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VIRUS DISEASES IN RELATION TO COMMERCIAL SEED POTATO PRODUCTION
Author(s) -
WHITEHEAD T.,
CURRIE J. F.,
DAVIES W. MALDWYN
Publication year - 1932
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1932.tb04340.x
Subject(s) - biology , aphid , myzus persicae , potato virus y , crop , population , agronomy , outbreak , horticulture , virus , plant virus , demography , virology , sociology
SUMMARY1 Under a scheme, begun in 1927, and supported by a special grant from the Ministry of Agriculture since 1928, an attempt is being made to test the value of certain localities in North Wales for the production of seed potatoes. 2 Evidence is produced to show that out of fifteen farms originally selected for this purpose, eight have maintained their stocks without increase of virus diseases, three have shown only a slight increase, whilst four have been discarded from the scheme. Replicated yield trials at the College Farm proved that seed mixed from these eleven farms was equal to Scotch “stock” seed, and the value of this Welsh seed was confirmed by trials in a number of Welsh counties in which it was tested against ordinary T.S. Scotch seed. 3 Concurrently with this, a study has been made of the aphid population on the potato crops at these centres, which has led to the following conclusions:a. The absence of increase of virus diseases, and of leaf‐roll in particular, at the more successful centres is not due to the scarcity of aphides, nor to the absence of known vectors of the diseases, such as Myzus persicae. Neither can it be attributed to the non‐infective condition of the aphid vectors present at these centres since representative samples, taken from potato crops, transmitted leaf‐roll to healthy plants under glass. With one exception no transmission occurred with any of the species of aphides when taken from apparently healthy plants in a partially diseased crop. In samples taken from leaf‐roll plants transmission only occurred when they included Myzus persicae.b. The accumulated data suggest that the maintenance of health in potato stocks is influenced not merely by the relative abundance of aphides, but rather by the relation between the date of maximum infestation and the stage of maturity of the foliage. The more successful centres, each year, showed either a delayed maximum infestation and/or the foliage was cut down earlier than at the less successful centres. The relative movement of aphides within the crops at the different centres is certainly of importance, but this is conditioned by many factors which are still under investigation.