This research aimed to determine abilities of endophytic Aspergillus, Penicillium, and Trichoderma species to colonize grapevine cuttings, and to evaluate their performance for protecting pruning wounds from Botryosphaeriaceae fungi under greenhouse and field conditions. Colonization ability of five endophytic species (Aspergillus allahabadi, A. flavipes, Penicillium canescens, P. fructuariae-cellae, and Trichoderma brevicompactum) was assessed after introductions into cuttings using two inoculation methods: immersion in conidial suspensions or contact with dry conidia. Colonization by the inoculated fungi was subsequently confirmed through re-isolations, and species identities were verified by PCR and gene sequencing. After confirming colonization, biological activity of the endophytes was assessed against pathogens. Conidium suspensions were either sprayed onto host wounds or applied systemically to cuttings, and necrotic lengths in internal tissues were measured 4 months after inoculations. In a subsequent field experiment, conidium suspensions were applied by spraying onto pruning wounds, or placing mycelium/agar plugs, and extent of necroses was assessed 6 months after inoculations. Penicillium and Trichoderma species colonized internal tissues of grapevine plants, whereas Aspergillus species were not re-isolated. In greenhouse trials, the endophytes reduced lesion lengths caused by Botryosphaeriaceae species by 22 to 85 %. Under field conditions, and where applied to pruning wounds, these fungi gave 51 to 70% protection against Lasiodiplodia brasiliensis and Neofusicoccum parvum, with Trichoderma brevicompactum giving greatest efficacy. This study has shown that vineyard-derived Penicillium and Trichoderma endophytes can establish within grapevine tissues, and have potential to effectively suppress Botryosphaeriaceae pathogens of grapevines.
Citrus gummosis (citrus foot rot), commonly associated with Phytophthora spp. in citrus orchards, significantly limits citrus production in semi-arid regions, causing trunk cankers, gum exudation, and substantial yield losses. Field efficacy of an integrated disease management (IDM) programme combining chemical, cultural, and nutritional strategies was evaluated for reducing disease incidence and enhancing tree vigour and fruit yield. Over two years, trials were carried out across 12 commercial orchards. Cultural measures included soil aeration by collar excavation, conversion to dual-line drip irrigation, and application of well-decomposed organic manure as a surface mulch within the drip line. Assessments included disease incidence, severity of gum exudation, host plant vegetative growth, and fruit yields. Six months after implementation, disease incidence decreased from 65% at baseline to 20 ± 3% in the surviving IDM-treated trees, compared with 65 ± 5% in the untreated controls (GLMM treatment effect: χ²(1) = 48.3, P < 0.001). IDM-treated trees exhibited a 40% increase in shoot length and a 38% increase in trunk-diameter increment, while mean fruit yield increased from 15 ± 2 to 25 ± 3 kg tree⁻¹, corresponding to a 66.7% increase (P < 0.001). The IDM programme also improved tree recovery relative to the untreated controls in the semi-arid orchards evaluated. Although this IDM package gave short-term efficacy under the semi-arid conditions evaluated, its regional transferability should be validated through multi-location trials before broad implementation. Because Phytophthora pathogens were not isolated and identified, these results came from management of a macroscopic gummosis symptom complex, so long-term economic analyses and robust epidemiological monitoring are required to substantiate robust field recommendations.
In the summer of 2024, table grape plants (Vitis vinifera, “Sweet Celebration”) in Cieza (Murcia province, southeastern Spain) exhibited wood cankers and dieback symptoms consistent with Aspergillus vine canker (AVC). This study aimed to determine the aetiology of the disease and characterize the associated pathogens. Multi-locus phylogenetic analyses using cal and tub loci, combined with morphological characterization, identified Aspergillus niger and A. tubingensis from symptomatic plants. Mycelium growth patterns in response to temperature were similar for both species, with optimal growth between 30 and 33 °C, and no growth above 40 °C. Temperature also strongly influenced conidium germination. No germination occurred at 10 °C, and rapid and full germination occurred between 30 and 40 °C. Pathogenicity tests on table grape ‘Alphonse Lavallée’ showed that both species were pathogenic to grapevine wood, with A. niger exhibiting greater virulence. Inoculations on green leaves showed that both species colonized foliar tissues. These results confirm the association of A. niger and A. tubingensis with table grape cankers in southeastern Spain, and also highlight the ability of these fungi to develop at high temperatures, and pose potential threats to grape and wine production under warm Mediterranean conditions.
