Determination of some wheat pests and their parasitoids in wheat fields of Central Anatolia Region

The study carried out between April 2001 and June 2003 in Central Anatolia Region aims to determine crop pests, their infestation rate and natural enemies in wheat fields. Among the 16 species of stem sawflies (Cephini) found in wheat fields, Cephus pygmeus (Linnaeus, 1767) and Trachelus tabidus (Fabricius, 1775) are represented with largest population size respectively. Tetramesa tritici (Fitch, 1859), Tetramesa maderea (Walker, 1849) and Tetramesa nr. sp eximia (Giraud, 1863) are determined as gall producers in wheat stems. A total of nine parasitoid species were identified. Of these Chlorocytus breviscapus Graham, 1965 Norbanus obscurus (Masi, 1922) and Collyria coxator (Villers, 1789) are parasitoids of wheat stem sawflies. Merisus splendidus Walker, 1834 and Eurytoma flavimana Boheman, 1836 are identified as parasitoids of gall wasps. Pediobius eubius (Walker) is noted as likely parasitoids of either stem sawflies or gall producers. Hosts of the three retaining parasitoids are not defined with confidence. Two parasitoid species, P. eubius and C. breviscapus are new records for Turkey. The results revealed that rate of wheat stem sawfly infested fields is very high (74.54%), but rate of infested stems is very low (2.78%). Parasitoids are found in 56.3% of the visited wheat fields. This result putatively suggests that the population size of the pest species are essentially controlled by their parasitoids.