Fungal lectins, with their specific glycan-binding activity, represent promising biopesticide candidates. This study investigates the potential of six fungal lectins to control Colorado potato beetle (CPB) larvae (Leptinotarsa decemlineata). In vitro feeding trials with recombinant lectins were performed to evaluate their individual toxicity. Marasmius oreades agglutinin (MOA) caused significantly higher mortality than the other lectins, whereas Coprinopsis cinerea lectin 2 (CCL2) and Aleuria aurantia lectin (AAL) completely inhibited weight gain. Functional analysis of MOA mutants revealed that both carbohydrate-binding and proteolytic domains are essential for toxicity. MOA binds to midgut glycoproteins in CPB larvae, disrupting midgut epithelium. Histology and ultramicroscopy showed that MOA causes loss of apicobasal polarity and detachment of basal lamina. No acute toxicity of lectins against adult European honeybees (Apis mellifera) was found; however, significant sublethal effects on larval development were observed. MOA shows promise as a selective bioinsecticide for sustainable CPB control with minimal nontarget effects.

Strawberry plants are attacked by various arthropod herbivores, including insects and mites, causing damage to different parts of the plants during the season. Strawberry plantations also harbour beneficial arthropods such as predators, parasitoids and pollinators (e.g., predatory mites, lacewings, hoverflies,). Applications of beneficial fungi may enhance plant growth and decrease the incidence of specific arthropod pests, but their impact on entire arthropod communities is largely unknown. Two-season field trials were conducted in Denmark and Slovenia to study effects of the entomopathogenic Metarhizium brunneum, the mycoparasitic Clonostachys rosea, and arbuscular mycorrhizal biofertilizers, all fungi, on the main pest and beneficial arthropods in integrated (IPM) and organic (ORG) strawberry production systems. Soildeployed bioinocula had limited impact on aboveground arthropod assemblages, but treatment with the M. brunneum bioinoculum significantly increased the number of predators in the trials in Slovenia, while reducing arthropod abundance and diversity in Denmark. Agricultural management strongly affected arthropod communities, with ORG trials harbouring higher arthropod abundance and diversity compared to IPM, suggesting potential benefits of sustainable farming practices. The nuanced relationships among herbivores, beneficials, and pest infestations invites further investigation to unravel the underlying ecological mechanisms shaping pest dynamics in diverse agricultural landscapes.

The Japanese beetle, Popillia japonica Newman (Coleoptera, Scarabaeoidea), listed by the European Commission as one of the 20 priority plant pests, is reported for the first time in Slovenia. In the summer of 2024, eight beetles were found in funnel traps at two motorway service stations in central Slovenia: Lukovica South and Barje South. Visual inspections in the surrounding area revealed no infestation or damage to susceptible host plants. In addition to morphological identification, we confirmed the presence of P. japonica through molecular barcoding using the cytochrome c oxidase I (COI) gene. Based on its distribution in neighbouring northern Italy, the nearby outbreak and the isolated findings near the Slovenian border as well as the heavy freight traffic between northern Italy and Slovenia, a passive transport of P. japonica as a hitchhiker is very likely.

Summary Protein complexes from edible oyster mushrooms ( Pleurotus sp.) composed of pleurotolysin A2 (PlyA2) and pleurotolysin B (PlyB) exert toxicity in feeding tests against Colorado potato beetle (CPB) larvae, acting through the interaction with insect‐specific membrane sphingolipid. Here we present a new strategy for crop protection, based on in planta production of PlyA2/PlyB protein complexes, and we exemplify this strategy in construction of transgenic potato plants of cv Désirée. The transgenics in which PlyA2 was directed to the vacuole and PlyB to the endoplasmic reticulum are effectively protected from infestation by CPB larvae without impacting plant performance. These transgenic plants showed a pronounced effect on larval feeding rate, the larvae feeding on transgenic plants being on average five to six folds lighter than larvae feeding on controls. Further, only a fraction (11%–37%) of the larvae that fed on transgenic potato plants completed their life cycle and developed into adult beetles. Moreover, gene expression analysis of CPB larvae exposed to PlyA2/PlyB complexes revealed the response indicative of a general stress status of larvae and no evidence of possibility of developing resistance due to the functional inactivation of PlyA2/PlyB sphingolipid receptors.