Fusarium crown and root rot is one of the main threats to asparagus production worldwide. The aetiology of the disease, attributed to several species of Fusarium and Neocosmospora, has not been re-evaluated in the context of recent advances in Fusarium taxonomy, and relevant studies in The Netherlands are scarce and outdated. Asparagus officinalis plants and associated soil samples were assessed from 38 cultivated fields and one location where this plant naturally occurs in The Netherlands. A total of 164 specimens were obtained yielding 551 fungal strains. Fungal identification according to DNA sequencing and phylogenetic analyses based on fragments of the translation elongation factor 1-alpha (tef1) and the DNA-directed RNA polymerase II second largest subunit (rpb2) showed that these isolates belonged to 20 taxa (Fusarium acuminatum, F. annulatum, F. avenaceum, F. carminascens, F. celtidicola, F. clavus, F. cugenangense, F. culmorum, F. equiseti, F. flagelliforme, F. flocciferum, F. inflexum, F. nirenbergiae, F. odoratissimum, F. oxysporum, F. redolens, F. vanleeuwenii, Neocosmospora geoasparagicola, N. solani and N. stercicola), of which 11 species (Fusarium avenaceum, F. carminascens, F. celtidicola, F. clavus, F. cugenangense, F. flagelliforme, F. flocciferum, F. inflexum, F. odoratissimum, F. vanleeuwenii and N. stercicola) are first reports on A. officinalis. These results, and testing of Koch’s postulates on A. officinallis plantlets, showed that F. annulatum, F. culmorum, F. redolens, F. nirenbergiae and N. solani were the most prevalent and aggressive species. In contrast, although F. oxysporum is pathogenic to A. officinalis, it was among the least prevalent species encountered in this study.
Ornamental plants can be reservoirs of plant viruses, facilitating virus dissemination through international trade. In this bougainvillea study, 58 samples collected from six ornamental nurseries in Apulia (southern Italy) were screened for the presence of known bougainvillea-infecting viruses, using PCR assays. Among the viruses tested, only Bougainvillea chlorotic vein banding virus (BCVBV) was detected, occurring in five (8.6%) of the samples, whereas Impatiens necrotic spot virus (INSV), Clerodendron yellow mosaic virus (ClYMV), tomato yellow ring virus (TYRV), and cucumber mosaic virus (CMV) were not detected. High-throughput sequencing (HTS) of one BCVBV-positive sample (O54) enabled reconstruction of a complete viral genome, designated BCVBV Mini-Thai (GenBank accession no. PQ682517). A second HTS analysis of a pooled set of PCR-negative samples revealed a genetically distinct BCVBV isolate that was not detected by PCR using previously published primers. The complete genome of this isolate was reconstructed through contig assembly and gap-filling PCR using newly designed primers, and was named BCVBV Apulia 1 (PQ682518). The genome of Mini-Thai was 8,822 nucleotides long, and had high nucleotide (98.5%) and amino acid (98.7%) similarities with the Malaysian isolate BCVBV-UKM. In contrast, BCVBV Apulia 1 (PQ682518) was 8,694 nucleotides long and had greatest nucleotide similarity (81.6%) with the Brazilian isolate BCVBV UNB-01, with 84.0% amino acid similarity in the polyprotein. Both isolates had typical Badnavirus genome organization, with four open reading frames, and clustered in distinct phylogenetic clades. Further screening of the 58 collected samples using primers designed on the Apulia 1 isolate detected seven (12.1%) additional infected samples. A primer set targeting conserved genomic regions was also developed, enabling detection of both isolates. This report is the first detection of BCVBV in Italy and Europe, and also reveals the presence of a genetically divergent isolate of this virus.
