EPIDEMIOLOGY OF FUSARIUM WILT DURING PROPAGATION OF CARNATION
In these conditions, the cuttings harvested in january on symptomless plants are Fusarium free, at least up to 15 may. After this date, the mycelial development in the plant precedes the symptoms.
During rooting in perlite, the fungus in a cutting infected at its base sporulates and the conidia may spread in the substrate to the 24 surrounding cuttings. The plants produced by these cuttings will reveal symptoms more or less quickly according to the nature of soil and inoculum level in rhizosphere. The slight infection is probably the cause of very late attacks which can even appear a year after plantation.
This work has allowed a certification method of the cuttings to be set up. Every culture for which the cumulative rate of the diseased plants does not reach one in a thousand the yielded cuttings are considered essentially Fusarium free.