Expansion of avocado production areas in Colombia has led to an increased demand for plant propagation material. However, this expansion has exacerbated phytosanitary challenges, particularly root rot disease mainly associated with Phytophthora spp. Therefore, this study aimed to identify Phytophthora species associated with root rot in avocado seedlings within nurseries. Avocado plants exhibiting wilting symptoms were collected from nurseries in the departments of Quindío, Risaralda, and Valle del Cauca (Colombia). Segments of diseased roots were selected, cut, and surface-disinfected, before being planted on Potato Dextrose Agar (PDA) supplemented with antibiotics and fungicides. Microorganism identification was conducted using taxonomic keys and confirmed by molecular techniques employing the identification based on phylogenetic hypothesis, using ITS1-5.8s-ITS2 region encoding for rRNA. Isolates obtained from necrotic avocado roots were identified as P. cinnamomi and P. heveae. The pathogenicity of the isolates was confirmed in avocado seedlings through inoculation, resulting in symptom reproduction. Consequently, this study identified P. cinnamomi and P. heveae as causal agents of root rot in avocado during the nursery stage.

El objetivo de la presente publicación es reunir y facilitar el acceso a conocimientos técnicos de la producción de lima ácida Tahití para pequeños y medianos productores del cultivo, los empresarios del sector, la comunidad académica del área frutícola de nivel profesional y técnico, y los asistentes técnicos agropecuarios del cultivo en Colombia. Por otra parte, también se pretende recopilar información para las instituciones relacionadas con el agronegocio de este cultivo en el país, con el fin de mejorar la competitividad, tanto para el mercado interno como para el de exportación. En la publicación se presentan los últimos resultados de la investigación acerca de la lima ácida Tahití en Colombia, datos detallados sobre las características ambientales de las principales regiones productoras, aspectos botánicos y de recursos genéticos, y sistemas de propagación. Así mismo, se exponen las recomendaciones más relevantes para el manejo del cultivo, incluyendo el aspecto productivo, el componente fitosanitario, las prácticas de manejo agronómico, las recomendaciones de cosecha y poscosecha, y los indicadores económicos y financieros.

Hass avocado fruit diseases are one of the main marketing constraints in Colombia. To identify and reveal the diversity of fungi associated with diseases in fruits and peduncles, symptomatic samples were collected from 67 farms in the 9 main Hass avocado-producing municipalities of the department of Cauca located in southwestern Colombia. A total of 237 monosporic isolates were obtained that were subjected to DNA extraction, amplification of the ITS region, sequencing and functional diversity analysis based on Hill numbers by municipality and altitude. The results indicated that the genera Pseudocercospora, Diaporthe, Colletotrichum, Neofusiococcum, Lasiodiplodia and Pestatoliopsis were associated with fruit diseases. The genus with the highest number of effective species was Colletotrichum. The ITS region revealed 100% identity of the species Pseudocercospora norchiensis, which was the first report of this pathogen in the crop. There was a greater richness and diversity of associated species in the three municipalities, revealing that the higher the altitude was, the lower the richness and diversity of fungi associated with fruit diseases. These results will provide a better understanding of the identification and diversity of pathogenic microorganisms present in avocado production systems in this region of Colombia.

La producción de material de siembra de cítricos en condiciones protegidas es una de las principales alternativas de prevención de la que se dispone para evitar la contaminación de las plantas y enfrentar la enfermedad por HLB, principal causa de muerte de los cítricos en el mundo. En Colombia, es de vital importancia que el sector viverista, que produce cítricos para las diferentes regiones citrícolas, pueda acoger las recomendaciones contenidas en la norma de certificación 12816 de 2019, del Instituto Colombiano Agropecuario (ICA). Para avanzar en la producción de semilla de cítricos con calidad genética, fisiológica y fitosanitaria, se elaboró este manual con información de más de diez años de investigación obtenida en condiciones protegidas de la Corporación Colombiana de Investigación Agropecuaria (AGROSAVIA), del Centro de Investigación Palmira, y que se constituye en el primer documento con información práctica, producto de la producción a escala semicomercial de plantas de cítricos. En este documento, se presentan las principales características de la producción de material de siembra de cítricos en condiciones protegidas de casa de malla para asegurar la sanidad y calidad del material. Este manual de consulta incluye diferentes aspectos relacionados con la producción de los cítricos, como el tipo de infraestructura recomendadas; la descripción de las condiciones ambientales adecuadas para el desarrollo de las plantas; la selección y acondicionamiento de semillas; las principales características y fuentes de sustratos para la producción de portainjertos; el desarrollo de copas comerciales como naranjas, mandarinas y limas ácidas, y su comportamiento sobre diferentes portainjertos; la descripción de las principales plagas, enfermedades y malezas más frecuentes en los ambientes protegidos y su manejo integrado. Este manual está dirigido a viveristas, ingenieros agrónomos, productores de cítricos, académicos, extensionistas, entre otros. Es ideal para personas que quieren avanzar en la producción de semilla de cítricos con calidad genética, fisiológica y fitosanitaria.

Citrus is the second most important fruit crop in Colombia after bananas, with production taking place in 26 of the country’s 32 departments. Oranges, sour limes, and mandarins are the most economically important crops in terms of area planted and production. Microsatellites were used to assess the genetic differentiation of oranges, mandarins, tangelos, grapefruits, and acid limes from the Colombian Agricultural Research Corporation AGROSAVIA germplasm bank and collection of micro-grafted plants at Palmira Research Center in Colombia. A total of 121 samples from eight citrus groups were analyzed with 30 fluoromarked simple sequence repeats (SSR) microsatellites. The mean expected heterozygosity and mean observed heterozygosity were 0.58 and 0.57, respectively, and the coefficient of genetic differentiation was 0.558, confirming very high genetic differentiation among the citrus groups evaluated. Microsatellites mCrCIR01B02, AMB5, Ci01C09, mCrCIR08B08, and Ci01C07 were the most informative, presenting a high number of alleles and polymorphic loci percentages of more than 45 %; in addition, they allowed the identification of unique alleles, which can be used to establish the genetic fingerprint of citrus. Genetic differentiation was achieved for seven out of the eight groups evaluated. The SSRs used failed to differentiate the orange groups, possibly due to genetic origin; for this group, other molecular markers are recommended.

Pineapple (Ananas comosus) crop generates a high volume of harvest residues, resulting in significant environmental impact, primarily due to the large quantity of biomass left after fruit harvesting. This study aimed to evaluate fiber production and quality using two defibration methods, manual and mechanical, on leaves from three strata of MD2 pineapple plants subjected to different pre-conditioning techniques: soaking in water for 8 and 15 days, and NaOH solution for 1 hour. Results of this study demonstrated that 70 % of the leaves were suitable for defibration. The highest fiber yields were obtained from leaves in the middle and upper strata of the plants, with values of 8.98 and 12.4 g, respectively. The extraction time was shorter in the mechanical method, being 22 times more efficient than the manual method. The mechanical method favored fiber production when no prior conditioning of the leaves was performed, extracting an average of 50.5 g per plant. The manual method performed better when leaves were subjected to soaking in water or NaOH, extracting between 14.5 and 16.3 g per plant. Additionally, changes in the mechanical properties of the fiber were found to depend on the stratum of the plants and leaf pre-conditioning techniques. Our results contribute to explore the potential uses of fiber extracted by strata and highlight the possibilities of implementing pre-conditioning techniques.