achieved by reducing the size of the spatial-temporal refuge. 6. Synthesis and applications. Models, no matter how detailed, will always be incomplete; despite this, the complexity of tri-trophic systems can be modelled and the effects of biotic factors and of weather separated. The predictions of our model coincided well with field observations on vine mealybug, and clearly showed why the biological control will require additional species of natural enemies and/or why the size of the spatial and temporal refuges must be reduced.

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Section: Discussionsupporting

confidence: 52%

Prospective evaluation of the biological control of vine mealybug: refuge effects and climate

Gutiérrez

Daane

Ponti

et al. 2007

Journal of Applied Ecology

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“…This hypothesis is supported by the reports of higher percentage parasitism of P. cirri by L. abnormis than by other parasitoids released as contro ! agents for the mealybug in the glasshouse situation (Tingle, 1985 ;Summy et al, 1986 ; Tingle & Copland, 1988b). There is thus evidence that knowledge of the effects of temperature on the biology of these parasitoids may be valuable in selecting the best candidates as biological control agents for P. citri in a given situation.…”

Section: Longevitymentioning

confidence: 99%

Progeny production and adult longevity of the mealybug parasitoidsAnagyrus pseudococci, Leptomastix dactylopii, andLeptomastidea abnormis [Hym.: Encyrtidae] in relation to temperature

Tingle

Copland

1989

Entomophaga

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Progeny production increased and adult longevity decreased with rising temperature within the range 18 *C to 30 *C for the 3 mealybug parasitoids Anagyrus pseudococci (Girault), Leptomastix dactylopii Howard and Leptomastidea abnormis (Girault). The Weibull distribution gave a good fit to survival curves for the 3 parasitoids and statistical comparison of Weibull b and c parameters at different temperatures allowed changes in the scale and shape of the curves to be detected, In general, ~ lived longer than ~' for all 3 species, except at high temperature.Female L. abnormis attained their maximum progeny production at 24 *C and maintained this level up to 34 *C. They lived longer than the other 2 parasitoid species at 30 *C and showed a type I survival curve throughout the range of temperatures examined. A. pseudococci and L. daetylopii both required high temperatures (30 *C) to attain their maximal progeny production, but were short-lived at this temperature. At 30 *C the survival curves of both ff and ~ A.pseudococci tended towards type II, with a larger proportion of the population dying within the first few days. L. dactylopii lived longest at 26 *C, with ~ showing a type I survival curve at all temperatures and ~' survival curves changing from type I to type II at 30 *C. The implications of these findings for the population dynamics of the different parasitoids are briefly discussed.

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“…The interaction between host and parasitoid is generally regarded as being strongly inßuenced by density dependence (e.g., Summy et al 1986). Such density dependence is not universally detectable in the Þeld which suggests its importance has been overrated (Walter and Zalucki 1999).…”

Section: Fieldmentioning

confidence: 99%

<I>Trichogramma</I> (Hymenoptera: Trichogrammatidae) Ecology in a Tropical Bt Transgenic Cotton Cropping System: Sampling to Improve Seasonal Pest Impact Estimates in the Ord River Irrigation Area, Australia

Davies¹,

Pufke²,

Zalucki³

2009

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Trichogramma Westwood (Hymenoptera: Trichogrammatidae) cause high mortality rates in the potentially resistant pest species, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), and are considered integral to the resistance management plan for Bacillus thuringiensis transgenic cotton, Gossypium hirsutum L., production in the Ord River Irrigation Area (ORIA), Western Australia. Measured as percentage of parasitism, Trichogramma activity seems highly variable over time; yet, it contributes significantly to pest suppression at peak insect pest density. Environmental constraints on Trichogramma survival, especially insecticide applications, may limit their effectiveness. The decision to initiate insecticide applications in ORIA cotton crops is best delayed unless absolutely necessary to avoid disruption of Trichogramma impact on pests. Trichogramma disperse into young crops and display high intrinsic rates of increase effectively stifling Helicoverpa (Hardwick) population increase after initial egg lay during high-density years in the ORIA, and evidence suggests a possible preference for H. armigera host eggs.

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Citrus Mealybug (Homoptera: Pseudococcidae) on Greenhouse Citrus: Density-dependent Regulation by an Encyrtid Parasite Complex

Cited by 18 publications

References 0 publications

Prospective evaluation of the biological control of vine mealybug: refuge effects and climate

Prospective evaluation of the biological control of vine mealybug: refuge effects and climate

Progeny production and adult longevity of the mealybug parasitoidsAnagyrus pseudococci, Leptomastix dactylopii, andLeptomastidea abnormis [Hym.: Encyrtidae] in relation to temperature

<I>Trichogramma</I> (Hymenoptera: Trichogrammatidae) Ecology in a Tropical Bt Transgenic Cotton Cropping System: Sampling to Improve Seasonal Pest Impact Estimates in the Ord River Irrigation Area, Australia

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