Effects of carbon dioxide anaesthesia on the ability of the planthopper Laodelphax striatellus, to vector maize rough dwarf virus.

It has been suggested that anaesthesia with carbon dioxide can influence the feeding behaviour of the planthopper Laodelphax striatellus, a vector of plant viruses within the Reoviridae, the Rhabdoviridae and the tenuivirus group. We have studied the influence of CO, anaesthesia on the acquisition and transmission in seria1 passages of rnaize rough dwarf virus, a phloem-limited member of the Reoviridae, which is transmitted propagatively by L. striatellus. Anaesthetizing the insects before acquisition feeding significantly reduced (p < 0.01) the acquisition of the virus from infected barley and maize plants (from 47.37 % to 25.00 %). In seria1 passage infectivity tests using 3-day inoculation feedings, the 36 infettive hoppers not anaesthetized infected al1 the test plants of 5 passages. Four out of 52 insects failed to infect the test plants of the third passage when subjected to anaesthesia between the second and the third passage, although the four insects infected again the test plants during the fourth and fifth passages. Since 80% of anaesthetized insects died when starved for 3 days and the survival of insects was not significantly affected by anaesthesia during serial transfer, it is concluded that C0,-treatment can temporarily atTect the ability of the L. striatellus to acquire and transmit MRDV, and that this is not due to fasting during the acquisition or inoculation access.