Genera Pseudomonas and Xanthomonas include bacterial species that are etiological agents of several diseases of major vegetable crops, such as tomato, pepper, bean, cabbage and cauliflower. The bacterial pathogens of those genera may cause severe crop damage, leading to symptoms like leaf spots, wilting, blights, and rotting. These plant pathogens can affect propagation materials and spread rapidly through plant tissues, contaminated soils, or water sources, making them challenging to control using conventional chemical products alone. Biopesticides, such as essential oils (EOs), are nowadays studied, tested and formulated by employing nano- and micro-technologies as innovative biological control strategies to obtain more sustainable products using less heavy metal ions. Moreover, there is a growing interest in exploring new biological control agents (BCAs), such as antagonistic bacterial and fungal species or bacteriophages and understanding their ecology and biological mechanisms to control bacterial phytopathogens. These include direct competition for nutrients, production of antimicrobial compounds, quorum quenching and indirect induction of systemic resistance. Optimisation of the biocontrol potential goes through the development of nanoparticle-based formulations and new methods for field application, from foliar sprays to seed coatings and root inoculation, aimed to improve microbial stability, shelf life, controlled release and field performance. Overall, the use of biological control in horticultural crops is an area of research that continues to advance and shows promising potential. This review aims to provide an in-depth exploration of commercially accessible biocontrol solutions and innovative biocontrol strategies, with a specific focus on the management of bacterial diseases in vegetable crops caused by Pseudomonas and Xanthomonas species. In this article, we highlighted the advancements in the development and use of EOs and other BCAs, emphasizing their potential or shortcomings for sustainable disease management. Indeed, despite the reduced dependence on synthetic pesticides and enhanced crop productivity, variable regulatory frameworks, compatibility among different BCAs, and consistent performance under field conditions are among the current challenges to their commercialization and use. The review seeks to contribute valuable insights into the evolving landscape of biocontrol in vegetable crops and to provide guidance for more effective and eco-friendly solutions against plant bacterial diseases.

Forage cover crops have the potential to improve soil quality and orchard productivity, but their effects on wolfberry (Lycium barbarum L.) plants are still unclear. In this study, we conducted field and greenhouse experiments between 2019 and 2021, with 10 forage species as cover crops. We observed the growth, yield, fruit quality, and photosynthetic characteristics of wolfberry plants, as well as the occurrence of plant diseases and pests. Based on averaged data for all forage species, cover cropping facilitated plant growth, maintained fruit yield, and promoted leaf photosynthesis in wolfberry compared to monocropping. This was exemplified by a notable increase in the branch number of wolfberry plants under ryegrass treatment, with marginal increase in branch length under evergreen grass (lvyuan 5) and mangold treatments. Cover cropping additionally improved wolfberry quality through increasing carotenoid, flavonoid, and ascorbic acid contents by 21%, 53%, and 127%, respectively (P < 0.05). The presence of mangold, alfalfa, sweet sorghum, ryegrass, and feather grass reduced powdery mildew-induced leaf damage in wolfberry plants by 69% (P < 0.05). When alfalfa, feather grass, and ryegrass were used, the risk of aphid infestation was lowered by 67% (P < 0.05). Collectively, the results indicated that mangold, ryegrass, and alfalfa were the optimal cover crops for sustainable wolfberry production in the study area. The use of appropriate forage cover crops enhanced plant growth and fruit quality of wolfberry by stimulating photosynthetic capacity and biotic stress resistance.

Myxobacteria have a complex life cycle and unique social behavior, and obtain nutrients by preying on bacteria and fungi in soil. Chitinase, beta-1,3 glucanase and beta-1,6 glucanase produced by myxobacteria can degrade the glycosidic bond of cell wall of some plant pathogenic fungi, resulting in a perforated structure in the cell wall. In addition, isooctanol produced by myxobacteria can lead to the accumulation of intracellular reactive oxygen species in some pathogenic fungi and induce cell apoptosis. Myxobacteria can also perforate the cell wall of some plant pathogenic oomycetes by beta-1,3 glucanase, reduce the content of intracellular soluble protein and protective enzyme activity, affect the permeability of oomycete cell membrane, and aggravate the oxidative damage of pathogen cells. Small molecule compounds such as diisobutyl phthalate and myxovirescin produced by myxobacteria can inhibit the formation of biofilm and lipoprotein of bacteria, and cystobactamids can inhibit the activity of DNA gyrase, thus changing the permeability of bacterial cell membrane. Myxobacteria, as a new natural compound resource bank, can control plant pathogenic fungi, oomycetes and bacteria by producing carbohydrate active enzymes and small molecular compounds, so it has great potential in plant disease control.