The antagonistic activities of five biocontrol agents: Trichoderma harzianum, Gliocladium roseum, Bacillus subtilis, Streptomyces noursei and Streptomyces natalensis, were tested in vitro against Colletotrichum acutatum and Colletotrichum gloeosporioides, the causal agents of anthracnose disease in fruit crops. The microbial antagonists inhibited mycelial growth in the dual culture assay and conidial germination of Colletotrichum isolates. The two Streptomyces species exhibited the strongest antagonism against isolates of C. acutatum and C. gloeosporioides. Microscopic examination showed that the most common mode of action was antibiosis. The results of this study identify T. harzianum, G. roseum, B. subtilis, S. natalensis and S. noursei as promising biological control agents for further testing against anthracnose disease in fruits. .

Aim Assessment of biological control of P. syringae pv. aptata using crude lipopeptide extracts (CLEs) of two Bacillus amyloliquefaciens strains (SS‐12.6 and SS‐38.4) and one Bacillus pumilus strain (SS‐10.7). Methods and Results The minimum inhibitory concentration (MIC) of CLEs and their combinations against the pathogen and potential interaction between the extracts were determined in vitro. The most effective antibacterial activity was achieved with the CLE from B. amyloliquefaciens SS‐12.6, with an MIC value of 0.63 mg ml⁻¹. Interactions between CLE combinations were mostly indifferent. The biocontrol potential of CLEs, mixtures of CLEs, and cell culture of B. amyloliquefaciens SS‐12.6 was tested on sugar beet plants inoculated with P. syringae pv. aptata P53. The best result in inhibiting the appearance of tissue necrosis (up to 92%) was achieved with B. amyloliquefaciens SS‐12.6 cell culture. Conclusion This work demonstrated significant biocontrol potential of the CLE and cell culture of B. amyloliquefaciens SS‐12.6 which successfully suppress leaf spot disease severity on sugar beet plants. Significance and Impact of the Study The findings of biocontrol of sugar beet emerging pathogen will contribute to growers in terms of alternative disease control management. This study represent first assessment of biological control of P. syringae pv. aptata.

Xylella fastidiosa is xylem-limited bacterium capable of infecting a wide range of host plants, resulting in Pierce's disease in grapevine, citrus variegated chlorosis, olive quick decline syndrome, peach phony disease, plum leaf scald, alfalfa dwarf, margin necrosis and leaf scorch affecting oleander, coffee, almond, pecan, mulberry, red maple, oak, and other types of cultivated and ornamental plants and forest trees. In the European Union, X. fastidiosa is listed as a quarantine organism. Since its first outbreak in the Apulia region of southern Italy in 2013 where it caused devastating disease on Olea europaea (called olive leaf scorch and quick decline), X. fastidiosa continued to spread and successfully established in some European countries (Corsica and PACA in France, Balearic Islands, Madrid and Comunitat Valenciana in Spain, and Porto in Portugal). The most recent data for Europe indicates that X. fastidiosa is present on 174 hosts, 25 of which were newly identified in 2021 (with further five hosts discovered in other parts of the world in the same year). From the six reported subspecies of X. fastidiosa worldwide, four have been recorded in European countries (fastidiosa, multiplex, pauca, and sandyi). Currently confirmed X. fastidiosa vector species are Philaenus spumarius, Neophilaenus campestris, and Philaenus italosignus, whereby only P. spumarius (which has been identified as the key vector in Apulia, Italy) is also present in Americas. X. fastidiosa control is currently based on pathogen-free propagation plant material, eradication, territory demarcation, and vector control, as well as use of resistant plant cultivars and bactericidal treatments.

Species of the genus Colletotrichum are among the most important plant pathogens globally, as they are capable of infecting many hosts—apple (Malus spp.) and other fruit and woody plant species—but also vegetable crops, cereals, legumes, and other annual and perennial herbaceous plants. The apple (Malus spp.) is attacked by various species from the genus Colletotrichum, whereby 27 different species from this genus have been described as the causative agents of apple bitter rot (ABR) and 15 as the cause of Glomerella leaf spot (GLS). These species generally belong to one of three species complexes: Colletotrichum acutatum, Colletotrichum gloeosporioides, and Colletotrichum boninense. The largest number of apple pathogens of the genus Colletotrichum belong to the species complex C. acutatum and C. gloeosporioides. However, further data on these species and the interactions between the species complexes of the genus Colletotrichum that cause these two apple diseases is needed for the development of effective control measures, thus ensuring successful and profitable apple cultivation. To contribute to this endeavor, a comprehensive review of the causative agents of ABR and GLS from the genus Colletotrichum is provided. In addition to presenting the species’ current names, distribution, economic significance, and the symptoms they cause in apple, their development cycle, epidemiology, and molecular detection strategies are described, with a particular emphasis on control measures.

Pseudomonas syringae pv. aptata is the causal agent of bacterial leaf spot disease of sugar beet ( Beta vulgaris ). During 2013, 250 samples were collected from leaf lesions with typical symptoms of bacterial leaf spot in commercial fields of sugar beet in Serbia, and 104 isolates of P . syringae pv. aptata were obtained. Identification and characterization was performed using biochemical, molecular and pathogenicity tests. Identification included LOPAT tests and positive reactions using primers Papt2F and Papt1R specific for P . syringae pv. aptata . Repetitive (rep) sequence‐based PCR typing with ERIC , REP and BOX primers revealed high genetic variability among isolates and distinguished 25 groups of different fingerprinting profiles. Pulse‐field gel electrophoresis ( PFGE ) and multilocus sequence analysis ( MLSA ) of representative isolates showed higher genetic variability than in rep‐ PCR analysis and distinguished three and four major genetic clusters, respectively. A pathogenicity test performed with 25 representative isolates on four cultivars of sugar beet confirmed the occurrence of leaf spot disease and showed correlation between the most aggressive isolates and the genetic clusters obtained in MLSA . All these findings point to the existence of several lines of P . syringae pv . aptata infection in Serbia that are genetically and pathologically different.