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The genus Haritalodes Warren, 1890 is represented by 12 species worldwide except in the Nearctic and Neotropical regions. Haritalodes derogata (Fabricius, 1775), commonly known as the cotton leaf roller moth, is the most widely distributed species of the genus and is common in the West Palaearctic Region. This species is one of the most serious pests of Malvaceae. The larvae primarily feed on the leaves, and severe population levels may lead to significant yield loss in the primary host, cotton. In a survey in 2023, the shrubs of the Hibiscus sp. were found to be infested by a group of larvae with a very dense population feeding on the leaves in Trabzon Province, Türkiye. The larvae were reared for pupation and adult emergence. Morphological identification according to male and female genitalia as well as sequencing of the mitochondrial cytochrome oxidase region I (COI) from larvae and adults revealed that the species is H. derogata. This is the first report of the genus Haritalodes and Haritalodes derogata in Türkiye.

Insect adipokinetic hormones (AKHs) are neuropeptides with a wide range of actions, including the control of insect energy metabolism. These hormones are also known to be involved in the insect defence system against toxins and pathogens. In this study, our aim was to demonstrate whether the application of external AKHs significantly enhances the efficacy of the entomopathogenic fungus Isaria fumosorosea in a model species (firebug Pyrrhocoris apterus ) and pest species (Egyptian cotton leafworm Spodoptera littoralis and pea aphid Acyrthosiphon pisum ). It was found that the co-application of Isaria with AKHs significantly enhanced insect mortality in comparison to the application of Isaria alone. The mode of action probably involves an increase in metabolism that is caused by AKHs (evidenced by the production of carbon dioxide), which accelerates the turnover of Isaria toxins produced into the infected insects. However, several species-specific differences probably exist. Intoxication by Isaria elicited the stimulation of Akh gene expression and synthesis of AKHs. Therefore, all interactions between Isaria and AKH actions as well as their impact on insect physiology from a theoretical and practical point of view need to be discussed further.

The chitinase B (chiB) and C (chiC) genes and flanking regions from a local isolate of Serratia marcescens were cloned individually and sequenced. Results showed that these chiB and chiC genes have a 96 % maximum similarity with chiB and chiC from different S. marcescens species (GenBank numbers Z36295.1 and AJ630582.1, respectively). The amplified chiB fragment, including some upstream and downstream regions, is 1,689-bp long with an open reading frame of 1,500 bp. The amplified fragment of chiC is 1,844 bp with an open reading frame of 1,443 bp. These sequences were submitted to the GenBank with accession numbers JX847796 (chiB) and JX847797 (chiC). Putative promoter regions and Shine-Dalgarno sequences were identified in both genes. The genes were cloned into a shuttle vector and the constructs were designated as pHYSB and pHYSC, respectively. Both plasmids were introduced separately into kurstaki and israelensis strains of Bacillus thuringiensis and the insecticidal activities of the engineered B. thuringiensis strains were assayed in larvae of Galleria mellonella and adult of Drosophila melanogaster. Engineered B. thuringiensis strains showed higher insecticidal activity than parental strain and the parental S. marcescens. In addition, pHYSB and pHYSC were stable over 16 daily passages under non-selective conditions in transformed B. t. israelensis 5724 strain.

A novel bioactive molecule produced by Bacillus thuringiensis subsp. kurstaki Bn1 (Bt-Bn1), isolated from a common pest of hazelnut, Balaninus nucum L. (Coleoptera: Curculionidae), was determined, purified, and characterized in this study. The Bt-Bn1 strain was investigated for antibacterial activity with an agar spot assay and well diffusion assay against B. cereus, B. weinhenstephenensis, L. monocytogenes, P. savastanoi, P. syringae, P. lemoignei, and many other B. thuringiensis strains. The production of bioactive molecule was determined at the early logarithmic phase in the growth cycle of strain Bt-Bn1 and its production continued until the beginning of the stationary phase. The mode of action of this molecule displayed bacteriocidal or bacteriolytic effect depending on the concentration. The bioactive molecule was purified 78-fold from the bacteria supernatant with ammonium sulfate precipitation, dialysis, ultrafiltration, gel filtration chromatography, and HPLC, respectively. The molecular mass of this molecule was estimated via SDS-PAGE and confirmed by the ESI-TOFMS as 3,139 Da. The bioactive molecule was also determined to be a heat-stable, pH-stable (range 6-8), and proteinase K sensitive antibacterial peptide, similar to bacteriocins. Based on all characteristics determined in this study, the purified bacteriocin was named as thuricin Bn1 because of the similarities to the previously identified thuricin-like bacteriocin produced by the various B. thuringiensis strains. Plasmid elution studies showed that gene responsible for the production of thuricin Bn1 is located on the chromosome of Bt-Bn1. Therefore, it is a novel bacteriocin and the first recorded one produced by an insect originated bacterium. It has potential usage for the control of many different pathogenic and spoilage bacteria in the food industry, agriculture, and various other areas.

