Entomopathogenic fungi (EPF) can colonize plant tissues and serve crops not only as biopesticides but also as biostimulants that promote plant growth and trigger defense mechanisms. In this context, field trials were conducted evaluating two commercial strains of the entomopathogen Beauveria bassiana (Hypocreales: Cordycipitaceae), GHA (Botanigard) and PPRI 5339 (Velifer^® ES) and a wild strain (AP0101) isolated from Achaia, Greece. The three strains were investigated in the field for their endophytic effects on melon Cucumis melo (Cucurbitales: Cucurbitaceae) and strawberry Fragaria sp. (Rosales: Rosaceae) plants and in particular for their ability to colonize plant tissues, control infestations of sucking insects Aphis gossypii (Hemiptera: Aphididae), Chaetosiphon fragaefolii (Hemiptera: Aphididae) and Frankliniella occidentalis (Thysanoptera: Thripidae), and improve plant growth parameters (plant height, number of flowers and fruits). All experimental fungal strains successfully colonized both plants. A significant decrease in the aphid and thrip populations was observed in the treated plants compared to the untreated control. As for plant growth, the number of flowers and fruits was significantly increased in plants treated with B. bassiana strains AP0101 and PPRI 5339. Our results clearly indicate that fungal endophytes can efficiently act as dual action agents demonstrating both insecticidal and growth-promoting effects.

Increasing commercial demands from the textile and food industries are putting strong pressure on the cultivation of cotton and its derivatives to produce high yields. At the same time, cotton has high nutrient and irrigation requirements and is highly susceptible to insect pests. Coating cotton seeds with beneficial fungi could address these problems. The aim of this study was to investigate the growth of cotton using (A) conventional seeds and (B) seeds coated with the entomopathogenic fungus Beauveria bassiana (Hypocreales: Cordycipitaceae). The experiment was conducted in a greenhouse of the Department of Agriculture of the University of Ioannina, in a completely randomized design. The growth characteristics of cotton plants were recorded weekly while the fresh weight and dry matter of the leaves, shoots and roots of the developed cotton plants were calculated at the end of the experiment. Weekly determination of total chlorophyll content (TCHL) was used as an indicator of plant robustness during the 80-day experiment. Many cotton growth parameters of treated plants, like number of leaves, shoots and apical buds, plant height, stem diameter, fresh and dried biomass and TCHL, were significantly higher than those of the untreated ones. Apart from plant growth, naturally occurring by Aphis gossypii (Hemiptera: Aphididae) infestation which also monitored for six weeks. A significantly lower aphid population was recorded for inoculated plants after the fifth week compared to the control. The overall evaluation revealed that B. bassiana coating treatments appear to have a significant biostimulatory and bioinsecticidal effect. Our results could represent responsive applications to the demands of intensive cotton growing conditions.

As climate change is an imminent threat to the environment and agriculture, there is an increasing need to find immediate solutions capable of compensating for water deficits even in semi-arid conditions. This study is focused on the evaluation of the vegetative growth of grapevine plants Vitis vinifera L., of the Greek variety “Debina” in a water deficit environment, with the application of two bacterial-based formulations: one with Bacillus amyloliquefaciens (strain QST 713) and one with Sinorhizobium meliloti (strain cepa B2352). The two formulations were tested under rational irrigation (100% of Available Water) and deficit irrigation (57% of AW). After 140 days, plant growth parameters, such as total plant growth length, leaf area, roots, shoots, and leaves dry biomass showed better performance on treatments with plant growth-promoting rhizobacteria (PGPR) formulations under either rational or deficit irrigation conditions. In addition, the metabolic response of the grapevine plants to the deficit irrigation stress, such as the total chlorophyll, leaf relative water, total phenolic, and proline content, proved to be enriched on the treatments with PGPR formulations during this experiment. The two formulations, in conditions of abiotic stress, achieved to almost compensate for the irrigation deficit, boosting the plant metabolism. This study reveals the need for further research on PGPR biostimulants, as this first trial of these formulations on grapevine could be significant in the case of water scarcity and climate change.

