Hazelnut, a very important cash crop in Turkey, is frequently colonized by bark and ambrosia beetle species (Scolytinae). Some scolytine species may cause economic damage while other species do not; therefore, proper identification is important in orchard management. Extensive sampling demonstrated that the most common pest species in Turkey's hazelnut orchards are Anisandrus dispar, Xylosandrus germanus, and Xyleborinus saxesenii. Hypothenemus eruditus can also be common, but only colonizes branches that are already dead. Lymantor coryli, Hypoborus ficus, Taphrorychus ramicola, and Taphrorychus hirtellus are rare and do not causes damage to live plants. Xyleborinus saxesenii appears to have been frequently misidentified and misreported as either L. coryli or Xyleborus xylographus. The former is rare, and the latter probably does not occur in Turkey. To avoid future misidentifications, a dichotomous identification key is provided for bark and ambrosia beetles of hazelnut orchards in Turkey.

İstilacı bir böcek türü olan kahverengi kokarca, [Halyomorpha halys (Stål, 1855) (Hemiptera: Pentatomidae)], birçok kültür bitkisi için en tehlikeli zararlılardan biri olup, Çin, Japonya, Kore ve Tayvan orijinli bir türdür. Bu tür polifag olup, tarımsal ürünler, kabuklu yemişler, sebzeler ve süs bitkileri dahil olmak üzere yaklaşık 300 bitkide önemli zararlara sebep olmaktadır. Avrupa'da, ilk olarak 2004 yılında rapor edilmiş ve pek çok Avrupa ülkesine yayılmıştır. H. halys ilk olarak 2017 yılında İstanbul'dan, daha sonra aynı yıl Artvin ilinden Türkiye'ye girişi bildirilmiştir. Türkiye, dünyanın en büyük fındık üreticisi ve ihracatçısıdır ve Türkiye'de H. halys'in son zamanlarda ortaya çıkması ve yayılmaya devam etmesi, fındık üretimi ve ülkedeki diğer ürünler için gerçek bir potansiyel tehdit oluşturmaktadır. Bu çalışmada, bu zararlıya en benzer tür olan Rhaphigaster nebulosa ile karşılaştırılarak teşhiste dikkat edilmesi gereken kısımlar gösterilmiştir. Ayrıca Türkiye faunasında bulunan ve bu zararlı ile karıştırılabilecek diğer pis kokulu böcek türleri verilmiş ve zararlının mevcut durumu ve potansiyel tehdidi tartışılmıştır. Sonuç olarak, zararlı Türkiye'de ciddi bir şekilde ele alınmalı ve daha fazla yayılmadan mücadele programı başlatılarak kontrol altına alınmaya başlanmalıdır. Ayrıca, böceğin biyolojisi ve özellikle klasik biyolojik mücadeleyi de içeren uygun mücadele stratejileri üzerine çalışmalara acilen ihtiyaç duyulmaktadır.

Green shield bug (GSB) Palomena prasina (L.) causes significant yield and quality losses in hazelnut production of Turkey. Alive and dead adults of GSB were collected from the main hazelnut cultivation areas of Turkey during 2018 and 2019. The entomopathogenic fungi (EPF) were isolated from GSB individuals and identified by DNA sequencing of the internal transcribed spacer of the rRNA. Phylogenetic analysis based on the maximum likelihood method of these sequences with reference sequences retrieved from GenBank revealed that 20 native isolates were Beauveria bassiana (6), B. pseudobassiana (1), Cordyceps confragosa (5), Akanthomyces muscarius (4), Purpureocillium lilacinum (2), Isaria fumosorosea (1), and Bionectria sp. (1). Furthermore, the isolates were tested for their efficacy against GSB adults at 1 × 10⁸ spores mL⁻¹ concentration under laboratory conditions. Registered bio-insecticides were applied at the same concentration to compare the efficacy of the isolates. Beauveria spp. isolates were most effective among the tested isolates with LT₅₀ and LT₉₀ values ranging between 3.65–6.14 and 5.26–8.25 days, respectively. These isolates caused 100% mortality in GSB adults within 6–10 days. The isolates of A. muscarius (TR-OR-1) and P. lilacinum (TR-SM-7) were highly effective and caused 100% mortality 10 and 11 days after the treatment, respectively. These results indicated that some EPF isolates obtained in this study are more promising as an alternative control agent against GSB.

Green shield bug (GSB), Palomena prasina L. (Hemiptera: Pentatomidae), is an important pest of hazelnut orchards causing significant yield and quality losses in Turkey. The application of insecticides is the only option to manage GSB in Turkey; however, effective and alternative eco-friendly control practices are needed to manage the pest in the country. Surveys of egg parasitoids using frozen sentinel egg masses were conducted in the main hazelnut-growing regions of Turkey. Furthermore, the composition of native species parasitising GSB eggs and their parasitism rates were determined under field conditions. A total of 11,570 eggs were exposed to field conditions, of which 10,386 eggs were recovered from the surveyed area after 7 days in 2018 and 2019. Trissolcus cultratus, Tr. belenus, Tr. sp1, Telenomus turesis, and Te. sp1 were morphologically identified as egg parasitoids, which was molecularly confirmed based on the cytochrome c oxidase subunit I gene (CO1). The parasitism rate was 9.3% for all eggs exposed to field conditions. Trissolcus cultratus was the predominant species and responsible for 70.06% of the parasitism rate, followed by Tr. belenus (15.75%), Te. turesis (10.26%), Te. sp1 (3.83%), and Tr. sp1 (0.01%). The existence of Tr. cultratus is reported for the first time in Turkey. The egg parasitoid species of GSB determined in this study witnessed the presence of natural parasitism in the natural habitat of the pest. Furthermore, it must be considered that Tr. cultratus can act as a facultative hyperparasitoid.

Ambrosia beetles, Anisandrus dispar Fabricius, Xylosandrus germanus Blandford, and Xyleborinus saxesenii Ratzeburg (Coleoptera: Curculionidae: Scolytinae) are among the most significant hazelnut pests in Turkey. The control of these pests is difficult and expensive due to their biology. The present study aimed to isolate entomopathogenic fungi (EPF) from A. dispar, X. germanus, and X. saxesenii individuals that were obtained from the main hazelnut production areas of Turkey, characterize the EPF isolates using internal transcribed spacer (ITS)-DNA sequencing and iPBS profiling, and determine the efficacy of the isolates against A. dispar, X. germanus, and X. saxesenii under laboratory conditions. Phylogenetic analyses based on ITS revealed that the 47 native isolates were Beauveria bassiana (11), B. pseudobassiana (8), Cordyceps fumosorosea (6), Cordyceps farinosa (1), Akanthomyces lecanii (13), Purpureocillium lilacinum (3), Clonostachys rosea (2) and Metarhizium anisopliae (3). For the first time, the primer binding site (PBS) marker system, based on retrotransposons, was used to discriminate successfully among the EPF species. Some isolates of B. bassiana, B. pseudobassiana, C. fumosorosea, A. lecanii, and M. anisopliae caused 100% mortality of the beetle species within 7 to 9 days. The findings of this study indicated that some isolated entomopathogenic fungi provide an essential basis for the development of bioproducts, as well as a promising alternative method for controlling these ambrosia beetles.