Sclerotinia
rot :essential data |
Disease Name,
Other Names, Crops
Affected Causative Agent, Synonyms,
Description of the Agent Symptoms,
Prevention and Treatment
Other
Comments |
| Disease name |
Sclerotinia
rot |
| Other Names |
- Blossom blight
- Cottony rot
- Crown rot
- Drop
- Pink rot
- Water soft rot
- White mold
- White rot
|
Causative Agent
|
Sclerotinis sclerotiorum |
| Synonyms |
- Hymenoscyphus sclerotiorum,
- Peziza sclerotiorum,
- Sclerotinia libertiana,
- Sclerotium varium,
- Whetzelinia sclerotiorum
|
| Crops Affected |
Extremely wide range of crops including:
- cabbage
- beans
- citrus fruits
- celery
- coriander
- cucumber
- lettuce
- melon
- squashes
- soybean
- sunflower
- tomato
|
| Description of the Agent |
Sclerotonia
sclerotiorum is an ascomycete or sac fungus, so called because
the spores arising from a sexual cross (ascospores) mature in structures
called asci in a sac-like structure called a perithecium. It overwinters
in the soil using a refractory structure called a sclerotium. Unlike
many other ascomycetes, conidia (asexual spores) are not significant
in the distribution of the fungus. Germination begins when conditions
are relatively warm (>10°C) and humid. The sclerotium can germinate
in one of two ways after wet weather. The commoner form is called
carpogenic germination because it produces a reproductive structure
called an apothecium which bears ascospores. The dispersed ascospores
infect the developing plant with the symptoms depending on the plant
infected. The sclerotia can survive many years in the soil and germinate
many times. Alternatively, it can germinate directly into a mycelium
that attacks the plant directly. |
| Symptoms |
Symptoms can depend on the plant infected and the mechanism of
infection. Common symptoms include water-soaked spots on fruits,
stems, or leaves, petioles with altered morphology. The watery spots
enlarge and develop a cottony white mass that converts the plant
to a slimy, wet mass that produces abundant sclerotia.
In some plants, the symptoms are described as dry. The plant develops
brown lesions that coalesce and circle the plant. Everything above
the lesion wilts and dies
|
| Prevention and Treatment |
Treatment includes good cultural practices such as taking care
to avoid planting susceptible crops in poorly drained soils, low
planting densities and weeding between crop rows. Resistant strains
of susceptible crops are unknown. Infected fields should be planted
with non-susceptible crops, such as cereals for at least three years.
There are some fungi that are parasitic on Sclerotinia and that
can be used to control it. The most effective of these is Coniothyrium
minitans, but none have been turned into a practical treatment.
Chemical control can include soil fumigation, which is considered
an effective control method. Some fungicides, including benomyl,
are effective in some crops, but not all.
|
| Other Comments |
S. sclerotiorum
is to all intents and purposes world-wide in distribution and is most
prevalent in cool moist regions. It is known to affect over 360 species
in 64 families. |
|