The invasive pest, spotted wing drosophila (Drosophila suzukii (Matsumura, 1931) or SWD), damages various soft-skinned fruits, severely impacting orchards and vineyards economically. Current sorting practices in commercial production may overlook early-stage SWD infestations, as visible signs take a few days to appear. Our study focused on managing SWD infesting fruits (blueberry, cherry, and raspberry) without visible signs using an artificial atmosphere with elevated CO2 and low temperature. We hypothesized that these factors affect SWD survival and possibly interact, with potential variations among different soft- or stone-fruit species or varieties. High CO2 concentrations and cold storage both negatively affected SWD development. A 24-h 100% CO2 fumigation, without cold storage, significantly reduced SWD infestations in all 3 fruit species studied. On the other hand, 10% CO2 without cold storage did not cause a significant infestation reduction in cherries. Cold storage alone was too slow to be considered effective. Concurrent low-temperature treatment and CO2 treatment reduced the insecticidal efficacy of CO2 fumigation. Optimal fruit sanitation was achieved with a 3-h 100% CO2 treatment at ambient temperature before cold storage. Raspberries were the most suitable host for SWD development, with over a 5-fold higher SWD development compared to blueberries and over 50 times more than in cherries. We discussed the observed interactions between CO2 fumigation and chilling and suggested a simple postharvest SWD management protocol using optimal CO2 levels, exposure times, and chilling periods-achievable without complex equipment.

The objective of our research was to test hyperspectral imaging as a method for early detection and discrimination of biotic and abiotic stress in maize. We investigated the individual and combined effects of wireworm feeding and drought stress on leaf spectral responses and on various morphological and physiological traits of maize plants, selecting two hybrids with different tolerance to drought. Physiological parameters were determined at three time points (14, 21 and 28 days after adding wireworms and changing watering regime), along with hyperspectral imaging. Most of the differences in physiological characteristics between treatments were detected on day 21, when drought was the main cause of the negative physiological outcome, while the presence of wireworms only caused lower relative chlorophyll content, resulting in lower combined stress damage in some treatments. The morphological data showed greater wireworm damage to hybrid ZP341 and a greater negative effect of combined stress on hybrid FuturiXX. Hyperspectral imaging detected pest infestation and drought stress before they were detected by classical methods, with the highest overall accuracy on day 14 (84.7%) and the lowest on day 28 (67%). It can therefore be used as a method for early detection of wireworm infestation and/or drought in maize.

An aegerolysin protein ostreolysin A6 (OlyA6) binds to cholesterol-complexed sphingomyelin and can be used for specific labelling of lipid rafts. In addition, OlyA6 interacts with even higher affinity with ceramide phosphoethanolamine (CPE), a sphingolipid that dominates in invertebrate cell membranes. In the presence of pleurotolysin B, a protein bearing the membrane-attack complex/perforin domain, OlyA6 forms pores in insect midgut cell membranes and acts as a potent bioinsecticide. It has been shown that a point mutation of glutamate 69 to alanine (E69A) allows OlyA6 to bind to cholesterol-free sphingomyelin. Using artificial lipid membranes and mammalian MDCK cells, we show that this mutation significantly enhances the interaction of OlyA6 with sphingomyelin and CPE, and allows recognition of these sphingolipids even in the absence of cholesterol. Our results suggest that OlyA6 mutant E69A could serve as complementary tool to detect and study cholesterol-associated and free sphingomyelin or CPE in membranes. However, the mutation does not improve the membrane-permeabilizing activity after addition of pleurotolysin B, which was confirmed in toxicity tests on insect and mammalian cell lines, and on Colorado potato beetle larvae.

In recent decades, the spotted wing Drosophila (SWD) ( Drosophila suzukii ), an invasive pest, has caused a great deal of damage to fruit crops. There is therefore an urgent need to develop strategies to control the populations of this species. It has been found that the landscape context can buffer or increase the severity of pest outbreaks in agriculture, and it is important to understand how this process works in SWD for all crops. Given this background, we investigated the influence of forest on SWD populations in raspberry orchards and surrounding agricultural land. We selected 10 locations in the central part of Slovenia, five of which were closer than 200 m from the forest edge and five of which were more than 200 m from the forest edge. We collected SWD adults in three habitat types per location from the end of June until the end of October 2020. The results showed that forest harboured a larger SWD population than orchards and agricultural land. Over the season, the number of individuals increased exponentially over time, and the difference between forest and other habitat types increased. The distance from the forest had a negative effect on the abundance of SWD. There was a difference in abundance observed between males and females, with males being less abundant farther away from the forest than females. However, the distance from the forest only had a negative effect on the abundance of females in September. Based on the results, we propose potential measures for the control of SWD in raspberry orchards.

