This study was conducted in 2024-2025 in the laboratories of Ege University, Faculty of Agriculture, Department of Plant Protection. Spodoptera littoralis (Boisduval, 1833) (Lepidoptera: Noctuidae) is an important pest in Türkiye and causes extensive economic losses in many cultivated crops. During our field observations, some blackening and dead individuals were observed in Leptinotarsa decemlineata (Say, 1824) (Coleoptera: Chrysomelidae) larvae. As a result of the isolations made from blackened larvae and plant samples, 6 different bacterial isolates were obtained. Pseudomonas fluorescens Migula (Pseudomonadales: Pseudomonadaceae) strain 184, whose entomopathogenic effect was proven in our previous studies and molecular diagnosis and sequence analysis were performed, was also used in these tests. As a result of two seperated experiments, it was observed that endophytic bacteria isolates caused 20 to 93% mortality compared to untreated negative control. As a result of conventional and molecular identification and sequence analysis, the bacterial isolates with the highest entomopathogenic effect against S. littoralis larvae were isolates 441 and 442, which were definitively identified as Serratia marcescens J. and Enterobacter cloacae M. (Enterobacterales: Enterobacteriaceae), respectively. This study revealed that these bacteria may have potential for biological control against S. littoralis.

Bacterial spot of tomato, caused by Xanthomonas euvesicatoria, is a serious disease that causes yield and quality losses. There has been increased focus on biological control agents as alternatives to chemical pesticides in plant disease management. In this study, 313 endophyte and epiphyte bacterial isolates, from tomato plants sampled from different locations in Turkey, were assessed for their potential for plant growth promotion and biocontrol efficacy against X. euvesicatoria. Results obtained from in vitro assays were evaluated using the weighted ranking method, and 15 isolates were selected for in planta biocontrol evaluation against X. euvesicatoria. In efficacy tests, bacteria were introduced into tomato plants by biopriming of seeds or by spraying whole plants. The two most effective isolates reduced bacterial spot by 40–45% after seed biopriming, and 30–41% from shoot application, compared to the non-treated experimental controls. Sequence analysis using 16S rRNA primers identified one representative isolate (coded KD 91/1) as Pseudomonas putida. Tomato plants bioprimed with KD 91/1 through seed treatment had greatest biomass compared to that for the other tested bacteria. The population of P. putida KD 91/1 in tomato tissues after pathogen inoculation was approx. 7.2 × 104 cfu g-1 in shoots and 1 × 105 cfu g-1 in roots. This study indicates that antagonistic P. putida isolates are promising candidates for biological control of X. euvesicatoria.

Clavibacter michiganensis subsp. michiganensis (Cmm), is a devastating bacterial disease agent causing bacterial wilt and canker in tomatoes. There is no definitive solution to prevent yield losses by Cmm in tomatoes. Moreover, there is currently no commercially successful Cmm resistant tomato cultivar on the market. Therefore, we aimed to determine the tolerance level of some tomato accessions to Cmm in the present study. For this purpose, we screened seven tomato accessions representing four species (Solanum arcanum, S. habrochaites, S. pennellii, and S. peruvianum) from Peru, Ecuador, and Mexico against the highly virulent isolates Cmm-244 and Cmm-9. A root immersion method was used to identify new sources of resistance to this important disease. Two accessions, S. habrochaites LA1777, and S. arcanum LA2157 were found to be moderate and highly tolerant, respectively, and could serve as tolerance resources for tomato breeding in Türkiye. These materials can also be investigated more extensively to determine their intrinsic Cmm tolerance mechanism.

The rose aphid, Macrosiphum rosae (L.) (Hemiptera: Aphididae), is one of the most common pests of rose plants. This study evaluated the effects of four different doses of Neem Azal-T/S, containing the active ingredient Azadirachtin A, and a dose of Serratia nematodiphila (1x108 cfu/ml) on M. rosae over 72 hours. The experiment was conducted in a climate chamber under controlled conditions (25±1 °C, 60±5% relative humidity, and a 16:8 light-dark photoperiod). The results showed that Neem Azal-T/S led to mortality rates of 12.5%, 17.5%, 60%, and 77.5%, respectively, while S. nematodiphila resulted in a 78% mortality rate after 72 hours. In the control group, mortality was 0.75%, while mortality rates for the treatment groups were 1.25 (Neem_1), 1.75 (Neem_2), 6.00 (Neem_3), 7.00 (Neem_4), and 8.25 (S. nematodiphila). Statistical analyses showed significant differences between all treatment groups and the control. In conclusion, this study demonstrated that both Neem Azal-T/S and S. nematodiphila significantly increased mortality rates in M. rosae compared with the control. Additionally, this study is the first record of the presence of S. nematodiphila in Türkiye and the first information on its entomopathogenic effect on M. rosae in the worldwide, supporting the potential of biological methods in managing rose aphids and emphasizing the importance of biological control strategies in agricultural pest management.