Search Results (177)

Naturally abundant endophytes colonize plants internally without causing harm to their host plants. Endophytes are likely to occupy the same ecological niches as phytopathogens and thus have a high potential to be effective biological control agents. Their demonstrated ability to suppress more than one plant pathogen suggests that they can offer a viable alternative to chemical fungicides and a strategy for decreasing the inoculum potential of soil-borne pathogens. Some biocontrol endophytes are also known to improve soil health and the overall health of plants. However, the results in greenhouse studies do not always translate to consistent field efficacy. In this study, the efficacy of three endophytic bacterial isolates (PRT (Bacillus subtilis), PSL (Bacillus amyloliquefaciens), and IMC8 (Bacillus thuringiesis) were evaluated against Phytophthora capsici in a field environment and compared with two commercial biological fungicides, Serenade^® (Bayer Crop Science, St Louis MO, USA) and Double Nickel^® (Certis Biologicals, Columbia, MO, USA), and water control. Plants were inoculated with the bacteria strains using seed treatment for early plant colonization before transplanting to a field infested with P. capsici. Treatments with commercial bio-fungicides followed label recommendations. Data on plant growth vigor, disease severity, number of fruits, fruit size, total yield per plant, and percent of diseased fruits displayed significant differences between the bacteria treatments. While PRT was the best treatment for most traits, followed by PSL on pepper, PSL and Double Nickel were the best treatments on tomatoes. IMC8 was best for plant vigor and larger fruit size, but with fewer fruits per plant on both crops. This study suggests bacterial isolates PRT, PSL, and IMC8 can provide additional products for growth promotion and P. capsici disease management in pepper and tomatoes. Full article

The increasing global movement of plant material and the complexity of viral communities associated with cultivated crops complicate routine plant virus diagnostics. High-throughput sequencing (HTS) has therefore become an important tool for the comprehensive characterization of plant viromes. In this study, symptomatic pepper (Capsicum annuum) samples submitted to our laboratory between 2020 and 2025 were investigated using HTS following unsuccessful routine diagnostic assays, despite the presence of virus-like symptoms. Virome analysis revealed the presence of multiple viruses with distinct biological characteristics. Eggplant mottled dwarf virus (EMDV) sequences were identified, representing, to our knowledge, the first sequence data from Hungary. In addition, sequences related to tobacco vein clearing virus (TVCV) showed highest similarity to endogenous viral element present in Capsicum annuum genome assemblies. Persistent viruses, including bell pepper alphaendornavirus (BPEV) and pepper cryptic virus 2 (PCV2), were also detected. These findings demonstrate the complex viral communities associated with cultivated pepper and highlight the limitations of strictly targeted diagnostic approaches. The results emphasize the value of HTS for comprehensive virome characterization in horticultural crops. Full article

The early and accurate detection of plant diseases is essential for crop management and agricultural loss control, especially under resource limitations. We propose an optimized YOLO11n architecture, designated as YOLO11_Opt, targeting real-time inference on low-cost embedded systems. The model is computationally efficient through the selective narrowing of its width and depth, while performing competitively in two-class object recognition tasks. Pepper leaves were chosen as the materials for study. Three methods of quantization (FP32, FP16, and INT8) were investigated. After running the experiments, the results showed that YOLO11_Opt greatly reduces the computational complexity: the complexity decreased from 6.3 GFLOPS and 2.58 million parameters in the typical YOLO11n model to a very small 0.5 GFLOPS and 0.33 million parameters, while maintaining competitive detection capabilities. The improved FP32 model has a mAP (0.5:0.95) of 0.913 and a precision of 0.991, while the old version has 0.961 mAP and 0.996 precision. Lastly, implementations on embedded hardware prove that the method is feasible: the detection accuracy of the system in live classification is around 92% with Raspberry Pi 4 and 94% with NVIDIA Jetson Nano, with inference times of as little as 1.9 ms on NVIDIA Jetson Nano and 8.3 ms on Raspberry Pi 4. Thus, YOLO11_Opt demonstrates significant potential as a reliable, high-performance, low-cost solution to identifying plant diseases on devices in precision agriculture. Full article