In this study, the bioinsecticidal action of a commercial formulation with Beauveria bassiana was evaluated on the new sucking pest in Greece: Halyomorpha halys, of the kiwifruit. Additionally, the biostimulant potential of the same formulation was studied on kiwi growth. The application was performed in three different ways in a commercial field of kiwi crop A. deliciosa “Hayward” field in Arta, Greece: (i) trunk spray, (ii) root injection, and (iii) trunk inoculation. During the 2 years seasons of the experiment, weekly measurements of the H. halys population were determined. The insect is sucking plants nutrients; therefore, the total chlorophyll content in the leaves of the treatments was recorded weekly. In addition, the percentage of infested kiwifruits was estimated at the end of the experiment. Moreover, to study the biostimulant potential of the formulation, growth measurements on stems and leaves were performed during the experiment. Finally, at the kiwi harvest point, the fruit biomass, dimensions, and weight were obtained, and the leaves’ proline content was evaluated. The results encourage us to further study this EPF formulation as the bioinsecticidal effect was noted by the reduction in H. halys population, and biostimulant action was perceived by the higher plant biomass.

The Greek endemic Bornmuellera emarginata , known for its Ni hyperaccumulation capacity, is a promising candidate species for use in agromining. At the same time, the installation of photovoltaic systems on agricultural land has recently been increasing. Field observations that populations of this species usually occupy shaded places under shrubs or trees led us to study the effect of different shading levels on the growth of B. emarginata , with a view to combine the cultivation of the species with photovoltaic panels in the same area. The experiment was conducted under greenhouse conditions and lasted 210 days after sowing (DAS). Seeds were sown directly into 2‐L pots filled with ultramafic soil collected from the field. Three plant samplings (81, 140, and 210 DAS) were conducted during the experiment to determine a set of morphological and physiological parameters of the species (fresh and dry plant biomass, plant height, number of lateral shoots, total number of leaves, proline and chlorophyll concentrations) alongside with its nickel yield at different levels of shading (0%, 20%, 35%, 60%, and 90%). Growth of B . emarginata was only significantly affected at the highest shading level. Nickel yield of the species increased over time and was maximized at the end of the experiment. The highest nickel yield per plant was observed at the intermediate shading level (35%). Bornmuellera emarginata can be considered as a candidate nickel hyperaccumulator for cultivation in ultramafic or nickel‐polluted areas under photovoltaic panels with corresponding shading, providing important environmental benefits.

The commercial value of kiwifruit is determined mostly by its nutritional composition and antioxidant content. The enrichment of these traits in an era where climate change affects kiwi growth conditions is worth investigating via the application of biostimulants that enhance plant growth. In this work, we evaluated the effects of three commercial biostimulants on the metabolism and growth characteristics of the Actinidia deliciosa cultivar ‘Hayward’: (I) a humic and fulvic-based biostimulant, (II) a glycine–betaine–proline-based biostimulant, and (III) a vegetal amino acid-based biostimulant. A biostimulant-free treatment was used as a control. In the two-year experiment (2022 and 2023), the growth characteristics of kiwi trees were measured, such as stem length, the number of leaves, leaf area, and fresh and dry biomass at the end of each growing season. The leaves’ total chlorophyll, total phenolics, and proline content were detected during the two seasons in order to obtain more insights into plant metabolism. Κiwifruit qualities and antioxidant traits, such as total soluble solids, titratable acidity, firmness, fresh and dry biomass, DPPH, and ascorbic acid (vitamin C), were recorded during the postharvest life for each season. Data analysis illustrated the beneficial impact of some biostimulants on several of the previously mentioned parameters, such as antioxidant kiwifruit traits, especially in the case of glycine–betaine–proline-based acid-based biostimulants.