- Antimicrobial additives to the irrigation water
- Chlorine (up to 200 ppm)
- Chlorine dioxide (100 ppm)
- Calcinated calcium (0.4%, w/v)
- Ozonated water (9 ppm)
- Combination of ozonated water 0.3 to 0.5 pm) and gaseous ozone (0.2 ppm)
- Thyme oil alone or with chlorine dioxide and ozonated water
- Acidified sodium chlorite (1,200 ppm)
- ? No intervention was highly effective