Search Results (8)

(1) Background: Oat (Avena sativa L.) is a crop that is widely used in human nutrition, while it also plays an important role in animal husbandry as a high-quality forage crop. However, this crop is particularly susceptible to combined biotic stressors, including insect pests (Agriotes lineatus) and fungal infections (Fusarium spp.). These stresses act synergistically: root damage caused by wireworms increases the plant’s susceptibility to fungal infection, while pathogens further limit nutrient uptake and root system development. In recent years, the reduced efficacy of chemical pesticides against both insect pests and fungal pathogens has highlighted the need for alternative strategies in oat protection, leading to an increased focus on developing bacterial bio-inoculants as sustainable and effective biocontrol agents. (2) Methods: This study aimed to identify bacterial strains capable of suppressing wireworms (Agriotes lineatus) and Fusarium spp. in oats, while simultaneously promoting plant growth. Bacterial isolates were screened for key Plant Growth Promoting (PGP) and biocontrol traits, including IAA and siderophore production, phosphate solubilization, and the presence of toxin- and antibiotic-coding genes. (3) Results: The highest insecticidal effect against wireworms was recorded for Bacillus velezensis BHC 3.1 (63.33%), while this isolate also suppressed the growth of F. proliferatum for 59%, F. oxysporum for 65%, F. poae for 71%, and F. graminearum for 15%. The most effective Bacillus strains (with insecticidal and antifungal activity) were identified and tested in two pot experiments, where their ability to enhance plant growth in the presence of insects and fungi was evaluated under semi-controlled conditions. An increase in plant biomass, grain yield, and nitrogen content was observed in oat inoculated with B. velezensis BHC 3.1 and B. thuringiensis BHC 2.4. (4) Conclusions: These results demonstrate the strong potential of both strains as multifunctional bio-inoculants for enhancing oat growth and mitigating the adverse effects of wireworm damage and Fusarium infection. Full article

Between 2023 and 2025, we conducted experiments at the Laboratory Field of the Bio-technical Faculty in Ljubljana to study alternative methods for controlling wireworms in potato fields. The trials were arranged in three blocks with five first-order (Brassica carinata, Brassica juncea, Nemakil 330, Rasti Soil Tonic G, positive control) and five second-order treatments (entomopathogenic nematodes, entomopathogenic fungi, zeolite combined with half-doses of these products, positive control with tefluthrin, and negative control), giving twenty-five treatments per block. Foliar pests and diseases were managed with contact plant protection products. We measured total tuber yield and divided it into three size classes, then assessed wireworm damage (holes per tuber). The purpose of the soil excavations in the first-order treatments was to verify the abundance of wireworms in the soil. Most combinations reduced wireworm abundance. The lowest tuber damage comparable to the positive control occurred when using zeolite with half-doses of entomopathogenic nematodes and fungi. The highest yields across all three weather-distinct years resulted from combining Rasti Soil Tonic with zeolite and half-dose entomopathogenic products. Although Nemakil 330 increased soil phosphorus, it neither improved yield nor reduced wireworm damage. Overall, the tested environmentally acceptable methods show promising insecticidal potential for sustainable wireworm control in potatoes. Full article

Wireworms (Agriotes spp., Coleoptera, Elateridae) are a major threat to potatoes, as are the current commercial standards for assessing potato damage. To reduce wireworm impacts on potato crops and comply with IPM legislation, we started research to assess the potential for new Italian 4x-breeding clones to reduce wireworm feeding on daughter tubers. Two sets of trials were carried out over a six-year period (2018–2023): in-field and in semi-natural conditions, with pots used to introduce a set number of reared wireworms. In the field trials, the varieties were planted in 4.8 × 9–12 m plots in a randomized-block layout with at least three replications. The same wireworm damage assessment was used for both sets of trials. The assessment involved counting all the erosions/scars caused by wireworm feeding activity. The prevalent wireworm species studied was Agriotes sordidus. Both sets of trials showed that some 4x-breeding clones were tolerant to wireworm attacks. The percentages of tubers damaged (any symptom) or with at least one ordinary/large hole was up to five times lower than in the commercial varieties. Glycoalkaloids and the caffeic acid content in tubers are considered to be the main cause of lower appetibility to wireworms. Full article

Low-cost monitoring tools are needed to implement IPM in arable crops. YATLORf (Yf) traps baited with respective synthetic pheromone lures have proven to be a reliable tool for monitoring Agriotes spp., Europe’s most harmful soil pests. To optimize Yf use, we studied the effect of lure position in the trap and crop density on trap performance. Yf management detail was studied between 2000–2003 and 2014–2016 in various countries, with the traps being arranged in blocks. Each block contained one trap per treatment (i.e., lure position) under study. It was ascertained that lure attractant capacity can vary greatly with the lure’s position in the trap and the extent of vegetation. Information for making practical decisions is given. The ‘low’ lure position is suitable for all species in all field conditions, and is the best choice for A. brevis. Lures for A. brevis and A. lineatus need to be placed in the low position when the field has no or sparse vegetation cover. The ‘high’ lure position is unsuitable for A. brevis and A. obscurus, and should be considered for some species only. There are no restrictions on position for catching A. sordidus, i.e., any position is suitable. Dense vegetation (e.g., wheat) reduced the Yf trap’s potential for catching A. sordidus. Placing the trap just outside the field, or in a nearby field with bare/sparse vegetation, maintained the maximum catching potential. Vegetation density also influenced beetle sex ratio, with A. brevis and A. sordidus females always found in traps placed in fields with bare or low-density vegetation. Our findings have made it possible to obtain consistent monitoring outputs and to begin studies on multi-baiting the same trap, which can significantly reduce monitoring costs. Full article

