How to recognise it
Generally the first symptoms to be noticed are a yellowing and wilting (sometimes very suddenly) of the foliage, which may also be smaller than it normally is. Flowering and fruiting may also be reduced.
On closer inspection a blackening of the roots and stem base will be found. This can include feeble, decayed roots, decay at the tips of the roots and dark patches on the roots and stem base.
Why it’s a problem
Since the disease is not normally noticed until the damage is done (ie when the roots have rotted and are failing to provide sufficient water to the upper parts of the plant) the plant will not survive. It should be removed and destroyed.
The fungus can survive in the soil as spores, resting bodies or mycelium, therefore it is able to infect new plants planted in that area, even if the original, diseased plants have been removed.
Where you are likely to find it
Can be found on a wide range of herbaceous plants, including asparagus, glasshouse carnations, chrysanthemums, glasshouse lettuces, lilies, lilies of the valley, lupins, narcissi (daffodils), peas, beans, primulas, radishes, saintpaulias, strawberries, sweet peas, tomatoes, tulips, violas and zantedeschias.
How to prevent it
Plants growing in stressful conditions (eg too much heat, overwatering or underwatering) are more likely to succumb to root and foot rots, so it’s important to maintain good growing conditions. Ensure good hygiene, particularly of pots and trays, where you suspect the disease has been present.
If you are watering from water butts then make sure these are regularly cleaned. If you have had a problem with root and foot rots in the past you may prefer to use mains water instead for watering plants in your greenhouse.
How to get rid of it
Badly affected plants should be removed and destroyed. Improve the growing conditions (eg water levels, drainage, feeding, pH levels) to reduce the risk of future attacks. Employ crop rotation where possible, particularly where peas or beans are affected, although a 5 year rotation is necessary to be sure of avoiding reinfection. Digging in the remains of brassicas is said to offer some protection against the disease accumulating in the soil.
If it occurs in a greenhouse then ensure that all containers and equipment are thoroughly sterilised before further use, and use clean compost.
Is it good for anything?!
No.
Other useful information
There are various, more specific, diseases which come under the broad heading of foot and root rots:
- Damping-off
- Beetroot black leg and dry rot (Pleospora betae)
- Brassica canker, black let and dry rot (Leptosphaeria maculans)
- Celery root rot (Phoma apiicola)
- Lawn turf rots
- Dollar spot (Sclerotinia homeocarpa)
- Ophiobolus patch (Gaeumannomyces graminis)
- Red thread (Laetisaria fuciformis)
- Snow mould (Monographella nivalis)
- Fairy rings (Marasmius oreades)
- Onion white rot (Sclerotium cepivorum)
- Potato black dot (Colletotrichum coccodes)
- Potato black leg (Erwinia carotovora spp. atroseptica)
- Potato stem canker and black scruff (Rhizoctonia solani)
- Sclerotinia disease (Sclerotinia sclerotiorum)
- Strawberry crown rot (Phytophthora cactorum)
- Strawberry red core (Phytophthora fragariae var fragariae)
- White root rot (Rosellinia necatrix)
