PHYTO MEDIZIN Mitteilungen der Deutschen ... - Die DPG

phyll cells of agroinfiltrated leaves to a high extend. Agroinfection did not
lead to an extension of the BMYV host plant spectrum compared to that
previously described in the literature and mainly determined by aphid transmission
of BMYV. Immunological investigation of agroinoculated plant
tissues of N.tabacum cv. ‘Xanthi', N. occidentalis, N. rustica and Chenopodium
capitatum revealed local virus infections in infiltrated mesophyll
cells. However, in these plant species no systemic BMYV infection could be
detected. Moreover in some plant species like N. glutinosa or N. edwardsonii
neither infected plant tissue in agroinfiltrated leaf areas nor a systemic
BMYV spread was detectable. Provided that BMYVfl reaches the phloem
tissue in all tested plant species the method of BMYVfl-agroinfection is a
easy to use procedure to determine local and systemic infectable, local but
not systemic infectable or non-host plants of BMYV.
Epidemiological developments in Potato virus Y
M Verbeek, RAA van der Vlugt, C Cuperus and PGM Piron; Plant Research International
BV, Wageningen
Potato virus Y (PVY) is still responsible for important losses in ware potato
production and seed potato quality. In the Netherlands a control system is in
place that is based on monitoring virus infections in the field and flight data
of a selected group of aphids. From these data foliage destruction dates are
determined in order to prevent tuber infection. Of the three PVY strains,
PVY O (old), PVY C (common) and PVY N (new), PVY N is generally considered
to predominate. However, recent research revealed that PVY O and PVY C
are more present than generally assumed. Based on earlier research the green
peach aphid (Myzus persicae) is considered the most efficient vector of PVY.
As determined from trap data, the population of M. persicae appears to decrease
in the Netherlands, however, problems with (primary) PVY infections
persist. No data are available on the relative efficiency of PVY transmission
of different field isolates (clones) of M. persicae or the role of other aphid
species. To investigate whether efficiencies of different clones of the major
vector of PVY are of the same order or not, potato fields were sampled for M.
persicae and strains of PVY. Transmission experiments were carried out with
the wild and the laboratory clones of M. persicae from potato to Physalis
floridana with two virus strains: PVY N and PVY O . A great variability was
observed between the aphid clones in transmission efficiency. For example:
two clones were not able at all to transmit PVY O , whereas one clone infected
P. floridana with PVY N for 100%. These results indicate a relationship between
the origins of M. persicae and its capability to transmit Potato virus Y.
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