First outbreak of Aphis gossypii on potatoes in United Kingdom
In August 1993, small breeding colonies of Aphis gossypii were found for the first time on potatoes (cv. Maris Piper) in experimental plots at Auchincruive, Ayrshire, in the west of Scotland, UK. They were found on plants that had been sprayed four times with a mixture of two insecticides (organophosphorus and carbamate). In other countries, A. gossypii is a major pest of cotton and cucurbits, and is also extremely polyphagous attacking a wide range of field and glasshouse crops throughout the world. It reproduces well at temperatures above 30 °C and commonly infests potato crops in North Africa and India, where it has been reported to transmit potato leafroll luteovirus and potato Y potyvirus.
A clone of A. gossypii derived from a single aptera collected from this field was maintained on excised potato leaves. Studies showed that this clone transmitted potato leaf roll luteovirus but was a less efficient vector than other aphid species which occur commonly on potato crops in UK (Myzus persicae, Macrosiphum euphorbiae, Aulacorthum solani).
Attempts were made to rear these aphids on cucumber and chrysanthemum plants. The authors noted that populations of this polyphagous species, collected from cucumber and chrysanthemum in glasshouses in the Netherlands, behave as genetically distinct host races. The clone from Scotland was able to breed only on chrysanthemum. In UK, reports of infestations of A. gossypii on glasshouse chrysanthemum began in late 1975, when it was found that the aphids could not be controlled by pirimicarb. The ability of the aphids found in Scotland to reproduce on insecticide-treated foliage and on chrysanthemum, but not on cucumber, suggests that these aphids originated from a strain associated with glasshouse crops and have adapted to outdoor conditions. Recent reports indicate that A. gossypii is now widespread on potatoes in England in 1996.
Sources
Aphis gossypii: new potato virus vector ? -UK
Foster, G.N.; Woodford, J.A.T. (twoodf@scari.sari.ac.uk)
E-mail message of 1997-01 from PROMED
(promed-plant@usa.healthnet.org)