Agricultural and Forestry Ministry (MAF) staff have found a new fungus in the North Island that attacks carnations.
MAF is investigating how far the downy mildew (Peronospora dianthi) has spread and how it got into New Zealand.
Severely infected plants have stunted growth with a deceptive profusion of shoots at the base
of the plant, giving a bushy appearance, MAF spokesperson George Gill said in a statement.
MAF had contacted commercial growers and asked them to notify it if they saw the disease.
The fungus produces two spore types; the short-lived conidia found on the underside of leaves, and the other more resilient oospore, which can live several years in the soil and is produced internally in rotting leaf tissue.
"Downy mildew is an unwanted organism in New Zealand and has the potential to damage susceptible varieties if environmental conditions are favourable," Mr Gill said.
- NZPA
