Tomatoes (Solanum lycopersicum L.) are the most cultivated and important vegetable crop in the world. These plants can wilt during crop growth due to fusarium wilt (fusariosis), a disease that damages tomato vascular systems. The Fusarium isolated and analyzed in this work correspond to Fusarium oxysporum f. sp. radicis-lycopersici. The isolates were molecularly identified, and analysis was done on the in vitro effects of the nanoemulsions (previously obtained from extracts of Chilean medicinal plants of the genera Psoralea and Escallonia) to inhibit mycelial and conidial germination of the isolates. Subsequently, the nanoemulsions were evaluated under greenhouse conditions for preventive control of fusariosis in the root and crown, with high levels of disease control observed using the highest concentrations of these nanoemulsions, at 250 and 500 ppm.

Botryosphaeria dieback (BD) occurs in young and old plants. In the field, the prevalence and severity of the disease increase proportionally with the age of vineyards. Among the pathogens that cause BD, Diplodia seriata is the most prevalent species in Chile and other countries with a Mediterranean climate. To date, no information is available on the susceptibility of adult wood to infection by this pathogen since most of the pathogenicity tests have been carried out on 1- or 2-year-old shoots or detached canes. Therefore, a pathogenicity test was carried out on plants under field conditions, with inoculations in 1-year-old shoots and 2- and 10-year-old wood in grapevine cv. Cabernet Sauvignon. A pathogenicity test was carried out with two isolates of D. seriata. The results for the plants show that D. seriata was significantly more aggressive on the 10-year-old than on the one- or two-year-old tissue, where the lesions were 4.3 and 2.3 cm on average, respectively. These results were compared with the lesions obtained from two-year-old canes after the isolates were activated in grape berries. Also, the Chilean isolates of D. seriata were compared phylogenetically with those from other countries, and no major differences were found between them. Our results are consistent with the damage observed in the field, contributing to the knowledge of the epidemiology of this disease in Mediterranean climates. In the future, the effect observed in cv. Cabernet Sauvignon with D. seriata on virulence at different tissue ages should be tested for other BD-causing agents and wine varieties.

Phylogenetic analyses categorize seven genotypes of citrus tristeza virus (CTV). The symptoms caused by this pathogen, their expression and severity are influenced by CTV genotypes, host species, cultivars, and infected host rootstocks. This study aimed to verify how populations of Chilean CTV isolates changed following inoculation from infected sweet orange to Mexican lime trees, and to determine if CTV genotype populations influenced transmission efficiency via Aphis gossypii. Reverse transcription polymerase chain reaction showed variation in genotypes of populations of CTV in Mexican lime, after graft inoculations using infected sweet orange chip-buds. Severe genotypes (VT) were detected after inoculation of mild isolate CTV populations (T30). The T30 donor populations also reduced transmissibility via A. gossypii; however, these results may not be conclusive due to mixture with the VT genotype. There is evidence of high rates of virus acquisition by this aphid species, but also low transmission efficiency, which may partially explain the historical absence of tristeza epidemics in Chile.

Avocado, a fruit consumed worldwide and essential for countries like Mexico and Chile, faces significant postharvest challenges, particularly during prolonged storage and transportation periods, where Botryosphaeriaceae and Glomerellaceae genera cause fruit rots that can generate substantial economic losses. This study investigated three Hass avocado orchards in the Valparaíso region of Chile to identify spore dispersion peaks, analyze the aerial dynamics of fungal inoculum, and evaluate the association with climatic conditions, as well as the incidence (I) and damage index (DI) of fruit rots. Spore traps were installed in symptomatic trees and monitored weekly over 13 months. Meteorological data were collected in parallel. Fruits from these orchards were sampled to evaluate postharvest rots, physiological maturity, and disease severity using molecular techniques, including DNA sequencing and phylogenetic analysis of isolated pathogens. The results revealed that spore peaks for both fungal families were closely associated with increased rainfall and high relative humidity, particularly from June to mid-September (winter season). The Santo Domingo orchard exhibited the highest disease pressure, with stem-end rot reaching an I of 44% and a DI of 17.25%, and anthracnose reaching an I of 23% and a DI of 12.25%. This study provides the first long-term, field-based evidence of airborne spore dynamics of Botryosphaeriaceae and Glomerellaceae in Chilean avocado orchards and their statistical relationship with environmental variables. These findings highlight the potential of incorporating climatic indicators—such as rainfall thresholds and humidity levels—into monitoring and early-warning systems to optimize fungicide application timing, reduce unnecessary chemical use, and improve postharvest disease management in avocado production.

In vineyards, Botryosphaeria dieback (BD) occurs in young and old plants. In the field, the prevalence and severity of the disease increase proportionally with the age of the vineyards. Among the pathogens that cause (BD), Diplodia seriata is the most prevalent species in Chile and other countries with a Mediterranean climate. To date, no information is available on the sus-ceptibility of adult wood to infection by this pathogen since most of the pathogenicity tests have been carried out on 1- or 2-year-old shoots or detached canes. Therefore, a pathogenicity test was carried out on plants under field conditions, with inoculations in plants, on one-year-old shoots, and 2- and 10-year-old wood in grapevine cv. Cabernet Sauvignon. A pathogenicity test was carried out with two isolates of D. seriata selected in an assay in detached canes that were 2-year-old. The results on plants showed that D. seriata was significantly more aggressive on 10-year-old than on one- or two-year-old tissue. These results were compared with the lesions ob-tained from two-year-old canes. The results of this work are consistent with the damage ob-served in the field, highlight the importance of identifying each pathogenic species that causes (BD) and contribute to the knowledge of the epidemiology of this disease in Mediterranean cli-mates.

Background: Since 2008, the kiwifruit industry has been significantly impacted by Pseudomonas syringae pv. actinidiae (Psa), the agent responsible for bacterial canker in kiwifruit. Existing treatments, such as copper-based compounds and antibiotics, have faced challenges related to resistance and soil contamination. Phage therapy is a promising and safe alternative for controlling this pathogen. This study aimed to evaluate the use of a mixture of four isolated and characterized bacteriophages as potential biocontrol agents against Psa. Methods: Trials were conducted at two locations in Chile, where Psa presence was reported during the 2019/2020 and 2020/2021 seasons, with a focus on the spring stages. Different formulations were tested each season to evaluate possible improvements in effectiveness. Pseudomonas spp. isolates obtained from epiphyte populations were characterized using morphological, biochemical (LOPAT), and molecular techniques. Results: Field trials demonstrated that the phage mixture effectively reduced the damage associated with Psa on kiwi leaves, resulting in a decrease in the Pseudomonas spp. bacterial load (42.9% for Peumo and 25% for Linares) at both locations during the first season trials. This decrease is associated with a reduction in the incidence and severity of the disease in kiwi plants in the Peumo orchard. In both seasons, bacteriophages reduce Psa symptoms in treated kiwi plants compared to untreated controls, at least at one location and evaluation. In both orchards during the first season, bacteriophages also outperformed copper- and antibiotic-based treatments used by farmers. Bacteriophage therapy is eco-friendly and safe for both applicators and consumers.