This study evaluated the effects of thermocomposting followed by vermicomposting on the physicochemical properties of insect frass and its suitability as a germination and growth substrate for kale, tomato, and bell pepper. Vermicomposting improved frass stability by reducing pH, electrical conductivity, carbon content, and the C/N ratio, while increasing total nitrogen, cation exchange capacity, and calcium and magnesium availability, indicating enhanced maturity and nutrient retention. Peat–frass mixtures (20–100%), increased pH from acidic conditions in the control to near neutral in 100% frass and raised electrical conductivity from 0.67 dS m⁻¹ to the highest values in the pure frass treatment. Tomato seedlings exhibited strong tolerance and enhanced growth at all frass proportions, with seedling heights exceeding 33 cm compared with the control. Kale showed optimal growth at 20–60% frass, while 80–100% reduced early development. In bell pepper, emergence declined at high frass proportions, although seedlings grown with ≥40% frass reached heights of approximately 8.3–8.6 cm. Vermicomposted frass also influenced plant metabolism, increasing flavonoid accumulation and modifying antioxidant activity. These findings demonstrate that stabilized frass can serve as a sustainable substrate component, contributing to organic waste valorization and improved seedling production when applied at crop-specific proportions. Full article

Global vegetable production exceeded 1.2 billion tons in 2022, with bell pepper (Capsicum annuum) accounting for 37 million tons, a crop of high value due to its versatility, commercial demand, and nutritional properties. In the Dominican Republic, greenhouse vegetable production has experienced accelerated growth over the last 23 years, reaching over 10 million m² of infrastructure and increasing pepper production from 9122 to 32,000 tons. However, limitations in technical information regarding nutritional management and substrate use persist, despite the extensive empirical experience of producers and technicians. This study evaluated the effect of three fertigation programs (low, medium, and high doses: FP1, FP2, and FP3) and three substrates (carbonized rice husk- CRH, coconut fiber-CF, and a 1:1 Mix) on 180 plants grown for 141 days in a greenhouse, using a completely randomized split-plot design. Growth, physiological, quality, and yield indicators were measured. Principal Component Analysis (PCA) explained 88% of the variability, showing that FP2 and FP3, combined with BRH and the 1:1 Mix, generated greater plant height, stem diameter, chlorophyll content, and canopy development, while FP1 and CF were associated with lower performance. Regarding fruit quality, the BRH and 1:1 Mix substrates yielded higher values for length, width, and weight, whereas °Brix content responded primarily to fertigation doses. Total yield confirmed this pattern, highlighting FP3–BRH as the best combination evaluated and FP1–CF as the one with the lowest productivity. Full article

This study evaluated the energy-dependent effects of pulsed electric field (PEF) treatment on the physicochemical properties, bioactive compounds, antioxidant activity, and microstructure of red bell pepper (Capsicum annuum L.). Red bell pepper tissue was treated at specific energy inputs ranging from 1 to 10 kJ/kg and compared with a fresh (untreated sample). The cell disintegration index (CDI) increased progressively with PEF energy, confirming enhanced membrane permeabilization and structural disruption. Structural analyses (SEM and micro-CT) confirmed the formation of pores and interconnected channels, particularly at moderate and high energies. PEF treatment caused a decrease in total polyphenols and flavonoids, whereas vitamin C and total carotenoid contents increased at intermediate energies. Antioxidant activity (ABTS, DPPH, FRAP) declined overall but remained at comparable levels for mild PEF exposure. A significant reduction in firmness was observed (from 17% to 27% compared with the untreated control), and color changes were dependent on the energy input, while microstructural degradation intensified as the energy level approached 10 kJ/kg. PEF treatment improved microbial stability, resulting in a measurable reduction in total viable counts and yeast and mold counts, particularly at higher energy inputs. FTIR, TGA, and NMR data confirmed molecular alterations without degradation of major components. Multivariate analysis (dendrogram, PCA) distinguished four characteristic response groups: fresh, low-energy (1–2 kJ/kg), moderate-energy (4–5 kJ/kg), and high-energy (10 kJ/kg). PEF treatment selectively modified red bell pepper tissue, enhancing permeabilization and carotenoid/vitamin C release while preserving visual quality at mild–moderate energies. These results demonstrate the potential of PEF as a nonthermal technique for tailoring the structural and functional properties of plant-based products. Full article

