Datura Genus Weeds as an Epidemiological Factor of Alfalfa mosaic virus (AMV), Cucumber mosaic virus (CMV), and Potato virus Y (PVY) on Solanaceus Crops

Abstract

Plant samples of jimsonweed (Datura stramonium L.) and thornapple (D. ferox L.) were collected to determine the presence of Cucumber mosaic virus (CMV), Alfalfa mosaic virus (AMV), and Potato virus Y (PVY) in Santiago, Chile (33º34’ S lat, 70º38’ W long, altitude 625 mosl), using double stranded RNA (dsRNA) analysis and ELISA. Both weeds were positive to the three types of virus with a percentage of infection ranging from 20-30% except for PVY infection in D. stramonium with an incidence of 5%. Under controlled conditions, the aphid Myzus persicae (Sulzer) transmitted CMV from D. ferox to tomatoes (Lycopersicon esculentum Mill.) and sweet peppers (Capsicum annuum L.), but did not transfer it to potatoes (Solanum tuberosum L.). Seeds of positive D. stramonium and D. ferox plants did not transmit CMV, AMV or PVY. In the field, the presence of virus-infected Datura plants in the vicinity of the test crop plots and flight activity of aphid vectors was not correlated with the levels of infection of tomatoes, peppers and potatoes. Wind direction probably affected the ability of flying vectors to transmit viruses. Datura weeds, especially D. ferox, ought to be controlled not only because of economic losses produced by weed-crop competition, but also because they are alternative hosts of CMV, AMV and PVY. >From an epidemiological perspective, management of weed control ought to include not only D. ferox plants within the crop, but also plants surrounding the upwind edges of the field.