Scouting for viruses: Impatiens necrotic spotted wilt virus
Editor’s note: This article is from the archives of the MSU Crop Advisory Team
Alerts. Check the label of any pesticide referenced to ensure your use is
included.
Pathogen: Impatiens necrotic spotted wilt virus (INSV). (view photos)
Hosts include: Ajuga, Aster, Bracteantha, Camp-anula,
Delphinium, Dianthus, Digitalis, Echinacea, Gaillardia, Gaura, Heuchera,
Hosta, Leucanthe-mum, Lobelia, Lysimachia, Monarda, Oenothera,
Penstemon, Phlox, Platycodon, Primula, Salvia, Scabiosa, Sedum,
Tradescantia and Veronica.
Symptoms: Symptoms vary depending on the host but may include
necrosis and spotting, ringspots, mosaic, mottling, distortion of new
growth, stunting and plant death.
Spread: INSV is spread by western flower thrips. Once a thrips
acquires INSV, it can vector the virus to susceptible hosts it feeds on
throughout its lifetime. The pathogen can also be spread by sap
transmission. Plants can be infected and show no symptoms; the virus can
be spread from these plants. INSV can overwinter in the roots of
infected plants.
Management: Scout incoming plant material for signs of disease
and for thrips. Susceptible plants should be scouted regularly for
thrips (see thrips section for more information). Avoid intermixing of
more and less susceptible crops within the same greenhouse. Also avoid
intermixing seed- and cutting-propagated crops. Eliminate weeds from the
propagation area. Immediately remove symp-tomatic plants from the
growing area. Diagnostic testing can be done by a plant diagnostic lab
or at the growing facility with testing strips available from plant
diagnostic companies.