During field surveys conducted from July to October 2018–2020 in the eastern part of Georgia (Caucasus region), 145 out of 8000 (1.8%) and 147 out of 6600 (2.2%) grapevine plants, respectively, from mother stock/collection fields and commercial vineyards, were found exhibiting typical or suspicious grapevine yellows (GY) symptoms. Most of the symptomatic grapevine plants of Georgian cultivars showed mild symptoms with no berry alterations. Leaf samples from symptomatic plants were analyzed by serological (DAS- -ELISA) and molecular (two previously published protocols of TaqMan triplex real-time PCR, here named Set I and Set II) tools for detecting GY-associated phytoplasmas. The presence of GY phytoplasmas was not detected in any examined grapevines by a serological method. GY phytoplasmas were identified in 22.41% and 6.9% symptomatic plants from mother stock and collection vineyards and in 48.3 and 19.0% symptomatic plants from commercial vineyards by Set I and Set II PCRs, respectively. As expected from previous studies reporting the wide presence of bois noir (BN) in Georgian vineyards, ‘Candidatus Phytoplasma solani’(CaPsol) was detected in most phytoplasma-infected plants (47.6%), with the highest infection rate in Chardonnay. Phytoplasmas belonging to taxonomic group 16SrV were detected in 45.6% of the phytoplasma-infected grapevines. To the best of our knowledge, this is the first report of 16SrV phytoplasmas in Georgia and in the Caucasus region. Further molecular typing of 16SrV phytoplasma strains is necessary to determine if such strains are associated with flavescence dorée (FD). The knowledge of typical GY symptoms and the utilization of accurate diagnostic tools are crucial for preventing pathogen spread and producing healthy planting material. Based on the results obtained in this study, the presence of BN and 16SrV phytoplasmas should be monitored in the next years using triplex real-time PCR.

The fumigation toxicity of Melaleuca alternifolia (Maid. & Betche) Cheel. (Myrtales: Myrtaceae) essential oil and its major fractions was studied under laboratory conditions against adults of Sitophilus oryzae L. (Coleoptera: Curculionidae) to protect wheat grains ( Triticum aestivum L.) (Poales: Poaceae) from this global pest that destroys the host plant during storage. By analyzing M. alternifolia essential oil (EO) using GC/MS terpinen-4-ol and γ-terpinene were detected as major components. In the fumigation toxicity, M. alternifolia EO showed the highest toxicity (LC50 = 0.31 μl · l–1 air), followed by terpinen-4-ol (LC ₅₀ = 23.65 μl · l–1 air) and γ-terpinene was the least toxic (LC ₅₀ = 43.55 μl · l–1 air). When tested for their insecticidal activities against S. oryzae in stored wheat, no progeny emerged after 3 months of treatment with M. alternifolia EO at 10 mg · g–1 or with terpinen-4-ol and γ-terpinene for 2 months. However, none of these compounds could protect wheat grain from damage throughout the entire study period (4 months). Interestingly, all tested compounds at the highest application rate did not show any phytotoxic effects after 4 months of storage.

Metcalfa pruinosa (Say, 1830) was recorded for the first time in Poland, in the city of Warsaw. This Nearctic species of the Flatidae family was introduced into Europe in the late 1970s and has expanded its range ever since. We provide data on the first record as well as briefly characterize the insect in terms of its diagnostic features, biology and potential harm to agriculture and the environment.

The aim of this study is to find bacterial strains with antagonistic effects against Fusarium oxysporum f. sp. lycopersici ( Fol) and Ascochyta sp, which are phytopathogens responsible for fusarium wilt of tomato and ascochyta blight of peas, respectively. One hundred thirty- six bacteria isolated from the rhizosphere of tomatoes were screened. Five strains with the largest inhibition zones were selected. These strains were identified by the phenotypic method, later confirmed by sequencing of 16S rDNA. All strains belonged to the genus Bacillus spp. Their inhibition capacity was evaluated by the direct method by doing a dual culture, the inhibition rates ranged from 44.32 ± 0.8 to 61.36 ± 0.2 against Fol and 62.04 ± 0.8 to 74.1 ± 0.2% against Ascochyta sp. They were then evaluated by the indirect method by evaluating, on one hand, the antifungal effect of the volatile compounds produced by the strains and on the other hand, the antifungal effect of the filtrates. The results showed that volatile compounds inhibited plant pathogens’ growth with average inhibition rates of 55% against Fol and 17% against Ascochyta. For filtrates, the average inhibition rates were 33.01% against Fol and 33.74% against Ascochyta sp. Finally, the plant growth promoting rhizobacteria (PGPR) effect of B. halotolerans RFP57 was evaluated. This involved assessing their ability to stimulate the germination of tomato seeds and the growth of their vegetative organs. The results showed significant improvement in treated seedlings compared to controls. All these results show that the strains selected for this study have the potential for use as a biocontrol agent. However, it is clear that further in-depth studies are needed to confirm their true potentiality.