Cyclamen disease management

Cultural control measures will reduce the development of disease and the need for fungicide inputs and are an essential part of any disease management program.

Pre-cropping

• Clean and disinfect standing areas, including capillary matting (where reused). If fusarium wilt or phytophthora root rot occurred in the previous cyclamen crop, or if any of the root diseases occur at a high level, replace the matting
• Cover water storage tanks to prevent contamination by pathogens such as Pythium species and Phytophthora species and test the water source for pathogens
• Cover open bales, bags, or bulk growing media to prevent contamination by dust or crop debris containing resting spores of root pathogens

During cropping

• Consider using a growing medium containing up to 40% composted pine bark or wood fiber, with nutrition adjusted accordingly
• Ensure young plant specifications complement your method of planting; long petioles are often damaged by planting machines
• Plant carefully to reduce wounding and ensure that the top of the corm is well above the growing medium surface to reduce the risk of bacterial soft rot
• Irrigate regularly but not to excess. Irregular watering can lead to cracks developing in the corm through which bacterial soft rot can enter. Wet growing media will favor the development of black root rot, Pythium, and Phytophthora
• Reduce the spread of Botrytis, Colletotrichum, and Fusarium spores by water splash, as well as stopping periods of persistent leaf wetness, by using a sub-irrigation system
• Where water is recirculated, water treatment by chemical or biological filtration is likely to be necessary to remove pathogens
• Avoid high nitrogen feeds which lead to soft growth and increased disease susceptibility
• Avoid damaging foliage and flowers, increasing the susceptibility to Botrytis
• Avoid pot thick spacing and increase airflow to reduce periods of high humidity and prolonged leaf wetness. Good air movement will help to harden plant growth and reduce petiole length
• Use glasshouse shading and/or shade screens to help minimize plant stress
• Avoid holding autumn pack bedding cyclamen past their optimum stage: Botrytis can become a serious problem due to the dense foliage and fallen flowers

Environmental control

• Use ventilation fans and shading to reduce very high temperatures. At 20–25ºC or higher, the risk of anthracnose, bacterial soft rot, and fusarium wilt increases, as well as a risk of delayed crop establishment
• Closely monitor and reduce humidity levels by a combination of plant spacing, ventilation, fans, and, later in the growing season, heat boosts. These cultural techniques will help to minimize the incidence of Botrytis
• Avoid sudden drops in air temperature at flowering as these can lead to condensation so increasing Botrytis risk

Nursery hygiene 

• Ensure that senescent leaves and flowers are removed promptly, especially at the later stages of crop development
• Monitor and control pests such as thrips and aphids, as well as sciarid and shore fly which may spread spores of Colletotrichum species Fusarium species, Pythium species, and Thielaviopsis species
• Promptly remove diseased plants to limit secondary disease spread. Carefully bag plants before removal to avoid spreading spores of Botrytis or Fusarium
• Ensure that diseased material and other crop debris is removed off-site or kept in covered skips or heaps, well away from production areas, prior to disposal.

AHDB