Background and aims Locally produced bio-inoculant consortium and plant bioactive extract were studied as sustainable management options to boost maize production. Methods The field study was conducted from 13th April to 15th July 2021 and repeated on another field site from 5th May to 4th August 2023 to avoid residual effects while validating reliability of the treatments. Experiments were set up as randomized complete block design with 5 treatments including a Control (No input), Chemical (NPK fertilizer + synthetic insecticide), Organic (Poultry manure + Piper guineense), and locally produced or commercial bio-inoculant of plant growth-promoting bacteria, with 4 replicates. Results Local inoculum significantly (P < 0.05) increased maize grain yield than untreated control. Microbial and organic amendments produced comparable maize grain yield to chemical input, which were significantly higher than the untreated control (P < 0.05). The local inoculum reduced fall armyworm (FAW) infestation of maize cobs by 18% and 31% in 2021 and 2023, respectively, compared to untreated control (P < 0.05). Stem borer infestation also reduced significantly (P < 0.05) across treatments for both years, with the lowest in local inoculum (6%), followed by commercial inoculum (31%), organic (52%), chemical (42%), and control (100%) in 2021, with a similar trend observed in 2023. In 2021, amounts of plant available phosphorus and exchangeable potassium were 71 mg kg(-1) and 1010 mg kg(-1) soil, respectively, in the locally produced bio-inoculant consortium, which were significantly (P < 0.05) higher than 30 mg kg(-1) and 374 mg kg(-1) in the control, respectively, and a similar trend was observed in 2023.

Root-knot nematodes (Meloidogyne spp.) are significant pests that cause considerable damage to crops, prompting a need for sustainable control methods. This study evaluated the nematicidal potential of fungal culture filtrates and botanicals as eco-friendly alternatives. In vitro tests demonstrated that Lemongrass oil (LG) (0.2%) achieved the highest mortality of nematode juveniles (J2s) at 99.44% within 48 h, while Pochonia chlamydosporia (Pc) (2%) and Purpuricillium lilacinum (Pl) (2%) reduced egg hatching rates to 9.57% and 11.43%, respectively. Neem oil (NM) (0.2%) was the most effective in preventing J2 root penetration (4.42%). In vivo, a combination treatment (T7) of NM (0.2%), Trichoderma harzianum (Tz) (2%), Pl (2%), and LG (0.2%) applied at 10 day intervals significantly reduced the nematode reproduction factor to 0.035, comparable to the chemical control Bayer Velum Prime (R) (Fluopyram 34.48% W/W SC) (0.031). T5 (NM and Tz) resulted in the highest shoot biomass (236.73 +/- 1.38 g), while Bayer Velum Prime (R) (Fluopyram 34.48% W/W SC) increased root biomass (31.75 +/- 1.24 g). Additionally, T7 produced the longest shoots (63.37 +/- 0.74 cm) and roots (36.80 +/- 0.3 cm), with fewer root galls (55.67 +/- 1.53) and egg masses (4 +/- 0.01). T7 also minimized the final soil nematode population to 106.33 +/- 1.01 per 100 g, closely followed by T8 (94.67 +/- 0.89). These results indicate that combining NM, Tz, Pl and LG provide effective nematode control without phytotoxic effects, enhancing plant growth and offering a promising sustainable alternative to chemical nematicides.

Root-knot nematode (RKN) (Meloidogyne incognita) is a major plant parasitic nematode that severely damages crops, leading to significant yield losses and substantial economic impact globally. This study aims to investigate an environmentally sustainable biological strategy for mitigating parasitic populations of the root-knot nematode, M. incognita. Specifically, the research focuses on assessing the nematicidal efficacy of Acalypha indica against M. incognita mortality and second-stage juveniles' (J2) hatching under controlled in vitro conditions. A. indica leaf aqueous extract was applied at varying concentrations (250, 500, 750, and 1000 ppm) to J2s and egg masses of M. incognita. Notably, at 1000 ppm, a significant increase in J2 mortality and hatching inhibition was observed, while 250 ppm concentration showed the least favorable outcome; with mortality rates ranging from 22-82%. Chemical analysis via gas chromatography-mass spectroscopy (GC-MS) identified Benzoic acid, Cyclooctasiloxane, and 3-Isopropoxy-1,1,1,7,7,7-hexamethyl-3,5,5-tris (trimethylsiloxy) tetrasiloxane as predominant compounds. The nematicidal activity of A. indica leaf extract was further validated through in silico molecular docking, revealing that benzoic acid, Cyclooctasiloxane, and 3-Isopropoxy-1,1,1,7,7,7-hexamethyl-3,5,5-tris (trimethylsiloxy) tetrasiloxane bind to the ODR 3 protein of M. incognita with binding energies of -15.72, -8.91, and -7.35 kJ/mol, respectively. These findings hold promise for environmentally benign root-knot nematode management, contributing to improved soil health.