Wireworms (Coleoptera: Elateridae) are common insect pests that attack a wide range of economically important crops including potatoes. The control of wireworms is of prime importance in potato production due to the potential damage of the larvae to tuber quantity and quality. Chemical insecticides, the main control strategy against wireworms, generally fail to provide satisfactory control due to the lack of available chemicals and the soil-dwelling habits of the larvae. In the last decades, new eco-friendly concepts have emerged in the sustainable control of wireworms, one of which is entomopathogenic nematodes (EPNs). EPNs are soil-inhabitant organisms and represent an ecological approach to controlling a great variety of soil-dwelling insect pests. In this study, the susceptibility of Agriotes sputator Linnaeus and A. rufipalpis Brullé larvae, the most common wireworm species in potato cultivation in Türkiye, to native EPN strains [Steinernema carpocapsae (Sc_BL22), S. feltiae (Sf_BL24 and Sf_KAY4), and Heterorhabditis bacteriophora (Hb_KAY10 and Hb_AF12)] were evaluated at two temperatures (25 and 30 °C) in pot experiments. Heterorhabditis bacteriophora Hb_AF12 was the most effective strain at 30 °C six days post-inoculation and caused 37.5% mortality to A. rufipalpis larvae. Agriotes sputator larvae were more susceptible to tested EPNs at the same exposure time, and 50% mortality was achieved by two EPNs species, Hb_AF12 and Sc_BL22. All EPN species/strains induced mortality over 70% to both wireworm species at both temperatures at 100 IJs/cm², 18 days post-treatment. The results suggest that tested EPN species/strains have great potential in the control of A. sputator and A. rufipalpis larvae. Full article

Wireworms are yellowish soil-dwelling larvae that damage a wide range of arable crops. The most common wireworms found in European cultivated fields (except for the Caucasus) belong to the genus Agriotes (Coleoptera: Elateridae). In several European countries, environment-impacting insecticides are applied on a prophylactic basis to control them. However, before any treatment can be applied, European legislation requires that an assessment is done when pest population levels exceed a damage threshold. The threshold substantially depends on wireworm species, thus quick reliable larval identification is needed to implement the appropriate integrated pest management practices. Furthermore, research into non-chemical strategies involves carrying out tests with live and identified wireworms. Thus, thousands of wireworms were observed in a bid to identify live larvae so that larval density could be assessed and compared with species-specific thresholds before sowing, and laboratory experiments were carried out. This work led to a horizontal identification table that allows for quick and accurate identification of live larvae. This key, unlike traditional dichotomous keys, simultaneously considers a set of multiple discriminating morphological characters in order of stability. The key can be reliably used by less experienced users and, once minimum familiarity is acquired, most larvae can be identified rapidly, with high precision. Full article

Plants are challenged by both above- and belowground herbivores which may indirectly interact with each other via herbivore-induced changes in plant traits; however, little is known about how genetic variation of the host plant shapes such interactions. We used two genotypes (M4 and E9) of Solanum dulcamara (Solanaceae) with or without previous experience of aboveground herbivory by Spodoptera exigua (Noctuidae) to quantify its effects on subsequent root herbivory by Agriotes spp. (Elateridae). In the genotype M4, due to the aboveground herbivory, shoot and root biomass was significantly decreased, roots had a lower C/N ratio and contained significantly higher levels of proteins, while the genotype E9 was not affected. However, aboveground herbivory had no effects on weight gain or mortality of the belowground herbivores. Root herbivory by Agriotes increased the nitrogen concentration in the roots of M4 plants leading to a higher weight gain of conspecific larvae. Also, in feeding bioassays, Agriotes larvae tended to prefer roots of M4 over E9, irrespective of the aboveground herbivore treatment. Fourier-Transform Infrared Spectroscopy (FT-IR) documented differences in metabolic profiles of the two plant genotypes and of the roots of M4 plants after aboveground herbivory. Together, these results demonstrate that previous aboveground herbivory can have genotype-specific effects on quantitative and qualitative root traits. This may have consequences for belowground interactions, although generalist root herbivores might not be affected when the root biomass offered is still sufficient for growth and survival. Full article

Wireworms (Coleoptera: Elateridae) are important soil dwelling pests worldwide causing yield losses in many crops. The progressive restrictions in the matter of efficient synthetic chemicals for health and environmental care brought out the need for alternative management techniques. This paper summarizes the main potential tools that have been studied up to now and that could be applied together in integrated pest management systems and suggests guidelines for future research. Full article