Farmers plant up to 3 crops a year on the same soil and even with crop rotation, the build-up of soil-borne diseases and eelworm infestation cannot be controlled effectively. Fumigation eradicates all soil pathogens and specifically plant parasitic eelworm.
Strawberry farmers fumigate before every planting due to strawberry plants being very susceptible to root diseases. The input cost for strawberry farming is very high and fumigation is recommended to maximise production and minimise risk.
Flower farmers fumigate to ensure maximum production. Rose farmers also have problems with replant disease when they re-establish roses on soil that was previously planted with roses. Fumigation is needed to rectify the problem. Proteas are very susceptible to phytophthora and other root diseases and replanting on soils where proteas were produced before, will result in poor growth and production. Fumigation of potting soil for nurseries is recommended and is good practice.