Celery (Apium graveolens var. dulce) is affected by several plant diseases, such as Fusarium oxysporum f. sp. apii (Foa). Four Foa races have been found in the US. The goals of this study were to determine which races are present in Costa Rica and to quantify the tolerance of the imported commercial cultivars of celery produced in the country. Isolates from 125 symptomatic celery plants from three different geographical locations were analyzed, 65 of which were selected for phylogenetic analysis. All isolates presented a short sequence of five nucleotides that differentiates Foa race 3 in the IGS rDNA region. Three different haplotypes closely related to race 3 were found, which were highly virulent, produced great losses, and affected all cultivars (resistant to races 2 and 4) of imported commercial celery. Additionally, five different cultivars of celery were evaluated against seven pathogen isolates identified as race 3 in greenhouse conditions. Two of the cultivars showed significantly less chlorosis, wilting, mortality, and higher fresh weight. Most of the Foa isolates significantly increased chlorosis, wilting, and mortality compared to non-inoculated control. Celery producers in Costa Rica lack access to seeds resistant to the Foa race 3 present in the country.

Tomato is one of the most important vegetable crops in Costa Rica, where favorable environmental conditions enabled year-round production but also promote bacterial diseases. In recent years, pith necrosis has been frequently observed; nevertheless, the causal agents remain unidentified in the country. This study evaluated bacteria associated with symptomatic plants collected in the Central Valley of Costa Rica. From 32 plants, 61 bacterial isolates were obtained, described morphologically, and characterized through basic biochemical tests. Partial sequencing of the 16S rRNA gene revealed diverse bacterial taxa, predominantly belonging to the genus Pseudomonas. Thirteen isolates were selected for pathogenicity assays, which confirmed variable virulence levels. Multilocus sequence analysis based on concatenated sequences of the 16S rRNA, gyrB, rpoD, and rpoB genes identified Pseudomonas alliivorans LTM 13.1.2, P. flavescens LTM 14.2.2, and P. capsici LTM 78.3.2 as causal agents of pith necrosis. Additionally, P. straminea LTM 78.2.1 and Cedecea sp. LTM 72.2.1 caused tissue discoloration. Whole-genome sequencing of the two most virulent isolates (LTM 13.1.2 and LTM 78.3.2) supported their taxonomic classification and revealed virulence-associated genes and biosynthetic clusters. This study represents the first report of these Pseudomonas species as tomato pathogens in Costa Rica and expands their known distribution and host ranges.

Tomato is one of the most widely cultivated and consumed vegetables in Costa Rica, where favorable environmental conditions enabled year-round production. However, these same conditions also promote the development of plant diseases. Diverse bacterial infections causing pith necrosis in tomato crops have become of frequent observation in recent years. Nevertheless, the causal agents in Costa Rica remain unidentified, and management strategies are poorly documented. This study evaluated the pathogenicity of bacterial isolates obtained from tomato plants collected in Costa Rica’s Central Valley. Isolates of Pseudomonas alliivorans, P. flavescens, and P. capsici were identified as causal agents of pith necrosis in tomatoes. Additionally, P. straminea and Cedecea sp. were associated with tissue discoloration. These findings provide valuable information to the tomato production sector in Costa Rica by identifying previously unreported pathogenic bacteria and expanding their known distribution and host ranges. These findings also demonstrate the ability of these isolates to cause pith necrosis.

We present the draft genome sequences of Pseudomonas alliivorans LTM 13.1.2 (6.1 Mb) and Pseudomonas capsici LTM 78.3.2 (5.8 Mb) isolated from tomato plants in Costa Rica. These draft genomes provide important insights into the virulence factors and antibiotic resistance genes of these plant pathogens.

The phytophagous mite Paraponychus corderoi (Baker & Pritchard 1962) (Acari: Tetranychidae) is native to some countries of the Latin American region. This species prompted the implementation of quarantine restrictions because it finds refuge in the natural crevices of the chayote (Sechium edule (Jacq.) Sw.) fruit. The farms located in the Ujarrás Valley of Costa Rica have ideal growing conditions for the chayotes and the mites. Due to morphological differences, it has been suggested that P.corderoi may in fact represent a cryptic species; however, the genetic diversity of these mites is not known. Mites from several farms were collected and mounted for further morphological and genetic analyses. A phylogeny was constructed, and the polymorphic sites and genetic diversity among populations were calculated using a haplotype network analysis. Females with long setae were frequently found around the farms followed by the variant with short setae. The phylogenetic tree revealed the relationship between Paraponychus and other genera within the Tetranychidae family. Genetic diversity among the populations revealed 13 different haplotypes. Morphological variants on the dorsal setae lengths showed no genetic differentiation, indicating intraspecific variation. The most genetically distant haplotypes, separated by 23 mutational steps, were found in the region of Santiago. These findings reveal substantial diversity within P. corderoi populations in a specific region of Costa Rica. Further comparative studies across the mite's range are needed to clarify species boundaries and diversity in this genus.