Spatial and temporal variation in the control failure likelihood of the tomato leaf miner, Tuta absoluta

Authors


Correspondence R.N.C. Guedes, Depto de Entomologia,

Universidade Federal de Viçosa, Viçosa, MG

36570-000, Brazil.

Email: guedes@ufv.br

Abstract

Insecticide resistance is frequently associated with field control failure, but such an assessment of its likelihood seldom occurs. This phenomenon is a potential cause of the control failure of the tomato leaf miner Tuta absoluta (Lepidoptera: Gelechiidae); therefore we surveyed insecticide resistance as the control failure likelihood for a duration of 7 years in 20 field populations of this species. The insecticide label rate was used as the discriminating concentration, and the minimum efficacy threshold required for insecticides in Brazil (i.e. 80% efficacy) was the targeted efficacy. The spatial and temporal variations of the control failure likelihood were also assessed, as was the potential influence of land topography for the area-wide pattern observed. Most populations of T. absoluta were susceptible to abamectin, chlorfenapyr and spinosad and not to bifenthrin, triflumuron and teflubenzuron. The indoxacarb susceptibility varied in space and time. Spatial dependence was observed for abamectin and indoxacarb. The control failure likelihood of T. absoluta was higher for bifenthrin, triflumuron and teflubenzuron. A flat topography and the wind direction may favour the spread of the control failure likelihood and should be considered in designing pest management programs for T. absoluta.

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