Peppers are of substantial economic importance and hold a prominent position among vegetables rich in health-promoting compounds, which drives continuous efforts to develop improved cultivation strategies. The study aimed to determine the effects of substrate type and depolymerized chitosan on the physiological parameters, the chemical composition of leaves and fruits, and the yield of two bell pepper cultivars: ‘Marta Polka’ and ‘Oda’. The plants were grown in a 100% peat substrate and in a mixture of peat, wood fiber (Pinus sylvestris), and green compost (2:1:1 v/v/v), with or without drenching with a solution of depolymerized chitosan. Results indicated that the growing medium, chitosan application, cultivar type, and their interactions altered several physiological, morphological, and biochemical traits. The highest total fruit weight fresh (471.23 g plant⁻¹) was obtained for the ‘Marta Polka’ cultivar grown in peat drenched with chitosan, whereas the lowest (192.02 g plant⁻¹) was recorded for ‘Oda’ grown in a substrate mix without the biostimulant. Net CO₂ assimilation rate, stomatal conductance, fresh weight of fruit, and antioxidant activity (ABTS and FRAP assays) were improved in the ‘Oda’ cultivar grown in the substrate mix and treated with depolymerized chitosan compared with plants grown in 100% peat without chitosan. The ‘Marta Polka’ plants grown in the substrate mix and treated with chitosan had a higher net CO₂ assimilation rate, photosynthetic water-use efficiency, total free amino acid content, and antioxidant activity (FRAP assay) than those grown in peat alone and not treated with the biostimulant. The results demonstrate that both substrate composition and the response to depolymerized chitosan are cultivar-specific, and that wood fiber and compost can serve as ecological alternatives to peat, enhancing overall pepper fruit quality. Full article

This study provides a comprehensive assessment of the effect of direct (probe) and indirect (bath) ultrasound treatments on the physicochemical and structural properties of red bell pepper (Capsicum annuum L.) tissue. Ultrasound was applied under controlled conditions to induce structural modification without excessive thermal or mechanical damage. The treated samples were evaluated using chemical (polyphenols, flavonoids, carotenoids, vitamin C, sugars), microbiological (total viable count (TVC) and total yeast and mold count (TYM)), spectroscopic (FTIR, NMR), thermal (TGA), and microscopic (SEM, micro-CT) analyses. Both ultrasound modes affected the tissue, but their effects differed in intensity and character. Direct ultrasound caused stronger cavitation and mechanical stress, resulting in greater cell wall disruption, higher permeability, and enhanced release of bioactive compounds such as polyphenols, vitamin C and antioxidants from the tissue matrix to the surroundings. Indirect ultrasound acted more gently, preserving cellular integrity and sugar profile while moderately increasing antioxidant activity. Cluster and correlation analyses confirmed that ultrasound mode was the main factor differentiating the samples. Short-term direct sonication enhanced the release of antioxidant compounds, whereas prolonged exposure led to their degradation, resulting in an overall decline in antioxidant capacity, and indirect ultrasound better preserved texture and sugar composition. This demonstrates that ultrasound mode and duration can be tailored to balance tissue integrity and enhance bioactive compounds in plant-based materials. Full article

Plant growth-promoting bacteria (PGPB) can act as biostimulants, improving the growth of plants in sustainable agriculture systems that seek to reduce synthetic agrochemical input. Bacteria present in seeds are closely associated with vertical transmission and thus represent a potential trove of biostimulants. Capsicum species are notable for producing capsaicin, a compound with antimicrobial activity that may influence microbial communities associated with pepper fruits and seeds. Using Luria–Bertani (LB) media infused with capsaicin, we isolated bacteria from bell peppers, jalapeno peppers, and habanero peppers, which we verified to have different levels of capsaicin through high-performance liquid chromatography with ultraviolet detection (HPLC-UV). Minimum inhibitory concentration (MIC) assays indicated that the capsaicin resistance of isolated bacteria did not correlate with the pungency level of the host pepper variety. Of the total isolated bacteria, four showed promise as plant growth promoters; two belong to the genera Pseudomonas, one Agrobacterium, and one Bacillus. Our isolates tested positively for potassium and phosphate solubilization, urease production, and indole-3-acetic acid (IAA) phytohormone production. Inoculation of these bacteria into surface-sterilized red clover (Trifolium pratense) and Kentucky bluegrass (Poa pratensis) showed significant improvements in germination rate, seedling root length, and seedling shoot height. These results show that the pungency of peppers does not influence the capsaicin resistance of isolated bacteria. Additionally, seedborne PGPB have the potential for plant growth improvement through various mechanisms, reducing the need for synthetic chemicals. Full article