The root-knot nematode, Meloidogyne incognita, poses a significant economic threat as an endoparasite for various vegetables, including cabbage. Utilizing botanicals is an essential aspect of green technology to combat root-knot nematode infection. This study investigates the efficacy of four botanicals (Oxalis corniculata, Ricinus communis, Lantana camara, and Pluchea lanceolata) as emerging phyto-nematicides against M. incognita using both in vitro experiments (J2 mortality after 24, 36 and 48 hours exposure to 3000, 2000, 1000, 500, and 0 mg/L of the four botanicals and then determination egg hatching of M. incognita after 3 and 5 days incubation with various concentrations of the selected botanicals) and pot experiments. In the in vitro study, different extracts from the leaves of botanicals were applied to the second juvenile stage (J2) of M. incognita. The highest mortality of J2 and reduction in egg hatching for O. corniculata extract (89.96 and 86.79%), while the lowest effects (9.01 and 11.50 %) were observed for P. lanceolata extract. The extract of O. corniculata caused complete damage to the morphology of J2 via rupturing the cuticle of posterior, middle, and interior portion. In the pot experiment, M. incognita adversely affected growth shoot length (51.37%), root length (55.10%), fresh head weight (63.14%), and dry head weight (61.79%) by down-regulation of biochemical and epidermal traits compared to un-inoculated plants. However, the soils amended with botanicals especially O. corniculata recorded highest retardation of M. incognita infestation in cabbage roots, hence improved the growth and yield compared to the infected plants. The most beneficial effect denoted by O. corniculata at 100 g/pot on the infected cabbage plants associated with improving carotenoids (83%), chorophyll (117%), and nitrate reductase activity (79%) compared to stressed plants only. Also, O. corniculata at 100 g/pot maximally increased the number of stomata (130%), lengths (87%), and width (141%) of stomatal pore infected cabbage plants compared to the infected plants. These findings recommended the importance of O. corniculata as an eco-friendly organic phyto-nematicide that effectively restrict the damaging impacts of M. incognita on cabbage and may be other crops.

Plant-parasitic nematodes pose a significant threat to finger millet crops, potentially causing yield reduction of up to 70%. Extracts derived from finger millet varieties contain potent bioactive compounds that can mitigate nematode damage and promote plant growth. This study aimed at isolating and characterizing bioactive compounds from the finger millet varieties Ikhulule, Okhale-1, and U-15; evaluating the impact of Ikhulule and U-15 extracts on the mortality of the root lesion nematode Pratylenchus vandenbergae; assessing the growth promotion effects of Ikhulule and U-15 extracts on the finger millet variety Okhale-1; and determining the efficacy of these extracts in managing plant-parasitic nematodes under greenhouse conditions. Extracts were obtained from both leaves and roots and tested in vitro for nematode mortality and in vivo for growth promotion and nematode control. The results showed that finger millet extracts exhibited strong nematicidal properties in vitro, achieving a mortality rate of up to 98% against P. vandenbergae nematodes. Applying these extracts to finger millet shoots significantly reduced nematode populations in both soil and roots and decreased the reproductive factor to below one (1), indicating an effective nematode control. The study attributes the enhanced nematicidal effects of finger millet extracts to their bioactive compounds, particularly dodecanoic acid, phytol, 1,1,4a-trimethyl-6-decahydro naphthalene, 2,3-dihydro-benzofuran, 2-methoxy-4-vinylphenol and ethyl ester, and hexadecanoic acid. These findings suggest that finger millet-derived extracts offer a natural solution for nematode management and broader agronomic benefits, ultimately contributing to overall plant health and productivity.

Common bean production is constrained by a multitude of biotic constraints including bean flies and Fusarium wilt in tropical and subtropical farming systems globally. As these pests and diseases attack the crop beneath the soil, excessive applications of synthetic pesticides are frequently used for their control. The use of plant-based pesticides could be a more sustainable management approach; however, few studies have investigated their application for controlling soil-borne pests and diseases. This study aimed to evaluate the efficacy of pesticidal plants and soil fertility management for controlling bean fly (Ophiomyia spp.) and Fusarium wilt (Fusarium spp.) using extracts and pastes of Azadirachta indica, Tephrosia vogelii, Tagetes minuta, Lippia javanica, Cymbopogon citratus and Ocimum gratissimum. To protect against Fusarium wilt and bean fly, pesticidal plants were applied as a seed coating and/or foliar spray, and demonstrated that common bean seeds coated with T. vogelii resulted in higher yields than other pesticidal plants and the synthetic pesticide control treatment. Treatments to target bean fly damage showed no significant difference between application methods on the oviposition rate of bean fly. An integrated treatment of T. minuta with 2 g Diammonium phosphate fertilizer and high compost led to higher yields than other treatments. Our results indicate that key soil-borne pests and pathogens of common bean can be effectively managed without synthetic pesticide inputs, while seed ball pastes of pesticidal plants combined with soil fertility management can increase crop yields using cost-beneficial agroecological farming systems.

Fusarium head blight (FHB), caused by Fusarium graminearum, is a predominant disease of wheat. Due to the lack of disease-resistant germplasm, chemical control is an important means to control wheat scab. Volatile substances produced in near-isogenic wheat lines were detected after inoculation with F. graminearum, and 4-propylphenol, which appears in FHB-resistant lines, was identified. In vitro and in vivo antifungal activity tests demonstrate that 4-propylphenol effectively inhibits the mycelial growth of F. graminearum. Metabolomics analysis showed changes in glutathione metabolism, indicating that 4-propylphenol triggered reactive oxygen species (ROS) stress. This was consistent with the increasing ROS levels in Fusarium cells treated with 4-propylphenol. Further results demonstrated that excessive accumulation of ROS induced DNA and cell membrane damage in the mycelium. Moreover, 4-propylphenol showed different degrees of inhibition against other soil-borne pathogens (fungi and oomycetes). These findings illustrated that 4-propylphenol has broad spectrum and high antifungal activity and should be considered for use as an ecological fungicide.