Comparison of AC Electronic Monitoring and Field Data for Estimating Tolerance to &lt;I&gt;Empoasca kraemeri&lt;/I&gt; (Homoptera: Cicadellidae) in Common Bean Genotypes

Serrano, Miguel S.; Backus, Elaine A.; Cardona, César

doi:10.1603/0022-0493-93.6.1796

Cited by 29 publications

(32 citation statements)

References 22 publications

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“…The Þndings described above strongly suggest that potato leafhopper resistance is not directly related to hopperburn resistance. We chose to test this hypothesis, as well as to more completely analyze the data, using PCA methods outlined in more detail in Serrano et al (2000). The hypothesis was supported by an initial PCA of all 10 variables, which loaded yellowing and stem growth reduction to widely different factors, and in directly opposite sign of those for leafhopper-affecting variables.…”

Section: Figmentioning

confidence: 99%

“…We followed the general formula described in more detail in Serrano et al (2000), which in turn was developed from a yield-based resistance index formulated by bean breeders at Centro Internacional de Agricultura Tropical (CIAT), Cali, Colombia. Our only modiÞcation (compared with Serrano et al 2000) is that we weighted each PCA factor score for importance in the overall index. Thus, Þrst each genotypeÕs mean score was multiplied by the percentage of the experimentÕs overall variance explained by that factor.…”

Section: Figmentioning

confidence: 99%

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Glandular-Haired Alfalfa Resistance to Potato Leafhopper (Homoptera: Cicadellidae) and Hopperburn: Development of Resistance Indices

Shockley

Backus

Ellersieck

et al. 2002

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Eight proprietary genotypes of glandular-haired alfalfa, Medicago sativa L., supplied by two different companies, were compared for the degree and types of resistance to the potato leafhopper, Ernpoasca fabae (Harris), and hopperburn. A tube cage no-choice bioassay was developed to test leafhopper mortality, feeding, settling preferences, severity of hopperburn symptoms (in this case, defined as both yellowing and stem growth reduction), and trichome density and type on feeding sites. Leafhopper mortality was both strongly and significantly associated with feeding and leaf trichome density; decreased hopperburn symptom severity was weakly, although significantly, associated with increased mortality. To quantify hopperburn in terms of both yellowing and stem growth reduction, we developed a ranking system that reduces overall hopperburn expression to a single number that considers the varying responses to both types of symptoms. Great variability in leafhopper settling, leafhopper mortality, and stem glandular trichome density was detected among alfalfa genotypes, suggesting that genotypic differences may be based on the concentration and/or chemical constituency of the trichome exudates. We postulate that, among variably resistant genotypes of glandular-haired alfalfa, differences among leafhopper responses and hopperburn severity are linked to forced movement from the stems to the leaves as refuge feeding sites. Principal component analysis was performed to reduce the 10 variables down to five biologically significant factors. Scores for these factors were then used to develop resistance indices for potato leafhopper resistance, hopperburn resistance, and an overall glandular-haired alfalfa resistance index.

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Section: Figmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

Glandular-Haired Alfalfa Resistance to Potato Leafhopper (Homoptera: Cicadellidae) and Hopperburn: Development of Resistance Indices

Shockley

Backus

Ellersieck

et al. 2002

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“…Both of these types of antixenosis and tolerance, respectively, already have been demonstrated in common bean varieties exposed to Empoasca leafhoppers (Serrano et al 2000), and also seem likely in alfalfa.…”

Section: Discussionmentioning

confidence: 68%

“…We suspect that two other mechanisms of reduced hopperburn are probably also occurring to a variable extent in all resistant genotypes: (1) additional, contact chemical compounds in the plant may prevent feeding by the leafhopper, or cause the insect to alter its feeding to a less hopperburn-causing type (Serrano et al 2000), and/or (2) physiological tolerance mechanisms of the plant may reduce the plant response (a "saliva-enhanced wound response" Backus 1995b, Ecale Zhou andBackus 1999]) that initiates hopperburn. Both of these types of antixenosis and tolerance, respectively, already have been demonstrated in common bean varieties exposed to Empoasca leafhoppers (Serrano et al 2000), and also seem likely in alfalfa.…”

