Pest Management Science (2019) 75, 45-52

Pablo Bielza, Inmaculada Moreno, Ana Belando, Carolina Grávalos, Josep Izquierdo and Ralf Nauen (2019)
Spiromesifen and spirotetramat resistance in field populations of Bemisia tabaci Gennadius in Spain
Pest Management Science 75 (1), 45-52
Abstract:
BACKGROUND
Spiromesifen and spirotetramat are novel insecticides belonging to the chemical class of tetronic and tetramic acid derivatives. Both compounds have proven very effective against field populations of Bemisia tabaci around the world. However, several growers have recently reported control failures in Spain. Therefore, we studied the resistance level to these insecticides in field populations reporting control failures. In addition, we further selected a spiromesifen-resistant strain to study the mechanisms involved and the cross-resistance pattern.
RESULTS
All the new field populations collected were significantly more resistant to spiromesifen than the susceptible population, confirming the presence of resistance. Several populations showing high levels of resistance to spiromesifen (>10 000-fold), exhibited cross-resistance to spirotetramat, but resistance ratios were much lower (130-fold). The spiromesifen laboratory-selected strain was very resistant to spiromesifen (LC₅₀ > 30 000 mg L^-1) and spirotetramat (LC₅₀ = 368.1 mg L^-1), but lacks any cross-resistance to other insecticides, thus providing options for resistance management. None of the synergists tested significantly restored the susceptibility of B. tabaci to either spiromesifen or spirotetramat.
CONCLUSION
This is the first report of resistance to spiromesifen and spirotetramat in B. tabaci, and such high levels of resistance have not been reported before in any field collected pest. Our results suggest that enhanced detoxification does not critically contribute to resistance to ketoenols in B. tabaci. The obvious lack of a metabolic resistance mechanism either suggests a target-site resistance mechanism or a metabolic mechanism insensitive to the synergists tested.
(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): Ralf Nauen

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.
	Bemisia tabaci	Green pepper/chilli (Capsicum)	Spain (continental)