Pest Management Science (2010) 66, 839-846

Sarfraz Ali Shad, Ali H. Sayyed and Mushtaq A. Saleem (2010)
Cross-resistance, mode of inheritance and stability of resistance to emamectin in Spodoptera litura (Lepidoptera: Noctuidae)
Pest Management Science 66 (8), 839-846
Abstract: BACKGROUND: Spodoptera litura (F.) is a cosmopolitan pest that has developed resistance to several insecticides. The aim of the present study was to establish whether an emamectin-selected (Ema-SEL) population could render cross-resistance to other insecticides, and to investigate the genetics of resistance.
RESULTS: Bioassays at G₁ gave resistance ratios (RRs) of 80-, 2980-, 3050- and 2800-fold for emamectin, abamectin, indoxacarb and acetamiprid, respectively, compared with a laboratory susceptible population Lab-PK. After three rounds of selection, resistance to emamectin in Ema-SEL increased significantly, with RRs of 730-fold and 13-fold compared with the Lab-PK and unselected (UNSEL) population respectively. Further studies revealed that three generations were required for a tenfold increase in resistance to emamectin. Resistance to abamectin, indoxacarb, acetamiprid and emamectin in UNSEL declined significantly compared with the field population at G₁. Furthermore, selection with emamectin reduced resistance to abamectin, indoxacarb and acetamiprid on a par with UNSEL. Crosses between Ema-SEL and Lab-PK indicated autosomal and incomplete dominance of resistance. A direct test of a monogenic model and Land's method suggested that resistance to emamectin was controlled by more than one locus.
CONCLUSION: Instability of resistance and lack of cross-resistance to other insecticides suggest that insecticides with different modes of action should be recommended to reduce emamectin selection pressure.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Ali H. Sayyed

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Spodoptera litura