Tebuconazole + fluopyram is a new binary mixture fungicide product that is widely used to control many plant fungal pathogens and nematodes in several agricultural crops worldwide, including Egypt. However, there is a lack of information about their toxicological effects on honeybees (Apis mellifera L.). In the current study, the lethal and sub-lethal toxic effects of mixture tebuconazole + fluopyram were examined on A. mellifera workers. Tebuconazole + fluopyram exhibited low acute toxicity to A. mellifera foragers (the 96-h LC₅₀ value was 1.389 mg a.i. ml^–1). Sub-lethal effects of tebuconazole + fluopyram on survival, body weight, food consumption and antioxidant defenses of A. mellifera were determined by chronic oral exposure of A. mellifera workers to sugar syrup which contained two sublethal concentrations of the fungicide, 0.139 mg ml^–1 (1/10 of 96-h LC₅₀) and 0.278 mg ml^–1 (1/5 of 96-h LC₅₀), along with clear sugar syrup as a control for 18 days. Honeybees exposed to both sublethal concentrations of tebuconazole + fluopyram showed a significant decrease in the bees’ survivability and dry body weight. Sugar syrup and pollen consumption by the exposed A. mellifera were relatively less than by the controls. Tebuconazole + fluopyram also induced disruptions in the enzymatic antioxidant and detoxification defense systems in bees, indicating the presence of oxidative stress. Fungicide exposure elicited a significant depletion in catalase and superoxide dismutase activities and a significant elevation in glutathione and malondialdehyde levels in bees, indicating lipid peroxidation. This is the first study indicating the harmful impacts of tebuconazole + fluopyram on honeybee health.

Sugar beet leaves with dark brown to blackish, necrotic lesions were found in a grower’s field in Casselton, North Dakota, USA in August 2021. Morphological features of the isolates obtained in growth media from the diseased samples were observed and documented. The pathogenicity of the randomly selected isolates developed identical disease symptoms on the inoculated leaves. Molecular characterization of the isolates was conducted by identifying homologies with sequences of the internal transcribed spacer, the largest subunit of RNA polymerase II (rpb2), β-tubulin (β-tub), calmodulin (CaM), and plasma membrane ATPase (Pma1) genes followed by multilocus phylogenic analyses. Based on morphological characteristics, pathogenicity, and molecular analyses, the causal organism was identified as Colletotrichum spaethianum. This is the first report of C. spaethianum causing leaf spot on sugar beet in North Dakota, USA. The report will help growers design an effective disease management for a novel pathogen in sugar beet in the Red River Valley of Minnesota and North Dakota, USA.

Ground cover plants in orchards can effectively improve soil quality. One factor determin­ing soil health is the presence of fauna, including mesofauna, which play a crucial role in soil ecosystems. However, the relationship between ground cover and Collembola assemblages in orchards remains underexplored. This study investigated how different ground cover plants sown in rows of apple trees influence the abundance and diversity of Collembola. Conducted at the Research Station of Wrocław University of Environmental and Life Sciences, Poland, the experiment utilized three cover species: Tagetes patula, Festuca ovina, and Agrostis capillaris, with fallow plots serving as control samples. Soil samples were collected over 2 years (2015–2016) to assess springtails richness and species composition. Results indicated that springtails were significantly more abundant in soils managed with ground cover plants than in conventionally managed fallow stands. Notably, the highest mean Collembola numbers were recorded in strips planted with T. patula and F. ovina. The springtail communities were primarily dominant in each of the treatments by two eudaphic species, Mesaphorura macrochaeta and Hypogastrura assimilis. These findings underscore the importance of cover crops in sustainable agriculture by reducing herbicide reliance, enhancing soil aeration, improving soil fertility through organic matter, and fostering biodiversity of soil biota.

Cannabis aphid Phorodon (Diphorodon) cannabis Passerini 1860 is an economically impor­tant pest of oil hemp (Cannabis sativa L.) and is controlled by insecticides. Oil hemp crops are treated with herbicides, which are non-target pesticides for aphids but may also affect aphid populations. Such ecological implications of plant protection products are rarely in­vestigated. The aim of the present research was to better understand plant ‒ aphid ‒ her­bicide interactions, specifically, changes of fatty acids (FAs) in leaves, caused by cannabis aphids and a common herbicide used in hemp fields.

