Volume 6, Issue 4 p. 295-309

The impact of insecticide resistance in the currant-lettuce aphid, Nasonovia ribisnigri, on pest management in lettuce

N. B. Kift

N. B. Kift

Warwick HRI, University of Warwick, Wellesbourne, Warwick CV35 9EF, U.K. and

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A. Mead

Corresponding Author

A. Mead

Warwick HRI, University of Warwick, Wellesbourne, Warwick CV35 9EF, U.K. and

Andrew Mead. Tel: +44 (0)24 7657 5020; fax: +44 (0)24 7657 4500; e-mail: [email protected]Search for more papers by this author
K. Reynolds

K. Reynolds

Warwick HRI, University of Warwick, Wellesbourne, Warwick CV35 9EF, U.K. and

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S. Sime

S. Sime

Warwick HRI, University of Warwick, Wellesbourne, Warwick CV35 9EF, U.K. and

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M. D. Barber

M. D. Barber

Division of Plant and Invertebrate Ecology, Rothamsted Research, Harpenden, Herts AL5 2JQ, U.K.

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I. Denholm

I. Denholm

Division of Plant and Invertebrate Ecology, Rothamsted Research, Harpenden, Herts AL5 2JQ, U.K.

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G. M. Tatchell

G. M. Tatchell

Warwick HRI, University of Warwick, Wellesbourne, Warwick CV35 9EF, U.K. and

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First published: 27 October 2004
Citations: 20

Abstract

Abstract  1 This paper reports on experiments to determine how two different insecticide resistance phenotypes in the aphid Nasonovia ribisnigri (Mosley), which is a major pest of lettuce, change its susceptibility to pyrethroid insecticides and the carbamate pirimicarb.

2 A novel statistical approach determined how the effectiveness of different insecticides was changed by the two resistance phenotypes. This compared the between-plant distribution of aphid numbers, as opposed to the mean number of aphids per plant.

3 Results from field cage experiments showed that the effect of the resistances differed. Pyrethroid resistance resulted in lower mortality immediately after application of pyrethroids, whereas resistance to pirimicarb shortened the time over which the chemical was effective.

4 The results of laboratory bioassays suggested that these two resistances were not found together in N. ribisnigri. However, the results reported here contradict this assertion.

5 Experiments with insecticide residues showed that reproduction of resistant N. ribisnigri was greater than that of susceptible N. ribisnigri on plants with ageing insecticide residues, even in circumstances where mortality of resistant and susceptible clones of N. ribisnigri were similar.

6 If more than a few aphids are found on a plant then a whole consignment can be rejected for processing. The results reported here suggest that the effect of both insecticide resistances in N. ribsinigri will be to increase the proportion of lettuce heads with an unacceptable number of aphids on them, leading to increased rejection of plants for processing.