Treatments for the control of black root rot in bedding plants and hardy nursery stock

Black root rot (Thielaviopsis basicola) affects plants from at least 15 families, causing root damage leading to reduced nutrient and water uptake, consequent leaf yellowing and potentially plant death.

Infection by Thielaviopsis basicola may be underestimated; symptoms are fully described and illustrated in the report. In Viola species, black root rot was reduced by Cercobin WG, Signum, three coded fungicides and one coded biofungicide; Prestop. None of the products tested were effective at reducing black root rot in Choisya. Fusarium oxysporum was isolated from roots of wilted and dying Choisya, but further work is needed to determine if this is what causes Choisya wilt.

To Improve control of black root rot (T. basicola) and increase the quality of container-grown ornamentals through the use of plant protection products and plant stimulants.

Project objectives:

1.  To determine the efficacy against black root rot and plant safety of some chemical plant protection products to Viola
2.  To determine the efficacy against black root rot and plant safety of some biological plant protection products and plant stimulants to Viola
3.  To utilise the results from work carried out under objectives 1 and 2 to select products for application to Choisya to protect against black root rot.
4.  To communicate the research results to the industry