Date of this Version
JOURNAL OF INVERTEBRATE PATHOLOGY 41. 179-183 (1983)
The pathology and infectivity of an RNA virus infectious to Trichoplusia ni larvae was investigated. The enzyme-linked immunosorbent assay (ELISA) and weight depression were used as criteria for virus concentration in larval homogenates and live larvae, respectively. Infected larvae were severely stunted, weighing as little as 13 times less than uninfected individuals of the same age , yet appeared normal morphologically. The virus was found to cause only slight mortality at high concentrations. Infected larvae displayed the pathological stunting response down to a dose of 0.1 ng of virus. Larvae infected with doses 100 times lower did not show the weight response but such inapparent infections were detectable by ELISA. Because of these subtle gross pathological symptoms, particularly at low levels of infection, infected individuals could easily remain undetected in a group-reared colony.