The effect of insecticides on the spread of potato leaf roll virus in seed potato fields at Pukekohe

Abstract

In recent years potato seed crops at Pukekohe have shown high levels of leaf roll virus infection, in spite of the use of insecticides. Laboratory and field tests have shown that although insecticides control aphid populations, they do not kill viruliferous insects quickly enough to prevent transmission of leaf roll to potato. High levels of leaf roll were seen in plots of potatoes that had emerged in a peak of aphid flight activity in the second half of November 1969, whereas plots emerging later were relatively free of virus. The evidence suggests that most of the virus seen in seed potato fields is brought there by viruliferous aphids migrating from infected crops in the neighbourhood. Isolation of seed fields from the Pukekohe district is advocated.

Potato leafroll virus (PLRV): its transmission and control

“…In such a situation insecticides may strongly reduce the virus spread from plant to plant within a crop but they are much less effective in protecting crops against PLRVcarrying aphids arriving from other crops (Bacon et al 1976;Peters 1987). Such aphids can survive the uptake of insecticides long enough to cause infection in the plant on which they feed (Till 1971;Woodford et al 1994). For this reason, the value of cultivar resistance to PLRV to protect the potato plants until the insecticide is applied, is evident.…”

Insecticidal reduction of Potato leafroll virus transmission by Myzus persicae

“…Consequently, of the several measures used to control the spread of PLRV in the field, insecticidal management of aphid vectors is generally considered effective, presumably because the insect is killed before the latent period is completed (Schepers, 1987;Syller, 1996;Perring et al, 1999). Limiting the spread of circulatively transmitted plant viruses within a field often has been accomplished by insecticidal control of their aphid vectors (Burt et al, 1960;Powell & Mondor, 1973;Woodford & Mann, 1992;Gourmet et al, 1994Gourmet et al, , 1996Perring et al, 1999), but in some cases insecticides have failed to limit virus spread even when aphid control was effective (Till, 1971;Bacon et al, 1976;Woodford et al, 1983;Syller, 1996).…”

Aphids species on potato crops in Canterbury

“…Nine of these are PLRV vectors. In New Zealand the aphid fauna of potato crops has been dominated by three species, the green peach aphid Myzus persicae (Sulzer), the foxglove aphid Aulacorthum solani (Kaltenbach), and the potato aphid Macrosiphum euphorbiae (Thomas) (Cottier 1931;Watts 1953;Close 1965;Till 1971;Miln 1978;Webby 1988). All are vectors of PLRV and other potato viruses.…”

“…All are vectors of PLRV and other potato viruses. The relative abundance of these species has varied between studies with numbers of the green peach aphid increasing and the foxglove aphid decreasing in relation to other species in relatively recent studies (Till 1971;Webby 1988).…”