Effects of Plant Architecture on the Attack Rate ofLeptomastix dactylopii(Hymenoptera: Encyrtidae), a Parasitoid of the Citrus Mealybug (Homoptera: Pseudococcidae)

Cloyd, Raymond A.; Sadof, Clifford S.

doi:10.1603/0046-225x-29.3.535

Cited by 48 publications

(41 citation statements)

References 36 publications

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“…Previous studies indicate that one L. dactylopii can attack an average of Þve mealybugs out of 10 within a 24-h period (Cloyd and Sadof 2000b). This rate corresponds well with the number of mummies we ob- Means not followed by a common letter are signiÞcantly different (P ϭ 0.05) as determined by a FisherÕs protected LSD mean separation test.…”

Section: Discussionsupporting

confidence: 80%

Effects of Insect Growth Regulators on Citrus Mealybug Parasitoid Leptomastix dactylopii (Hymenoptera: Encyrtidae)

Rothwangl¹,

Cloyd²,

Wiedenmann³

2004

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In this study, we measured the effects of three commonly used insecticides classified as insect growth regulators, on the encyrtid parasitoid Leptomastix dactylopii (Howard) when parasitizing citrus mealybug, Planococcus citri (Risso). Kinoprene, pyriproxyfen, and azadirachtin were evaluated in both petri dish and a cage experiment at label-recommended rates to measure their effects on the mortality, parasitization rate, and sex ratio of L. dactylopii. Insecticides were applied to petri dishes and plants either immediately before, 24 h before, or 48 h before release of the parasitoid. Kinoprene applied 24 h before parasitoid release caused 100% mortality of L. dactylopii in petri dishes within 48 h. Mortality rates for L. dactylopii exposed to azadirachtin and pyriproxyfen did not exceed 5% regardless of release time. There were no release time x insecticide interactions on L. dactylopii parasitization rate. The insecticide alone, however, did significantly affect parasitization rates of L. dactylopii on P. citri; the kinoprene treatment significantly reduced L. dactylopii parasitization rates compared with azadirachtin and pyriproxyfen. In a cage experiment with coleus, Solenostemon scutellaroides (L.) Codd, applications of both pyriproxyfen and kinoprene resulted in fewer P. citri parasitized by L. dactylopii than azadirachtin or the control. The sex ratio was equivalent in the petri dish experiment, whereas in the cage experiment the sex ratio was biased toward males, particularly for the kinoprene treatment. Based on the results from this study, we suggest that kinoprene is not compatible with releases of L. dactylopii to control citrus mealybugs.

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Section: Discussionsupporting

confidence: 80%

Effects of Insect Growth Regulators on Citrus Mealybug Parasitoid Leptomastix dactylopii (Hymenoptera: Encyrtidae)

Rothwangl¹,

Cloyd²,

Wiedenmann³

2004

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“…In univariate analyses of traits, the largest effect was observed for plant size. Aside from its positive association with yield in strawberry (Lacey, 1973), plant size is a key structural component of plant architecture—which amongst other qualities can influence the efficacy of biocontrol in cultivated systems (Cloyd & Sadof, 2000; Udayagiri & Welter, 2000). As a proxy for natural selection, mesoclimatic variation accounted for up to a third of genetic variation in plant size—due, prospectively, to local adaption across the region of study.…”

Section: Discussionmentioning

confidence: 99%

Capturing genetic variation in crop wild relatives: An evolutionary approach

Egan

Muola

Stenberg

2018

Evolutionary Applications

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Crop wild relatives (CWRs) offer novel genetic resources for crop improvement. To assist in the urgent need to collect and conserve CWR germplasm, we advance here the concept of an “evolutionary” approach. Central to this approach is the predictive use of spatial proxies of evolutionary processes (natural selection, gene flow and genetic drift) to locate and capture genetic variation. As a means to help validate this concept, we screened wild‐collected genotypes of woodland strawberry (Fragaria vesca) in a common garden. A quantitative genetic approach was then used to test the ability of two such proxies—mesoclimatic variation (a proxy of natural selection) and landscape isolation and geographic distance between populations (proxies of gene flow potential)—to predict spatial genetic variation in three quantitative traits (plant size, early season flower number and flower frost tolerance). Our results indicated a significant but variable effect of mesoclimatic conditions in structuring genetic variation in the wild, in addition to other undetermined regional scale processes. As a proxy of gene flow potential, landscape isolation was also a likely determinant of observed patterns—as opposed to, and regardless of, geographic distance between populations. We conclude that harnessing proxies of adaptive and nonadaptive evolutionary processes could provide a robust and valuable means to identify genetic variation in CWRs. We thus advocate wider use and development of this approach amongst researchers, breeders and practitioners, to expedite the capture and in situ conservation of genetic resources provided by crop wild relatives.

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“…). Another factor that affects parasitism levels is the density of the respective host (Cloyd and Sadof ; Hancock et al. ).…”

Section: Discussionmentioning

confidence: 99%

Differential susceptibility and suitability of domestic and wild apple species for a florivorous weevil and its parasitoids

Knuff

Obermaier

Mody

2016

J Applied Entomology

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Crop plant domestication can change plant resistance to herbivores leading to differences in pest pressure experienced by crop plants and their wild relatives. To compare resistance to herbivores between domesticated and wild fruit trees, we quantified direct resistance and indirect resistance to a pest insect, the florivorous apple blossom weevil Anthonomus pomorum (Coleoptera: Curculionidae), for the cultivated apple Malus domestica and two wild apple species, the European crab apple M. sylvestris and the exotic M. kirghisorum. We measured weevil infestation and performance (weight, sex ratio), and weevil parasitism by parasitoid wasps for different cultivars of M. domestica and for the two wild apple species. To explain weevil and parasitoid responses to different apple species, we quantified tree characteristics including nitrogen content, size of flower buds, bark roughness, tree size, tree phenology and tree position. We found significant differences in susceptibility to weevil infestation between apple species, with lowest infestation (highest apple resistance) in M. domestica and highest infestation in M. kirghisorum. The suitability of apple species also varied significantly: weevils emerging from M. sylvestris were significantly lighter than those from M. kirghisorum. Parasitism of A. pomorum by different parasitoid species was significantly higher in M. sylvestris than in M. domestica. Infestation, weevil weight and parasitism were positively related to tree characteristics: infestation to bud nitrogen content and bark roughness, weevil size to nitrogen content and bud size, and parasitism to tree height and bud density. Our study revealed marked differences between apple species in susceptibility and suitability for the pest herbivore, but also for antagonistic parasitoids. Whereas direct resistance appeared to be higher in cultivated apple, indirect resistance via parasitoids was apparently higher in wild apple trees. Our findings suggest that wild and cultivated apple trees possess different resistance traits that may be combined to optimize resistance in commercial apple cultivars.

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Effects of Plant Architecture on the Attack Rate ofLeptomastix dactylopii(Hymenoptera: Encyrtidae), a Parasitoid of the Citrus Mealybug (Homoptera: Pseudococcidae)

Cited by 48 publications

References 36 publications

Effects of Insect Growth Regulators on Citrus Mealybug Parasitoid <I>Leptomastix dactylopii</I> (Hymenoptera: Encyrtidae)

Effects of Insect Growth Regulators on Citrus Mealybug Parasitoid <I>Leptomastix dactylopii</I> (Hymenoptera: Encyrtidae)

Capturing genetic variation in crop wild relatives: An evolutionary approach

Differential susceptibility and suitability of domestic and wild apple species for a florivorous weevil and its parasitoids

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