The alder leaf beetle, Agelastica alni L. (Coleoptera: Chrysomelidae) is one of the most dangerous defoliator pests of Alnus spp., Corylus spp., Populus spp. and Salix spp. worldwide. In order to discover a significant biocontrol agent against this pest, thirteen local entomopathogenic fungal isolates were screened against different growth stages of A. alni with dose of 1 x 10(7) conidia under laboratory conditions. These included four isolates of Beauveria bassiana (Bals.) Vuill., seven isolates of Metarhizium anisopliae (Metsch.) Sorokin, one isolate of Myriodontium keratinophilum Samson and Polon and one isolate of Isaria fitmosorosea (Wize) Brown and Smith. The B. bassiana isolate KTU-24 showed the highest mortality rate (100 %) at all stages of A. alni within 14 days after inoculation. Dose mortality response bioassays showed that B. bassiana isolate (KTU-24) had the highest mortality rate (100 %) against 1st, 3rd instar larvae and adults of A. alni within 14 days after inoculation. These results indicate that B. bassiana KTU-24 seems to be a promising candidate for further studies as a biocontrol agent against A. alni.

Ips sexdentatus (Boerner) and I. Typographus (Linnaeus) (Coleoptera: Curculionidae) are considered to be important destructive pests of coniferous forests in Europe and Asia. In this study, the efficacy of Beauveria pseudobassiana strain ARSEF 9271 isolated from Dendroctonus micans (Kugelann) (Coleoptera: Curculionidae) was evaluated against I. Sexdentatus and I. Typographus adults. Insects were treated with different conidial concentrations of the fungus to determine the virulence. A conidial suspension of 1 × 108 conidia mL-1 caused 100% mortality in both I. Sexdentatus and I. Typographus within 5 and 7 days, respectively. Additionally, 100% mycosis was obtained in the concentration-response experiments for both insects. LC50 values of the fungus were calculated as 3.94 × 104 conidia mL-1 and 1.32 × 104 conidia mL-1 for I. Sexdentatus and I. Typographus, respectively. I. Sexdentatus and I. Typographus adults were also inoculated with a conidial suspension of 1 × 106 conidia mL-1 at inoculation rates of 0% (control), 25%, 50%, 75%, and 100% to determine the horizontal transmission of the fungus. Mortality values from horizontal transmission experiments were determined as 100% at all rates after 15 days at 20 °C under laboratory conditions. Our results indicate that B. Pseudobassiana ARSEF 9271 is a promising microbial control agent against the tested Ips species and can horizontally spread among a population of both I. Sexdentatus and I. Typographus.

The great spruce bark beetle, Dendroctonus micans (Kugelann) (Coleoptera: Curculionidae), has been a potential threat for Turkey and the entire Eurasian spruce forests for many years. Control strategies which have been applied so far are still insufficient to prevent its damage. A previous study has shown that a Beauveria isolate (ARSEF 9271) proved to be an efficient microbial control agent against the great spruce bark beetle. In this study, this isolate was identified as B. pseudobassiana based on the partial sequence of EF1‐α and ITS sequence. A conidial suspension (1 × 108/ml) of this fungus caused 100% mortality on both larvae and adults of D. micans within 5 and 6 days, respectively. Also, it caused 100% mycosis value on both larvae and adults. Mortality values of horizontal transmission experiments between larvae and adults which were contaminated with 1 × 106/ml spore suspension at 25%, 50%, 75% and 100% rates were determined as 100% after 15 days at 20°C under the laboratory conditions. We also determined the decrease of the damage in spruce wood block (15 × 25 cm) when the contamination rate of the larvae was increased. Our results indicate that B. pseudobassiana ARSEF 9271 seems to be a very promising biocontrol agent against D. micans.

The sycamore lace bug, Corythucha ciliata (Say) (Hemiptera: Tingidae), is one of the most destructive pests of plane trees (Platanus spp.) worldwide. This pest is a major nuisance in Europe since plane trees are very popular in parks. Thirteen entomopathogenic fungal strains including 4 isolates of Beauveria bassiana, 2 isolates of Beauveria pseudobassiana, 6 isolates of Metarhizium anisopliae, and 1 isolate of Isaria fumosorosea were screened against adults and nymphs of C. ciliata under controlled laboratory conditions in order to test their efficacy and search for an effective and safe biocontrol agent strategy. Each isolate was applied with a conidial concentration of 1 x 10(7) conidia mL(-1) to adults and nymphs of the pest. B. bassiana isolate KTU - 24 showed the highest mortality for both adults and nymphs with 86% within 2 weeks after inoculation. This isolate also caused the highest mycosis for adults and nymphs with 83% and 80%, respectively. Mortalities of the other fungal isolates ranged from 43% to 86% and from 36% to 73% for adults and nymphs. Therefore, B. bassiana KTU - 24 was selected for further dose mortality tests based on its high virulence and mycosis value. Dose-response mortality bioassays using 5 different concentrations (1 x 10(4), 1 x 10(5), 1 x 10(6), 1 x 10(7), and 1 x 10(8) conidia mL(-1)) were performed to determine the lethal concentration (LC50) of this isolate. Based on probit analysis, the LC50 values of isolate B. bassiana KTU -24 were calculated as 5.51 x 10(5) and 3.96 x 10(5) conidia mL(-1) against adults and nymphs, respectively. Consequently, B. bassiana KTU -24 appears to be a promising candidate for further investigations as a biocontrol agent against C. ciliata.