Insect pests determined in fresh onion fields in Izmir province [İzmir ilinde taze sogan tarlalarínda saptanan böcek türleri]

In this study, insect pests of fresh onion cultivated areas of Izmir province have been determined. For this purpose, 155 onion fields have been observed in Bayíndír, Çeşme, Kemalpaşa, Menemen, Tire and Torbalí districts in 2006, periodically. In the following years, 164 onion fields have been observed in Bayíndír, Bornova, Menemen and Tire in 2007-2008. Six families, seven species and four genera from Hemiptera, seven species from Thripidae, two species from Phlaeothripidae and four species from Aeolothripidae of Thysanoptera have been found throughout the study. Two families, six species from Coleoptera and one species from Neuroptera order have been determined. In addition, one species and the species from 10 families of Diptera (Chloropidae, Chironomidae, Drosophilidae, Empididae, Mycetophilidae, Muscidae, Phoridae, Psichodidae, Sepsidaea, Sciaridae) have been found. As a result of study, Thrips tabaci Lindeman (Thysanoptera: Thripidae) and Bactericera tremblayi Wagner (Hemiptera: Triozidae) have been considered as the key pest and the second major pest, respectively. The most important species among dipterans has been determined as Delia platura Meigen of Anthomyiidae. Aeolothrips intermedius Bagnall (Thysanoptera: Aeolothripidae) has been determined as the most abundant natural enemy. Orius spp. (Hemiptera: Anthocoridae), Nabis spp. (Hemiptera: Nabidae), Coccinella septempunctata L. (Coleoptera: Coccinellidae), Chrysoperla carnea Steph. (Neuroptera: Chrysopidae) were determined rarely as natural enemies. In the study abundance of the natural enemies were found rarely because of intensive and non specific uses of pesticides