Abstract BACKGROUND The pear psylla, Cacopsylla pyri L. (Hemiptera: Psyllidae), is one of the most serious insect pests of pears in Turkey. In recent years, psyllid management has become increasingly difficult because of the development of insecticide resistance and the withdrawal of registered chemicals from the market. In this study, the field efficacy of an emulsifiable concentrate formulation of the entomopathogenic fungus, Metarhizium brunneum Petch strain F52 (Hypocreales: Clavicipitaceae), containing 5.5 × 10 9 conidia mL ‐1 , was evaluated against C. pyri in south‐western Turkey (Antalya) in two consecutive years, 2010 and 2011 . RESULTS The results showed that the F52 product at 100 mL 100 L ‐1 water reduced the number of psyllid eggs and young nymphs (first and second instars), causing up to 79 and 88% mortality, respectively, 7 days after treatment in the first year, and 72 and 82% mortality in the second year. However, it was less active against the older nymphs (third to fifth instars ) and achieved only up to 51% mortality 7 days after treatment in the first year, and 48% mortality in the second year . CONCLUSION The results suggest that the M. brunneum strain F52 product can be used as an alternative to conventional chemicals in controlling C. pyri early in the season. © 2013 Society of Chemical Industry