Of 21 FAs detected in hemp leaves, aphid feeding significantly increased the amounts of myristic and oleic acids and decreased the content of α-linolenic acid. This effect was found when aphids fed on hemp plants and especially when plants were treated with an herbicide containing quizalofop-P-tefuryl. This compound on its own did not affect the FA composi­tion. In spite of the extremely high increase of myristic acid (7- to 9-fold, depending on the experiment variant), which could cause the repellent effect in hemp plants, the decreased amount of α-linolenic acid, the precursor of jasmonic acid may have helped aphids to ma­nipulate the jasmonate signaling pathway involved in plant defense to herbivory enabling their continued feeding on hemp. This study revealed the importance of FAs in plant de­fense as well as the side effects of non-target plant protection products. Future pest man­agement should take into account the complex interactions between crop plants, their pests and non-target effects of chemicals used in real field situations.

Plasmodiophora brassicae is an obligate parasite and a natural soil inhabitant that causes clubroot, a disease with significant economic impact in plants of the Brassicaceae family. This pathology is conditioned by plant/host interactions, edaphoclimatic variables, and mechanisms of inoculum dispersal. However, the epidemiology of this pathogen is not well understood, thereby limiting its incorporation into integrated disease management strategies (IDM). The objective of this work was to adjust a mesoscale risk and prognostic model of P. brassicae based on edaphoclimatic factors and potential dispersal mechanisms in brassica-producing areas in Colombia. The presence and inoculum density of the pathogen were determined by visual inspection of symptoms and quantification by qPCR of soil samples in a total of 127 plots located in regions with the highest production of species from the Brassicaceae family. In addition, an edaphoclimatic characterization was carried out based on field data and secondary information by web scraping using freely available databases. The forecast models were determined by fitting a Generalized Linear Model (GLM) using the logit and inverse link functions for binomial and gamma distributions, respectively. The meso- and macroscale spatial risk model was developed under point pattern approaches (Kernel density model and ecological niche model (ENM). The different epidemiological analysis approaches used suggest that P. brassicae presents a high risk in areas with host presence and conducive edaphoclimatic characteristics, indicating the need to carry out epidemiological surveillance, reduce the dispersion of infested soil, and implement P. brassicae exclusion methods.

Potato (Solanum tuberosum) is a globally important crop, but its production is often threatened by pectinolytic bacteria of genus Pectobacterium and Dickeya, including Pectobacte­rium brasiliense (Pcb), and Dickeya solani (Ds), which cause two diseases, soft rot of potato tubers and blackleg of potato plants. These pathogens cause a reduction of potato yield, and significant yield losses due to tuber rot in storage. Currently, there are no effective chemical solutions to control these bacterial pathogens. This study aimed to investigate the effect of tuber greening, a process that significantly increases the content of glycoalkaloids (GAs), on the susceptibility of the potato cultivar Tajfun to infection by Pcb and Ds. Tubers were exposed to continuous artificial light for 2 weeks to induce greening. Control tubers were kept in the dark under the same environmental conditions. Then, tubers were infiltrated with Pcb and Ds under low pressure to ensure efficient bacterial penetration and planted in pots under controlled conditions. After 3 weeks phenotypic symptoms of bacterial in­fection such as wilting, overall plant vitality and stem necrosis were determined. Results showed a significant reduction in Ds infection in greened tubers compared to non-greened controls, supporting the hypothesis that greening which increases GAs levels, enhances resistance to bacterial pathogens. The response to Pcb was more variable, with some plants grown from greened tubers still exhibiting high levels of infection, suggesting that while greening may reduce susceptibility, the greater aggressiveness of Pcb may limit the pro­tective effects of greening. In conclusion, the present study showed that tuber greening could be an effective non-chemical method for controlling blackleg, particularly against Ds. However, the variable response to Pcb indicates that additional strategies are needed. Future research should focus on integrating GAs-based defenses with potato cultivars that exhibit stronger resistance to pectinolytic bacteria for improved management of blackleg.