Virus transmission in orchids through the feeding damage of Australian cockroach, Periplaneta australasiae .

摘要

The project goal was to demonstrate the possibility of orchid virus transmission by a chewing insect, the Australian cockroach (Periplaneta australasiae) under controlled conditions. The experiments were housed in aluminum frame screen cages to contain the cockroaches. Two plants were placed in each cage: an orchid that tested positive for orchid virus and a young clone of Oncidium Sweet Sugar 'Kalender' that tested as virus free. Australian cockroaches were introduced into four of the cages. Two cages were used as controls containing the above plant material, but with no cockroaches. Approximately one third of the Australian cockroaches used were "wild" caught in a nearby conservatory and the rest were purchased from a commercial supplier. The cockroaches were communally housed for 1 week. We assumed that any of the wild-caught cockroaches that carried an orchid virus would distribute the virus particles by mutual grooming. The Australian cockroaches were housed with the plant material until sufficient feeding damage was observed. At that time, the orchid virus testing was repeated on the Oncidium Sweet Sugar 'Kalender'. Samples of new growth tissue were initially tested at a commercial laboratory and were subjected to an orchid virus screen that identifies nine viral agents known specifically to orchids. Test results were negative for virus presence. Four weeks after feeding damage was observed, testing was repeated. Tissue from the feeding sites was tested for presence of CymMV and ORSV with Agdia's immunoStrip kits. Two sites were faintly positive for CymMV. Testing was repeated 18 weeks later with Agdia's immunoStrip kits and the same sites showed a strong response for both CymMV and ORSV.