Ips sexdentatus (Coleoptera: Curculionidae) is one of the most destructive pests of the spruce trees in Europe. In this study, we have isolated and characterized culturable bacteria from I. sexdentatus and tested their insecticidal activity against the last instar larvae of the pest as a possible biocontrol agent. A total of eight bacterial isolates was determined and four of them were identified at species level, and the others were identified at genus level. Isolates were identified as Stenotrophomonas maltophilia (Is1), Rahnella sp. (Is2), Pseudomonas sp. (Is3), Bacillus sp. (Is4), Alcaligenes faecalis (Is5), Panteoea agglomerans (Is6), Pseudomonas fluorescens (Is7) and Serratia sp. (Is8) based on their morphological, biochemical and molecular characteristics. Insecticidal effects of bacterial isolates were performed on the last instar larvae of the pest. The highest insecticidal activity was obtained from P. fluorescens (Is7) with 73% mortality within 10 days after inoculation (p < 0.05). Mortality values of the other isolates ranged from 20 to 53%. This study suggests that Pseudomonas fluorescens (Is7) seems to be a good candidate as a possible biocontrol agent against I. sexdentatus, and provides suitable strains that can be modified to express insecticidal toxins and/or other detrimental substances to develop new control methods for I. sexdentatus.

B u çalışmada, Türkiye'de Karadeniz Bölgesi'nden toplanan Avrupa danaburnu (Gryllotalpa gryllotalpa L., Orthoptera: Gryllotalpidae) populasyonundan bir nematod suşu izole edildi. Suş, morfometrik ve moleküler (ITS kısmi sekansı) özelliklerine göre Oscheius myriophila olarak tanımlandı. Dauer jüvenillerin bu türleri Rhabditis myriophila (Poinar, 1986)'ya benzemekle birlikte, O. myriophila sahip olduğu; vücut uzunluğu (571.3-693.9) ve baştan sinir halkasına olan uzunluk (100-116.8), ve küçük kuyruk uzunluğu (53.4-76.8) ve anüs genişliği (10.4-13.8) özellikleriyle farklıdır. Bu evre, nematodu bir kılıf gibi kuşatan ikinci evre kütikül içinde bulunan üçüncü evre jüvenildir. rDNA'nın ITS bölgesinin sıraları bu tanımlamayı doğruladı. Bu tür G. gryllotalpa'da ilk kez kaydedildi.

No abstract

Entomopathogenic nematodes were isolated from a population of larvae of the cutworm Agrotis segetum Denis & Schiffermüller, 1775 (Lepidoptera: Noctuidae) collected from the Black Sea region of Turkey in 2009 using White traps. The isolated nematodes were identified as Steinernema websteri based on morphological and molecular properties. Steinernema websteri was also found for the first time in Turkey and in A. segetum larvae. The efficacy of isolates was tested on A. segetum larvae in plastic boxes. Different concentrations of nematodes (100, 300, and 500 infective juveniles (IJs) g -1 of dry sand) at 23 ± 1 °C were used. The obtained mortality percentages were 100% with the concentration of 500 IJs g -1 of dry sand within 5 days after application under laboratory conditions. Our results indicate that S. websteri is a promising biological control agent against A. segetum, which is one of the most serious subsoil pests plaguing agricultural crops and fruits worldwide.

Cimbex quadrimaculatus (Hymenoptera: Cimbicidae) is one of the serious pests of almonds in Turkey and worldwide. Since there is no effective control application against this pest, it has been a serious problem up to now. Therefore, we aimed to find an effective bacterium that can be utilized as a biocontrol agent against C. quadrimaculatus in pest management. We isolated seven bacteria from dead and live C. quadrimaculatus larvae, and evaluated the larvicidal potency of all isolates on the respective pest. Based on the morphological, physiological, biochemical and molecular properties (partial sequence of 16S rRNA gene), the isolates were identified to be Bacillus safensis (CQ1), Bacillus subtilis (CQ2), Bacillus tequilensis (CQ3), Enterobacter sp. (CQ4), Kurthia gibsonii (CQ5), Staphylococcus sp. (CQ6) and Staphylococcus sciuri (CQ7). The results of the larvicidal activities of these isolates indicated that the mortality value obtained from all treatments changed from 58 to 100 %, and reached 100 % with B. safensis (CQ1) and B. subtilis (CQ2) on the 3rd instar larvae within 10 days of application of 1.89 × 10(9) cfu/mL bacterial concentration at 25 °C under laboratory conditions. Findings from this study indicate that these isolates appear to be a promising biocontrol agent for C. quadrimaculatus.