The diverse phytochemical profiles of host plants can significantly influence their interactions with herbivores and natural enemies. This study investigated the ‘bottom-up’ effects of several bell pepper and eggplant cultivars on the development, reproduction, and survival of the green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), and its predators, Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae) and Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae). We analyzed the leaves of each cultivar for levels of total flavonoids, phenols, anthocyanins, and key defensive enzymes. The eggplant cultivar ‘Longo’ exhibited the highest concentration of secondary metabolites. Aphid populations reared on this cultivar’s leaves showed a slower growth rate compared to those on other cultivars. Conversely, predators fed on these aphids demonstrated higher rates of population growth and produced more offspring. Accordingly, the intrinsic rate of natural increase (r) was lower for aphids feeding on ‘Longo’, but significantly higher for both A. aphidimyza and C. carnea when fed those aphids. These results demonstrate that elevated secondary metabolites on ‘Longo’ suppress the performance of M. persicae while enhancing predator efficiency, thereby providing a phytochemical-based approach that can serve as an effective component of integrated pest management (IPM) programs. Full article

This study investigates the potential to transform plant-based waste into a sustainable resource for animal feed through dehydration. Currently, research on the drying performance of decayed plant tissues remains scarce. To address this gap, we explored the use of a thermogravimetric analyzer (TGA) as a precisely controlled convective drying method to evaluate the drying performance of decayed strawberries (ST) and bell peppers (BP), as models for high- and low-porous structures, respectively. Drying curves, moisture diffusivity, yeast and mold load, and microstructure of decayed plant tissues were evaluated. Our results showed that decayed BP and ST tissues dried up to 22% faster than fresh tissues, with a higher effective moisture diffusivity. Significantly higher yeast and mold counts (log CFU/g) were detected in decayed tissues, resulting in softening and deterioration of the plant tissues. Significant differences were found in the effective moisture diffusivity (D_eff) of bell pepper (BP) and strawberry (ST), with ST tissues exhibiting a greater degree of decay. The microstructural changes in the cell wall caused by decay influenced drying performance and mass transport kinetics, indicating that drying decayed plant tissues is less time-consuming than drying fresh food. These findings offer critical insights for designing drying processes that enhance the value of food waste. Full article

Red bell pepper (Capsicum annuum L.) is a valuable source of health-promoting phytochemicals and essential minerals. This study investigated the impact of using geothermal mineral water versus tap water as the fermentation medium on the nutritional, physicochemical, and sensory properties of two red bell peppers (cultivars ‘Yecla F₁’ and ‘Salomon F₁’). The results showed that fermentation caused a significant decrease in the content of L-ascorbic acid (by 30–50%), carotenoids (~30%) and polyphenols (by 25–30%), with lower nutrient losses observed in peppers fermented with geothermal water. In addition, fermentation with geothermal water increased the calcium, magnesium, and potassium contents of the peppers compared to tap water. Sensory analysis showed that the pepper cultivars had a greater impact on the overall sensory quality than the fermentation medium or the evaluation time, although geothermal water had a positive effect on the texture of the fermented peppers. These results suggest that geothermal water may be a beneficial alternative to traditional water sources in vegetable fermentation, improving both the nutritional and sensory properties of the final product. Full article

