Chrysanthi Zarmakoupi

The management of Culex pipiens (Diptera: Culicidae), key vectors of arboviruses like West Nile virus, necessitates sustainable alternatives to chemical insecticides. This study screened indigenous entomopathogenic fungi (EPF) from forest soils in Achaia, Greece, for their larvicidal efficacy against Cx. pipiens biotype molestus. Fifteen fungal isolates were obtained via insect baiting and identified as Beauveria and Metarhizium species. A comprehensive bioassay at 1 × 10⁸ conidia mL⁻¹ revealed significant variation in pathogenicity after 72 h. Two isolates, Beauveria bassiana (BB) (Hypocreales: Cordycipitaceae) and Metarhizium anisopliae (K3(1)) (Hypocreales: Clavicipitaceae), exhibited the highest virulence among the tested isolates, each causing 60% mortality with a rapid median lethal time (LT₅₀) of ~18.5 h. Survival analysis, Cox modeling, and non-linear kinetic modeling (Gompertz/Richards) classified three distinct virulence clusters: high/rapid, moderate/consistent, and low/delayed. A pathogenicity network analysis and a composite virulence index further validated BB and K3(1) as the most effective candidates. These results demonstrate the high isolate specificity of fungal efficacy and underscore the importance of screening local fungal diversity. The identified high-virulence isolates represent promising, environmentally sound candidates for the development of targeted biopesticides. Future research should focus on formulation for aquatic environments and integration into resistance-resilient integrated vector management programs.

The two-spotted spider mite, Tetranychus urticae Koch, is a major agricultural pest whose control is increasingly constrained by resistance to synthetic acaricides. This study evaluated the long-term field efficacy of three commercial entomopathogenic fungal (EPF) biopesticides—Velifer^® (Beauveria bassiana), Metab^® (B. bassiana + Metarhizium anisopliae), and Botanigard^® (B. bassiana)—against larval and protonymph stages of T. urticae on two host plants, Italian cypress (Cupressus sempervirens) and sweet orange (Citrus sinensis). Two foliar applications were conducted during the 2023 growing season (25 May and 25 July), and mite populations were monitored for 140 days after the final application. A randomized complete block design was used, and efficacy was calculated using the Henderson–Tilton formula. All EPF treatments significantly reduced mite populations compared with the untreated control throughout the monitoring period. Velifer consistently achieved the highest suppression of larval populations, particularly on C. sinensis, with efficacy comparable to the chemical standard. Botanigard showed more gradual but sustained population reduction over time, whereas Metab exhibited lower but stable efficacy in all cases. Treatment performance was strongly influenced by host plant species and mite developmental stage, with larvae consistently more susceptible than protonymphs. On C. sinensis, Velifer achieved the highest larval suppression (84.6%), comparable to the chemical standard abamectin, while Botanigard and Velifer were most effective on C. sempervirens. Survival analysis confirmed isolate- and host-dependent differences in hazard effects over time. These results demonstrate that EPF-based products can provide sustained, long-term suppression of T. urticae under field conditions, supporting their integration into integrated pest management programs.

The citrus spiny whitefly Aleurocanthus spiniferus (Quaintance), recently found in Greece, causes severe damage to the leaves and fruits of tree crops, and treatment against it is urgent. In this work, integrated treatments for the management of the A. spiniferus pest on Citrus sinensis (L.) trees, which causes intense damage to orange orchards, were studied. The experiment was carried out in an orange orchard on the Aitoloakarnania plain, an agroforestry ecosystem, and three treatments were set up: (i) a combined treatment comprising the entomopathogenic fungi Beauveria bassiana and Cordyceps fumosorosea, (ii) treatment with the application of a tetramic acid-based formulation, (iii) the control treatment. The damage caused by A. spiniferus was estimated by determining the pest stages on the C. sinensis leaves, samples of which were collected and examined at the entomology laboratory of the Agriculture Faculty of the University of Ioannina for the calculation of populations. The experimental results of this work encourage us to further investigate the use of the treatments against whiteflies, highlighting the potential of EPF for integrated pest management (IPM) in citrus trees.

Entomopathogenic fungi (EPF) are one of the most environmentally friendly ways to control a plethora of chewing insects such as T. pityocampa, G. mellonella, and A. grisella. Bioassay of EPF on these highly damaging pests is considered important in the face of climate change in order to research alternative solutions that are capable of limiting chemical control, the overuse of which increases insects’ resistance to chemical compounds. In this study, the insecticidal virulence of Metarhizium robertsii isolates, retrieved from forest ecosystems, was tested on second-instar larvae of T. pityocampa, G. mellonella, and A. grisella. Bioassays were carried out in the laboratory, where experimental larvae were sprayed with 2 mL of a six-conidial suspension from each isolate. Mortality was recorded for 144 h after exposure. Mean mortality, lethal concentrations, sporulation percentage, and sporulation time were estimated for each isolate. Metarhizium isolates resulted in the highest mortality (89.2% for G. mellonella and 90.2% for A. grisella). Based on the LC₅₀ estimates determined by the concentration–mortality relationships for the tested fungal isolates, we demonstrated significant virulence on larvae of G. mellonella, A. grisella, and T. pityocampa. Our results indicate that entomopathogenic fungi have the potential to become a very useful tool in reducing chemical applications.