Section: Discussionmentioning

confidence: 99%

Repellency to the Potato Leafhopper (Homoptera: Cicadellidae) by Erect Glandular Trichomes on Alfalfa

Shockley

Backus

2002

Environ Entomol

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We sought to gain insights into the mechanism of resistance of glandular-haired alfalfa to the potato leafhopper, by testing the trichomes of proprietary genotypes for chemical versus morphological differences. Two-choice, noncontact tests were conducted using four glandular-haired and one glabrous genotype of alfalfa, representing a spectrum of resistance, to determine whether adult female leafhoppers could detect and be repelled by putative volatiles released from the trichomes. Settling patterns roughly agreed with the degree of resistance reported by industry scientists who provided the plants. Repellency was strong for the most resistant genotypes, and absent with the most susceptible genotype. The remaining, intermediate-to-low-resistance genotypes exhibited variable repellency. A no-choice, plant-contact preference test showed no signiÞcant differences in settling among stems left intact or denuded, neither within nor among all genotypes. In all cases, adult leafhoppers settled on glandular-haired alfalfa if given no alternative. Environmental scanning electron microscopy of erect, glandular trichomes of eight proprietary genotypes (including the four used above) showed no obvious morphological differences among genotypes, or between stems and leaves within each genotype, although morphological comparisons were not quantiÞed due to the fragility of the specimens. Taken together, our results suggest that volatile compounds contribute to variable levels of repellency to potato leafhoppers by glandular-haired alfalfa, but that such compounds cannot strongly prevent feeding at all costs.

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“…Feeding by an insect like M. scutellaris is very difficult to determine and quantify because stylet punctures can be microscopic and feeding is indistinguishable from probing unless sophisticated electronic monitoring is used (Serrano, Backus, and Cardona 2000). Therefore, our primary metric for determining host suitability was insect survival with nymph emergence, survival, and development providing secondary measures.…”

Section: Quarantine Host Range Testsmentioning

confidence: 99%

Host specificity assessment and potential impact ofMegamelus scutellaris(Hemiptera: Delphacidae) on waterhyacinthEichhornia crassipes(Pontederiales: Pontederiaceae)

Tipping

Center

Sosa³

et al. 2011

Biocontrol Science and Technology

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The delphacid Megamelus scutellaris Berg was evaluated for host specificity and potential impact as part of a biological control program targeting Eichhornia. crassipes. Survival and development of adults and nymphs were used as metrics with no-choice, two-choice, nymph transfer, and sustainability tests conducted under quarantine conditions. A total of 69 plant species were tested including 12 from the Pontederiaceae (including E. crassipes). Additionally, 27 native and 5 exotic associated wetland species and 11 economic species were tested. Megamelus scutellaris exhibited a high level of oviposition and developmental fidelity to E. crassipes by failing to sustain populations on any non-target test plant past the F 1 generation. Nymph transfer tests which simulated potential spill-over events found that survival was virtually non-existent on associated wetland plants, regardless of taxonomic relatedness, including on Pontederia cordata, an important and widespread native species. Eichhornia crassipes plants exposed to two consecutive generations of feeding produced 66.9% less biomass and 73.4% fewer leaves than those in the controls. We conclude that Megamelus scutellaris is safe to release on E. crassipes in the United States.

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Comparison of AC Electronic Monitoring and Field Data for Estimating Tolerance to <I>Empoasca kraemeri</I> (Homoptera: Cicadellidae) in Common Bean Genotypes

Cited by 29 publications

References 22 publications

Glandular-Haired Alfalfa Resistance to Potato Leafhopper (Homoptera: Cicadellidae) and Hopperburn: Development of Resistance Indices

Glandular-Haired Alfalfa Resistance to Potato Leafhopper (Homoptera: Cicadellidae) and Hopperburn: Development of Resistance Indices

Repellency to the Potato Leafhopper (Homoptera: Cicadellidae) by Erect Glandular Trichomes on Alfalfa

Host specificity assessment and potential impact ofMegamelus scutellaris(Hemiptera: Delphacidae) on waterhyacinthEichhornia crassipes(Pontederiales: Pontederiaceae)

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