Organic fertilization management for vegetable transplant production is challenging to growers due to the slow and unpredictable release nature of organic fertilizers. Nutrients in organic fertilizers, particularly nitrogen (N), often fail to meet the demands of rapidly growing transplants in soilless substrate. This study aimed to develop fertilization guidelines for organic bell pepper (Capsicum annuum L.) transplants by evaluating the performance of one conventional fertilizer, two organic fertilizers (Drammatic, Pre-Empt), and one naturally derived fertilizer (Bio-Matrix) at a range of N rates in supporting transplant growth. Bell pepper transplants were grown in an indoor growing chamber for 28 days with weekly fertilizer application. We found that the initial nitrate-N concentration in the fertilizer solution was the sole predictor of shoot dry weight (R² = 0.62), confirming that N availability was the primary limiting factor for transplant growth. The conventional fertilizer produced the largest transplants (370.9 mg/plant in shoot dry weight) while Drammatic resulted in the lowest maximum shoot growth (196.6 mg/plant), likely due to its high salinity and the accumulation of ammonium in the substrate. Bell pepper transplants exhibited low nutrient uptake capability and resulted in low N recovery efficiency, especially with the two organic fertilizers, Drammatic and Pre-Empt (15.6% and 23.8%, respectively). Furthermore, we found no carryover effects of the fertilizer treatments during the transplant stage on bell pepper growth after being transplanted to the greenhouse for 18 days. The final shoot dry weight only correlated with transplant shoot dry weight at the time of transplanting (R² = 0.87) but not with fertilizer type (p = 0.2849). Overall, Pre-Empt emerged as the most effective fertilizer for organic bell pepper transplant production. It is cost-effective, has low electrical conductivity, and is associated with low ammonium accumulation in the substrate. Therefore, it can be applied at high N rates to meet the N demand of bell pepper transplants. Based on our growing conditions, we recommend 23.1 g/L substrate of Pre-Empt for organic bell pepper transplant production. Full article

Agriculture is facing increasing challenges due to labor shortages, rising productivity demands, and the need to operate in unstructured environments. Robotics, particularly soft robotics, offers promising solutions for automating delicate tasks such as fruit harvesting. While numerous soft grippers have been proposed, most focus on grasping and lack the capability to detach fruits with rigid peduncles, which require cutting. This paper presents a novel modular hexagonal soft gripper that integrates soft pneumatic actuators, embedded mechano-optical force sensors for real-time contact monitoring, and a self-centering iris-type cutting mechanism. The entire system is 3D-printed, enabling low-cost fabrication and rapid customization. Experimental validation demonstrates successful harvesting of bell peppers and identifies cutting limitations in tougher crops such as aubergine, primarily due to material constraints in the actuation system. This dual-capability design contributes to the development of multifunctional robotic harvesters capable of adapting to a wide range of fruit types with minimal requirements for perception and mechanical reconfiguration. Full article

Bacterial leaf spot, particularly in chili peppers, is major concern worldwide, particularly in chili peppers. Enhancing pepper resistance to bacterial leaf spot addresses a key agricultural challenge while minimizing chemical usage. In this study, the efficacy of plant resistance inducers (PRIs) in controlling bacterial leaf spot in peppers was evaluated through molecular and secondary metabolite analyses. Pepper plant seedlings were treated with salicylic acid (SA), acibenzolar-S-methyl, β-aminobutyric acid, chitosan, Bacillus subtilis B01, and B. velezensis CH6 and inoculated with Xanthomonas euvesicatoria pv. euvesicatoria. Disease severity was assessed, and the expression level of genes (PR-1, PR-2, PR-4, and CAT) and the abundance of secondary metabolites were analyzed via quantitative PCR (qPCR) and gas chromatography-mass spectrometry (GC-MS), respectively. Soil drenching with B. subtilis B01 produced the best effects, reducing the disease severity by 80% and significantly inducing PR-1 expression 24–48 h post-treatment. SA was similarly effective in inducing systemic acquired resistance (SAR), while β-aminobutyric acid primed antioxidative defenses through sustained catalase (CAT) expression, and chitosan induced PR-4. GC-MS analysis revealed secondary metabolites associated with systemic resistance pathways including SAR and induced systemic resistance (ISR). Herein, B. subtilis B01 and SA were identified as potent resistance inducers that reduce the disease severity of bacterial leaf spot and activate key defense pathways in pepper plants. These findings contribute to the development of sustainable, integrated disease management strategies. Full article