Articles
Development of screening assays and diagnostic techniques to assess resistance to willow carrot aphid (Cavariella aegopodii) and carrot red leaf virus (CtRLV)
Article number
1393_12
Pages
91 – 98
Language
English
Abstract
The willow carrot aphid (Cavariella aegopodii, Scopoli, 1973) is a major pest of carrot, parsnip and celery crops, as well as many wild apiaceous hosts.
Overwintering on willow, young aphids migrate to apiaceous plants including crop hosts in May where they cause significant damage including leaf discolouration and distortion.
Of greater importance to carrot growers is the transmission of a range of viruses, most notably the carrot red leaf virus (CtRLV), part of the carrot motley dwarf (CMD) complex.
CtRLV symptoms include reddening and yellowing of leaves and stunting, resulting in severe crop losses.
Chemical control is limited, so new strategies for pest management and sources of host-plant resistance are required.
This research set out to develop specific screening methods and diagnostic techniques to identify novel sources of resistance for future disease management.
A field trial of 10 carrot accessions, including landrace and elite varieties representing broad carrot phenotypic and genotypic variation, was screened for resistance to C. aegopodii. Total aphid numbers following initial migration were monitored alongside foliage density.
A range of aphid numbers was observed across the accessions, suggesting susceptible and resistant genotypes are present within the cultivars screened.
Controlled environment assays testing the same carrot accessions also supported the identification of susceptible and resistant cultivars.
To assess the CtRLV levels in leaf samples collected from the field trial we have developed molecular diagnostic techniques, include an RT-LAMP assay, and we are currently determining differences in virus load between the carrot accessions.
These studies have identified a range of resistant and susceptible carrot lines under controlled environment and field conditions and have developed novel diagnostics techniques for assessing virus load.
Overwintering on willow, young aphids migrate to apiaceous plants including crop hosts in May where they cause significant damage including leaf discolouration and distortion.
Of greater importance to carrot growers is the transmission of a range of viruses, most notably the carrot red leaf virus (CtRLV), part of the carrot motley dwarf (CMD) complex.
CtRLV symptoms include reddening and yellowing of leaves and stunting, resulting in severe crop losses.
Chemical control is limited, so new strategies for pest management and sources of host-plant resistance are required.
This research set out to develop specific screening methods and diagnostic techniques to identify novel sources of resistance for future disease management.
A field trial of 10 carrot accessions, including landrace and elite varieties representing broad carrot phenotypic and genotypic variation, was screened for resistance to C. aegopodii. Total aphid numbers following initial migration were monitored alongside foliage density.
A range of aphid numbers was observed across the accessions, suggesting susceptible and resistant genotypes are present within the cultivars screened.
Controlled environment assays testing the same carrot accessions also supported the identification of susceptible and resistant cultivars.
To assess the CtRLV levels in leaf samples collected from the field trial we have developed molecular diagnostic techniques, include an RT-LAMP assay, and we are currently determining differences in virus load between the carrot accessions.
These studies have identified a range of resistant and susceptible carrot lines under controlled environment and field conditions and have developed novel diagnostics techniques for assessing virus load.
Authors
L.H.K. Chappell, R.H. Collier, C.J. Allender, G.C. Barker, G.R. Teakle
Keywords
Daucus carota, willow carrot aphid, Cavariella aegopodii, carrot red leaf virus, molecular diagnostics, RT-LAMP
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