Huseyin CETIN * , Esref DEMIR, Serap KOCAOGLU, Bulent KAYA Akdeniz University, Faculty of Arts and Sciences, Department of Biology, 07058 Antalya-TURKEY * Corresponding author: hcetin@akdeniz.edu.tr Insecticidal Activity of Some Synthetic Pyrethroids with Different Rates of Piperonyl Butoxide (PBO) Combinations on Drosophila melanogaster (Diptera: Drosophilidae) Abstract Piperonyl Butoxide (PBO) is an insecticide synergist inhibiting the detoxification enzymes within insect tissues. PBO itself is not an insecticide, it is added to increase the potential effect of insecticides and it has an important role in reducing resistance levels and insecticide application rates. In this study, Drosophila melanogaster laboratory populations were exposed to the synthetic pyrethroids (Cypermethrin, Cyphenothrin, Deltamethrin and Permethrin) either alone or in combinations with different rates of piperonyl butoxide (PBO). Our results showed that the mixture of pyrethroids and PBO caused an increase in the mortality and knock down values and decreased knock down times more than pyrethroid alone, on D. melanogaster in a dose dependent manner up to a certain dosage. The results suggest that PBO ratios in insecticide formulations should be determined with efficiency tests according to pest species, active materials and resistance ratios. Keywords: Drosophila melanogaster, insecticidal activity, piperonyl butoxide (PBO), synthetic pyrethroids. Farklý Oranlarda PBO ile Karýþtýrýlan Bazý Sentetik Pyretroitlerin Drosophila melanogaster Üzerindeki Ýnsektisidal Aktivitesi Özet Bir insektisit sinerjisti olan Piperonil Butoksit (PBO) böcek dokularý içinde detoksifikasyon enzimlerini inhibe etmektedir. PBO kendi baþýna bir insektisit deðildir, insektisit uygulama oranlarýnýn ve direnç seviyelerinin azalmasýnda önemli bir role sahiptir ve insektisitlerin potansiyel etkilerinin artmasýna katký saðlar. Bu çalýþmada, Drosophila melanogaster'in laboratuvar populasyonlarý sentetik piretroitlerin (Cypermethrin, Cyphenothrin, Deltamethrin ve Permethrin) ya tek baþlarýna ya da farklý PBO oranlarý ile kombinasyonlarýyla maruz býrakýlmýþtýr. Sonuçlarýmýz piretroit ve PBO karýþýmýnýn, piretroitlere göre düþme zamanlarýný azalttýðýný, öldürücü ve düþürücü oranlarda bir artýþa sebep olduðunu ve bu deðerlerin D. melanogaster'de belirlenen dozlara baðlý olarak deðiþtiðini göstermiþtir. Bizim sonuçlarýmýza göre; insektisit formülasyonlarýndaki PBO oranlarý zararlý tür çeþidi, aktif içerik ve direnç oranlarýna göre, etkinlik testleri ile belirlenmelidir. Anahtar Kelimeler: Drosophila melanogaster, insektisidal aktivite, piperonil butoksit (PBO), sentetik piretroit. Cetin H, Demir E, Kocaoglu S, Kaya B (2010) Insecticidal Activity of Some Synthetic Pyrethroids with Different Rates of Piperonyl Butoxide (PBO) Combinations on Drosophila melanogaster (Diptera: Drosophilidae). Ekoloji 19, 75, 27-32. No: 75, 2010 27 Ekoloji 19, 75, 27-32 (2010) doi: 10.5053/ekoloji.2010.754 INTRODUCTION The control of adult vectors (house flies, mosquitoes, and cockroaches) is accomplished primarily through the use of synthetic pyrethroids in Turkey and many parts of the world (Nadda et al. 2005, Akýner and Çaðlar 2006). These insecticides are synthetic derivatives of naturally occurring pyrethrins which are obtained from the plant Chrysanthemum cinerariafolium (Asteraceae). Among these insecticides Cypermethrin, Cyphenothrin, Deltamethrin, and Permethrin are recommended by the World Health Organization for control of different pest species (Anonymous 2006). However, in recent years some studies showed that frequent and incorrect applications have caused resistance to these insecticides (Demircan and Yilmaz 2005, Akýner and Çaðlar 2006). Over the next years we can expect new outbreaks of resistance to appear in other pest species throughout Turkey. Synergist effective substances are added at different rates, in a wide scale, with the objective of increasing the effectiveness of the insecticides, Received: 12.02.2009 / Accepted: 21.10.2010