Susceptibility of Catalpa, Chilopsis, and Hybrids to Powdery Mildew and Catalpa Sphinx Larvae

Olsen, Richard T.; Ranney, Thomas G.; Hodges, C. S.

doi:10.21273/hortsci.41.7.1629

Cited by 7 publications

(3 citation statements)

References 3 publications

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“…Moreover, the experiments have been conducted in the absence of reliable spreader plant as a source of natural inoculum to ensure uniform distribution and loads of inoculum. But, a survey of a relatively large number of germplasm materials for the source of resistance and instituting proper safeguards to supply an equal load distribution of an airborne pathogen are considered prerequisite for disease resistance screening (Olsen et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of mulberry germplasm for resistance to powdery mildew in the field and greenhouse

et al. 2010

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Powdery mildew caused by the ascomycete Phyllactinia guttata (syn. P. corylea) is a major foliar disease worldwide of the unique mulberry (Morus spp.) for silkworm feed. Genetic resistance to powdery mildew, the most sustainable and economical strategy for disease control, is still elusive for tropical mulberry. About 147 germplasm sources, representing 18 countries of origin, were screened for resistance to P. guttata in six seasonal fields and greenhouse trials after exposure to natural and artificial inoculum, respectively. In the field, the level of plant responsiveness to disease was assessed from 30 to 62 days after pruning in each season as variations in the disease severity index (DSI), disease incidence (DI%) and area under the disease progress curve (AUDPC). These measures differed significantly among the germplasm. Of 147 germplasm sources, *6.8% had useful resistance (two high and nine moderately resistant) to the powdery mildew pathogen on the basis of DSI. The AUDPC values were 13.5-fold higher in the most susceptible accession-(Philippines) than the least responsive (Vietnam-2). The results of DSI were strongly correlated with the obtained DI values (r = 0.92; P \ 0.01) and AU-DPC (r = 0.89; P \ 0.01). Moreover, field screening results were highly correlated (R 2 = 0.839) with values from the greenhouse evaluation using artificial inoculum. However, the DSI values in field and greenhouse screenings for three sources (Non-nayapati, Nao-khurkul and Tista Valley) varied significantly. A relatively low disease reaction of 09 resources (Vietnam-2, Ankara and 07 others) using different assessment scales after natural and artificial inoculation prove, for the first time, that they have potential in breeding for resistance in tropical mulberry to powdery mildew.

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Section: Introductionmentioning

confidence: 99%

Evaluation of mulberry germplasm for resistance to powdery mildew in the field and greenhouse

et al. 2010

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“…Moreover, this powdery mildew was not detected on C. ovata in the UK (Cook et al, 2006). Also, in a study on susceptibility of Catalpa to powdery mildew (Olsen et al, 2006), C. ovata was resistant to E. elevata.…”

Section: Discussionmentioning

confidence: 93%

Distribution, Incidence and Severity of the Catalpa Powdery Mildew Caused by Erysiphe elevata in North-Eastern Romania

Chinan

Manzu

2018

Not Sci Biol

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Erysiphe elevata is a North American fungus that causes the powdery mildew of Catalpa species. The present study brings new data on the spread of this species in Romania, and given its invasiveness in Europe, the study evaluates the incidence and intensity of the powdery mildew caused to Catalpa bignonioides (Southern catalpa). In 2017, 12 North-Estern Romanian cities where C. bignonioides had been planted in green spaces were investigated. The results have shown that the pathogen is widespread in the North-Estern part of Romania, accompanying the host plant in all of the localities investigated. In addition, the high frequency of the disease, confirms the invasiveness of E. elevata, most affected being the trees that were planted along streets and in public squares. A specimen of E. elevata was sequenced and the BLAST results revealed that it is identical to samples from France and Korea.

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“…No Catalpa tree species or cultivar has demonstrated resistance to Catalpa Sphinx (Olsen et al, 2006), regardless of secondary chemistry. Catalpol sequestration renders several caterpillar species unpalatable (Dyer and Bowers, 1996;Theodoratus and Bowers, 1999;Opitz et al, 2010), and Catalpa Sphinx larvae sequester high concentrations.…”

Section: Discussionmentioning

confidence: 99%

Chemical Defense Across Three Trophic Levels: Catalpa bignonioides, the Caterpillar Ceratomia catalpae, and its Endoparasitoid Cotesia congregata

2011

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Plant secondary chemistry can vary among plant tissues, individuals, and populations, and this variation has population-level consequences for upper trophic levels. In this study, we examined the multi-trophic consequences of variation in iridoid glycosides, which are a component of plant defense against generalist herbivores and also contribute to the unpalatability of sequestering herbivores to both vertebrate and invertebrate predators. Several populations of Catalpa bignonioides were located and examined for the presence of the Catalpa Sphinx, Ceratomia catalpae, a specialist herbivore of Catalpa. We quantified iridoid glycoside content in Catalpa Sphinx caterpillars and in damaged and undamaged C. bignonioides leaves. Overall, leaves of C. bignonioides that were damaged by Catalpa Sphinx caterpillars contained lower concentrations of two major iridoid glycosides, catalpol and catalposide, than leaves of undamaged trees from naturally occurring populations. Catalpa Sphinx caterpillars sequester only catalpol, and increasing catalpol and catalposide concentrations in leaves were associated with increased catalpol sequestration by caterpillars. The parasitoid Cotesia congregata develops successfully inside catalpol-sequestering Catalpa Sphinx caterpillars, and we examined parasitoid larvae for the presence of catalpol. Parasitoid larvae dissected from caterpillars contained catalpol, but at lower concentrations than their host caterpillars. The variation in chemical defense documented here has rarely been documented over multiple trophic levels, but such resolved systems are ideal for examining competing hypotheses about the effects of plant secondary metabolites on higher trophic levels.

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Susceptibility of Catalpa, Chilopsis, and Hybrids to Powdery Mildew and Catalpa Sphinx Larvae

Cited by 7 publications

References 3 publications

Evaluation of mulberry germplasm for resistance to powdery mildew in the field and greenhouse

Evaluation of mulberry germplasm for resistance to powdery mildew in the field and greenhouse

Distribution, Incidence and Severity of the Catalpa Powdery Mildew Caused by Erysiphe elevata in North-Eastern Romania

Chemical Defense Across Three Trophic Levels: Catalpa bignonioides, the Caterpillar Ceratomia catalpae, and its Endoparasitoid Cotesia congregata

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