Actividad ovicida y larvicida de extractos acuosos de Pluchea sericea y Artemisia tridentata en Haemonchus contortus

El objetivo fue evaluar la actividad ovicida y larvicida de extractos acuosos de hojas de Pluchea sericea y Artemisia tridentata sobre Haemonchus contortus. Se evaluaron concentraciones de 100, 75, 50, 25 y 12.5 mg mL-1 de cada extracto. Se tuvo diferencias signicativas (p 0.05) para todas las concentraciones en la inhibición de la eclosión de huevos y mortalidad larval de H. contortus. La dosis de 100 mg mL-1 redujo la eclosión larvaria en 100 y 96.30%, con mortalidad larvaria del 92.67 y 89.33% para P. sericea y A. tridentata, respectivamente. La CL50 fue de 23.21 y 23.26 mg mL-1 para la inhibición de eclosión de huevos, para la mortalidad larvaria se tuvo una CL50 de 20.36 y 27.18 mg mL-1 para los extractos de P. sericea y A.tridentata, respectivamente. Los extractos acuosos de hojas de P. sericea y A. tridentata controlan los estadios de huevo y larva de H. contortus.

Arrowshaft-straightening with a Grooved Stone

Not long ago at Tonto National Monument, Arizona, I discussed with Erik Reed and Lloyd Pierson, National Park Service archaeologists, the grooved stone “arrowstraightener” or “arrow-smoother” and its presumed uses. At that time I held serious doubts that this well-known object had ever had any place in the making of arrows. As a fletcher of some 20 years' experience, I had taken particular note of Pima fletchers and the manner in which they worked their shafts, and was impressed by the ease with which they took rather crooked sticks and made them straight and serviceable as arrows. These sticks were always of arrow weed, or specifically Pluchea sericea. Salt River Valley had almost no reed cane (carrizo; Phragmites), and I never saw it used. I note also the fact that no grooved stone was used in straightening Pima arrows.