Plants respond to pest attack, among other mechanisms, by producing specific proteins with insecticidal properties. Proteins with toxic effects on insects have also been discovered in many other organisms, especially fungi and bacteria. Due to their biological function, insecticidal proteins represent an important potential in the development of more environmentally friendly plant protection methods. Increasing knowledge about the mode of action of insecticidal proteins and the identification of genes encoding their synthesis enable the breeding of transgenic plants resistant to insect pests and the development of new bioinsecticidal agents. The Colorado potato beetle (Leptinotarsa decemlineata) is one of the most important pests of potato, so the study of such control methods is crucial for the development of sustainable integrated pest management strategies of potato. This review highlights the properties of some groups of insecticidal proteins and their modes of action, and summarizes examples of studies of their use for the control of Colorado potato beetle.

The use of entomopathogenic fungi represents one of the most important non-chemical alternatives for pest control in crop production. In addition to their pathogenicity to arthropods, they have many other important effects that favor their use in biological control. They live in plants as endophytes and have an inhibitory effect on plant pathogens. They inhabit the rhizosphere of many plants in natural and agricultural ecosystems and have a stimulatory effect on their growth and development. These recently acquired ecological functions are not yet fully understood, but point to the broader potential of using entomopathogenic endophytic fungi in crop production, not only as biopesticides but also as mycofungicides and growth stimulants (biostimulants). To achieve the full potential of entomopathogenic endophytic fungi in daily agricultural practice, practical application should be considered in the development of commercial products and the application techniques of entomopathogenic endophytic fungi that allow successful colonization of plants should be considered.

The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera, Chrysomelidae), is an important insect pest of maize in North America and Central and Eastern Europe. In Central Europe, the larvae emerge in May and its three instars feed intensively on maize roots in June, causing plant lodging that leads to a loss of economic yield. A three-year field experiment (2016–2018) was conducted to compare the effectiveness i) of soil-applied granular insecticide based on the active ingredient tefluthrin, ii) of maize seeds dressed with thiacloprid, and iii) entomopathogenic nematodes Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae, product Dianem) against WCR larvae. An additional treatment with alcohol ethoxylate (i.e., soil conditioner) mixed with entomopathogenic nematodes was performed in 2017 and 2018 to check for any increase of entomopathogenic nematodes’ effectiveness. Field tests were carried out in two fields infested naturally with a WCR pest population, one in Bučečovci (Eastern Slovenia) and the other in Šmartno pri Cerkljah (northern Slovenia), exhibiting dissimilar pedo-climatic conditions and soil pest densities. The treatments were performed in five replicates per experiment in each year. The efficacy of the treatments was very similar at both locations, despite the approximately five-fold lower WCR soil pest densities in northern than in eastern Slovenia, as well as being constant over time. The largest number of WCR beetles was observed in the negative control, followed by that of beetles subjected to thiacloprid treatment (insignificant decrease taking into account the entire three-year dataset). Treatments with tefluthrin (44.1 ± 11.7%), H. bacteriophora (46.2 ± 7.4%), and H. bacteriophora + alcohol ethoxylate (49.2 ± 1.8%) significantly decreased the numbers of emerging beetles. Treatments of thiacloprid, H. bacteriophora, and H. bacteriophora + alcohol ethoxylate additionally led to significantly increased maize plant weights. Furthermore, entomopathogenic nematodes were able to persist in maize fields for almost five months at both experimental locations in silty and sandy loam soils. It was concluded that the control of WCR larvae in maize using the entomopathogenic nematode H. bacteriophora is as effective as a tefluthrin treatment, and could thus offer a sustainable Diabrotica v. virgifera biological control management option in Europe.

The Spotted-wing drosophila (SWD), Drosophila suzukii (Matsumura, 1931) (Diptera, Drosophilidae) was recorded for the first time in Slovenia in autumn 2010. Shortly thereafter, it turned out to be one of the most important insect pests of soft and stone fruit in Slovenia and elsewhere. Within the expert work in the field of plant protection, more precisely within task inventarisation of beneficial organisms for biological control, the presence of indigenous D. suzukii parasitoids was investigated in 2018. Sentinel traps baited with D. suzukii larvae and pupae in banana slices enriched with artificial food medium for drosophilids were used for inventorying D. suzukii parasitoids in raspberries. The pupal parasitoid Trichopria drosophilae (Perkins, 1910) (Hymenoptera: Diapriidae) and the larval parasitoid Leptopilina heterotoma (Thompson, 1862) (Hymenoptera: Figitidae) were recorded parasitizing D. suzukiifor the first time in Slovenia in August 2018 in Central Slovenia (Ljubljana).