COMPARATIVE PATHOGENICITY OF NOSEMA ACRIDOPHAGUS HENRY AND NOSEMA CUNEATUM HENRY (MICROSPORIA: NOSEMATIDAE) FOR MELANOPLUS SANGUINIPES (FAB.) (ORTHOPTERA: ACRIDIDAE)

Abstract

AbstractNosema acridophagus Henry was shown to be more virulent than N. cuneatum Henry to 3rd-instar nymphs of Melanoplus sanguinipes (Fab.) following peroral inoculation with 1.0 × 106, 105, 104, or 103 spores/individual. The lethal time was dose dependent and significantly shorter and the lethal dose (LD50) was significantly lower in grasshoppers inoculated with N. acridophagus than for those inoculated with N. cuneatum. Grasshoppers inoculated with N. acridophagus died earlier and a smaller proportion survived to the adult stage compared with those inoculated with N. cuneatum. Nosema acridophagus was more infectious at the lower doses than was N. cuneatum; however, N. cuneatum reached an intensity of infection in host tissues which was 2–10 times higher. Both microsporidians appeared to have similar pathogenicity for both individually and group-reared M. sanguinipes.