Accepted Article Spiromesifen and spirotetramat resistance in field populations of Bemisia tabaci Gennadius in Spain Running title: Ketoenol resistance in Bemisia tabaci Pablo Bielza, a, * Inmaculada Moreno, a Ana Belando, a Carolina Grávalos, a Josep Izquierdo b and Ralf Nauen c a Departamento de Producción Vegetal, Universidad Politécnica de Cartagena, Paseo Alfonso XIII 48, 30203 Cartagena, Spain b Bayer Crop Science S.L, Development Iberia, C. Charles Robert Darwin 13, 46980 Paterna, Spain c Bayer AG, Crop Science Division, R&D, Pest Control, 40789 Monheim, Germany * Correspondence to: Pablo Bielza, Dpto. Producción Vegetal, Universidad Politécnica de Cartagena, Pº Alfonso XIII 48, 30203-Cartagena, Spain. E-mail: pablo.bielza@upct.es 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. This article is protected by copyright. All rights reserved. This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1002/ps.5144