Background: In order to find and identify more toxic insecticidal Bacillus thuringiensis Berliner (Bt) strains, a survey was carried out of B. thuringiensis isolate pests belonging to Coleoptera, Lepidoptera and Diptera and from soils in hazelnut fields. Of 16 isolates having Bacillus cereus-B. thuringiensis morphology, eight were classified as B. thuringiensis because of the production of parasporal delta-endotoxin crystals., Results: In this study, eight isolates of B. thuringiensis from hazelnut pests (isolates Bn1, Mm2, Mnd and Xd3) and from hazelnut soils (isolates 6, 27, 40 and 46) have been characterised in detail. These isolates were compared with reference strains by electron microscopy, SDS-PAGE analysis, cry gene content, serological test and insecticidal activity., Conclusion: Results indicate that Bn1 and MnD are B. thuringiensis subsp. kurstaki, and Mm2 and Xd3 are B. thuringiensis subsp. tenebrionis. In addition, isolate 6 is B. thuringiensis subsp. israelensis, isolates 27 and 46 are B. thuringiensis subsp. kumamotoensis and isolate 40 is B. thuringiensis subsp. indiana. The four B. thuringiensis isolates from hazelnut pests may be valuable as biological control agents against coleopteran and lepidopteran insects.

In order to detect and identify the most toxic Bacillus thuringiensis strains against pests, we isolated a B. thuringiensis strain (Bn1) from Balaninus nucum (Coleoptera: Curculionidae), the most damaging hazelnut pest. Bn1 was characterized via morphological, biochemical, and molecular techniques. The isolate was serotyped, and the results showed that Bn1 was the B. thuringiensis serovar, kurstaki (H3abc). The scanning electron microscopy indicated that Bn1 has crystals with cubic and bipyramidal shapes. The Polymerase Chain Reactions (PCRs) revealed the presence of the cry1 and cry2 genes. The presence of Cry1 and Cry2 proteins in the Bn1 isolate was confirmed via SDS-PAGE, at approximately 130 kDa and 65 kDa, respectively. The bioassays conducted to determine the insecticidal activity of the Bn1 isolate were conducted with four distinct insects, using spore-crystal mixtures. We noted that Bn1 has higher toxicity as compared with the standard B. thuringiensis subsp. kurstaki (HD-1). The highest observed mortality was 90% against Malacosoma neustria and Lymantria dispar larvae. Our results show that the B. thuringiensis isolate (Bn1) may prove valuable as a significant microbial control agent against lepidopteran pests.

Studying the bacteria of hazardous insects allows the opportunity to find potentially better biological control agents. Therefore, in this study, bacteria from summer chafer (Amphimallon solstitiale L., Coleoptera: Scarabaeidae) we isolated and identified the insecticidal effects of bacteria isolated from A. solstitiale and Melolontha melolontha L. (common cockchafer, Coleoptera: Scarabaeidae) and the mixtures of these bacterial isolates were investigated on A. solstitiale larvae. Crystals from Bacillus sp. isolated from M. melolontha were also purified, and tested against the second and third-stage larvae of A. solstitiale. The bacterial isolates of A. solstitiale were identified as Pseudomonas sp., Pseudomonas sp., Bacillus cereus and Micrococcus luteus, based on their morphology, spore formation, nutritional features, and physiological and biochemical characteristics. The insecticidal effects of the bacterial isolates determined on the larvae of A. solstitiale were 90% with B. cereus isolated from A. solstitiale, and 75% with B. cereus, B. sphaericus and B. thuringiensis isolated from M. melolontha within ten days. The highest insecticidal effects of the mixed infections on the larvae of A. solstitiale were 100% both with B. cereus+B. sphaericus and with B. cereus+B. thuringiensis. In the crystal protein bioassays, the highest insecticidal effect was 65% with crystals of B. thuringiensis and B. sphaericus isolated from M. melolontha within seven days. Finally, our results showed that the mixed infections could be utilized as microbial control agents, as they have a 100% insecticidal effect on the larvae of A. solstitiale.

A local isolate of Bacillus thuringiensis Mm2 had insecticidal activity against the larvae of Melolontha melolontha, Agelastica alni, Leptinotarsa decemlineata and Amphimallon solstitiale and produced a 65 kDa protein. SDS-PAGE profile of B. thuringiensis Mm2 was compared with those of 29 different Cry3Aa producers which verified Cry3Aa biosynthesis by the isolate. The cry3Aa gene of Mm2 was cloned, sequenced and the deduced amino acid sequence was compared with the cry3Aa sequences of ten different quaternary ranks. Its identity to these sequences ranged between 97.4% and 99.2%. The gene was next cloned into E. coli-Bacillus shuttle vector pNW33N and expressed at a low level in B. subtilis 168.