Greece’s olive oil production is significantly affected by the olive fruit fly Bactrocera oleae (Diptera: Tephritidae), and its presence is perceived when it is too late to act for damage recovery. In this work, some unexplored entomopathogenic fungi (EPFs) were studied for their efficacy on olive fruit fly pupae in soil samples. Olive grove soil samples were collected to evaluate the effect of EPFs in their natural environment. The parameters that were analyzed to evaluate the performance of EPFs on B. oleae included the adult survival time, pupa hatch time, and the presence of mycelium on B. oleae pupae and dead adults. The efficacy of some EPFs was highlighted by the mycelium present on dead B. oleae adults after treating pupae with fungal isolates on the soil substrate. The results showed that for the soil substrate, external fungal growth was observed in dead adults with A. contaminans, A. keveii, A. flavus P. lilacinum, and T. annesophieae (100%). Remarkably, the lowest male proportion for soil and non-soil substrates was for A. flavus (0.41–0.42) for the first time, for A. keveii (0.36), and for P. citreosulfuratum (0.41) on the soil-only substrate in contrast to the control treatment (0.5 for both substrates). Given the high infestation caused by the olive fruit flies in Greece, the results of the study emphasize to use of incorporating certain EPF-based biopesticides into integrated pest management (IPM) programs.

In this work, the ability of certain entomopathogenic fungi to control the olive fruit fly Bactrocera oleae (Diptera: Tephritidae), which significantly affects olive cultivation, was assessed. First, entomopathogenic fungi that often contribute to reducing pests, as well as B. oleae, were sought out. Puparia of B. oleae were collected from oil mills, and soil samples were collected from various olive grove regions of Greece. These soils were used as the substrate in which the effect of the entomopathogenic fungi on the B. oleae pupae was studied. In addition, the same treatments were studied in non-soil conditions. The results show that certain known entomopathogenic fungi are able, in their natural environment, to kill B. oleae pupae to a significant extent. The survival time for adults (days) was lower in the presence of Beauveria bassiana (Hypocreales: Cordycipitaceae), at 13.20 in the soil (5.56 ± 0.42) and non-soil (6.76 ± 0.46) conditions, compared to that of the control in soil (9.83 ± 083) and non-soil (9.90 ± 0.72) conditions. This is encouraging for Mediterranean regions where the presence of B. oleae significantly affects olive cultivation, while quality olive oil is in high demand.

The research on entomopathogenic viruses is of major significance as they could serve as alternatives to chemical pesticides. There are various types of entomopathogenic viruses; among them, Baculoviruses (BVs) are a potential option because they are eco-friendly and target specific. The experiment in question aimed to evaluate the effect of three insect-specific commercial viruses, Cydia pomonella Granulovirus (CpGV), Helicoverpa armigera Nucleopoyhedrovirus (HearNPV), and Phthorimaea operculella Granulovirus (PoG), on the third-instar larvae of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) and Thaumetopoea pityocampa Schiff (Lepidoptera: Notodontidae). The viruses’ concentrations when tested were 500 ppm, 1000 ppm, 1500 ppm, 3000 ppm, and 6000 ppm, and were applied on the eating medium. Both mortality and larval weight were monitored for 6 days. All three viruses had significant mortality rates on both moths (23.3–83.3% in the highest dose) and larval weights had considerable decreases (70–80% in the highest dose). Generally, noteworthy insecticidal action was recorded after 4 days and in doses higher than 1500 ppm. These results highlight that entomopathogenic viruses may infect species other than their natural host and can be implemented in terms of Integrated Pest Management.

Infestations of stored-product pests cause significant losses of agricultural produce every year. Despite various environmental and health risks, chemical insecticides are now a ready-to-use solution for pest control. Against this background and in the context of Integrated Pest Management research, the present study focuses on the potential insecticidal effect of caffeic acid at five different concentrations (250, 500, 750, 1500 and 3000 ppm), and their combination with Cydia pomonella Granulovirus (CpGV), Bacillus thuringiensis subsp. tenebrionis and Beauveria bassiana strain GHA on three major insect stored-product beetle species, Tribolium confusum (Coleoptera: Tenebrionidae), Cryptolestes ferrugineus (Coleoptera: Laemophloeidae) and Trogoderma granarium Everts (Coleoptera: Dermestidae). Treatment efficacy was expressed as mortality in relation to exposure time and adult species number. Compared to the control, the results showed a clear dose-dependent pesticidal activity, expressed as significant adult mortality at a high-dose application, although some of the combinations of caffeic acid concentrations with the other substances acted positively (synergistically and additively) and some negatively. Based on our results, bioinsecticides can be combined with plant compounds such as caffeic acid and be integrated with other modern IPM tools in storage facilities.