Las bacterias Xenorhabdus y Photorhabdus están asociadas simbióticamente con nematodos de las familias Steinernematidae y Heterorhabditidae respectivamente. Se caracterizan por producir un complejo de sustancias como toxinas, antibióticos y enzimas extracelulares que matan los insectos. Con el objetivo de seleccionar los nematodos más patogénicos y su nivel de producción de antibióticos se propuso evaluar la patogenicidad de 13 aislamientos nativos. Las bacterias se aislaron de juveniles infectivos (JIS) por macerado directo, se cultivaron en medios microbiológicos selectivos (NBTA y MacConkey) y se describieron fenotípica y bioquímicamente. La patogenicidad se evaluó en larvas de último instar de G. mellonella L. (Lepidóptera: Pyralidae), mediante diluciones seriadas de inóculo bacteriano con una concentración de 10(4)cel/ml. Se registró el porcentaje de mortalidad a las 12, 24 y 48 horas y las unidades formadoras de colonia (UFC) en agar NBTA, en los mismos intervalos de tiempo. Los datos se sometieron a un análisis de varianza y a la prueba de comparación de medias de Duncan. Las pruebas bioquímicas y enzimáticas resultaron positivas para el género Xenorhabdus. Los análisis estadísticos mostraron que los aislamientos, UNPX04, UNPX15 provenientes de La Florida-Risaralda y Llano Bajo-Valle del Cauca respectivamente, causaron el 100 % de mortalidad a las 12 y 24 horas en contraste con siete aislamientos que causaron sólo el 70% de mortalidad.

Xenorhabdus and Photorhabdus bacteria are symbiotically associated with nematodes of the families Steinernematidae and Heterorhabditidae respectively. They are characterized by producing a complex of substances such as toxins, antibiotics and extracellular enzymes that kill insects. In order to select the most pathogenic nematodes and antibiotic production level, it was propose to evaluate the pathogenicity of 13 native isolates. Bacteria were isolated from infective juveniles (JIS) by direct macerated, cultured on selective media (NBTA and MacConkey) and described phenotypic and biochemically. The pathogenicity was evaluated on the last instar larvae of G. mellonella, using serial dilutions of the bacterial inoculum with a concentration of 104cel/ml. The mortality rate was registered at 12, 24 and 48 hours and the colony forming units (CFU) in NBTA agar in the same intervals of time. The data were analyzed by variance analysis and mean comparison by Duncan test. Biochemical and enzymatic tests were positive for the genus Xenorhabdus. The results showed that the isolates UNPX04, UNPX15 from agricultural soils of Florida -Risaralda and Llano Bajo- Valle del Cauca respectively, caused 100% of mortality at 12 and 24 hours in contrast with seven isolations that caused only 70% of mortality.

Compsus viridivittatus (Coleoptera: Curculionidae) es una de las principales plagas de cítricos en Colombia. Las larvas consumen raíces y los adultos hojas, flores y frutos. Causa pérdidas por disminución del área foliar mayores al 50% en árboles jóvenes y entre 20-30% en árboles en producción. Con el propósito de conocer la preferencia alimenticia y de oviposición en variedades comerciales, se utilizaron seis variedades de cítricos: naranja valencia Citrus sinensis, naranja sweety C. sinensis, mandarina arrayana C. reticulata, lima ácida tahití C. latifolia, lima ácida pajarito C. aurantiifolia y patrón volkameriana C. volkameriana. Se evaluó el consumo foliar por medio de ensayos de libre escogencia y no libre escogencia. La preferencia de oviposición se determinó con no libre escogencia. C. viridivittatus se alimentó de todos los materiales evaluados. Con libre escogencia, mostró preferencia por naranja valencia (644 mm²) y un menor consumo en mandarina (44 mm²). Sin libre escogencia, no se detectaron diferencias significativas en los materiales evaluados. Una mayor oviposición (37 huevos) se presentó cuando C. viridivittatus se alimentó sobre lima ácida pajarito, siendo significativamente menor en lima ácida tahití (9 huevos). Los resultados obtenidos en este estudio contribuyen al direccionamiento de los programas de manejo integrado que permitan la reducción de las poblaciones de C. viridivittatus.

Compsus viridivittatus (Coleoptera: Curculionidae) is one of the key pests of citrus in Colombia. Larvae consume roots and the adults leaves, flowers and fruits. It causes losses by decreases in leaf area greater than 50% in young trees and 20-30% in production trees. To determine feeding and oviposition preferences in commercial varieties, six varieties of citrus were used: valencia orange Citrus sinensis, sweety orange C. sinensis, arrayana mandarin C. reticulata, tahití lime C. latifolia, bird lime C. aurantiifolia and volkameriana rootstock C. volkameriana. Leaf consumption was evaluated through no-choice and free-choice trials. Oviposition preference was determined through no-choice trials. C. viridivittatus fed on all of the materials evaluated. In free-choice, C. viridivittatus showed preference for valencia orange (644 mm²) and lower consumption in mandarin (44 mm²). In no-choice, no significant differences were detected in the evaluated materials. The greatest oviposition (37 eggs) was observed when C. viridivittatus fed on bird lime, being significantly lower in tahití lime (9 eggs). The results obtained in this study contribute to the guiding of integrated pest management programs that allow for the reduction of C. viridivittatus populations.

A new trypanosomatid species, Blastocrithidia cyrtomeni, is herein described using morphological and molecular data. It was found parasitising the alimentary tract of the insect host Cyrtomenus bergi, a polyphagous pest. The morphology of B. cyrtomeni was investigated using light and transmission microscopy and molecular phylogeny was inferred from the sequences of spliced leader RNA (SL rRNA) - 5S rRNA gene repeats and the 18S small subunit (SSU) rRNA gene. Epimastigotes of variable size with straphanger cysts adhering to the middle of the flagellum were observed in the intestinal tract, hemolymph and Malpighian tubules. Kinetoplasts were always observed anterior to the nucleus. The ultrastructure of longitudinal sections of epimastigotes showed the flagellum arising laterally from a relatively shallow flagellar pocket near the kinetoplast. SL RNA and 5S rRNA gene repeats were positive in all cases, producing a 0.8-kb band. The amplicons were 797-803 bp long with > 98.5% identity, indicating that they originated from the same organism. According to the sequence analysis of the SL-5S rRNA gene repeats and the 18S SSU rRNA gene, B. cyrtomeni is different from all other known species or isolates of Trypanosomatidae. Both analyses indicate that among known species, it is most closely related to Blastocrithidia triatomae.