Agriculture Reference
In-Depth Information
Importance
Red stele root rot is a key biosecurity threat to the
Australian industry.
Strawberry germplasm can only enter Australia as
plants in tissue culture that then undergoes post-entry
quarantine.
What to do if you suspect red stele root rot
This pathogen is a biosecurity risk to Australia. Any
suspected affected plants should be reported to the
nearest Department of Primary Industries or the Plant
Health Australia hotline (1800 084 881).
Fig 18.33 Close view of red stele root rot.
Source of infection and spread
The fungus survives in decaying organic matter, crop
residues and weed hosts. It also survives as sclerotia, which
are resistant to harsh conditions. The disease is more active
during warm weather.
Many cultivated plants are susceptible to
Sclerotinia
sclerotiorum.
Importance
The disease is rarely seen in strawberries in Australia.
Importance
This is a minor disease found occasionally in ratoon crops
and runner-production beds.
Management
•
Do not plant in frost-prone areas, or plant too densely.
Frost and high ground humidity predispose plants to
the disease.
Management
•
Use a preplant cultivation to help crop residues
decompose thoroughly.
Do not plant susceptible crops, such as cabbage or lettuce,
in areas where strawberries are grown, because sclerotia
can survive for several years in the soil.
•
Remove dead leaves from around strawberry plants.
•
Remove plant debris (e.g. dead leaves) from strawberry
crops.
•
Grow strawberries on plastic to reduce fruit contact
with the soil.
•
Clean implements before moving them from infested
to uninfested land.
•
Do not plant runners affected by sclerotium crown rot.
•
Use preplant fumigation (broad scale or localised), as it
may kill sclerotia.
•
Fumigate soil to reduce sclerotinia.
•
SCLEROTIUM CROWN ROT
■
Cause
The fungus
Sclerotium rolfsii
.
Symptoms
A sudden wilt and collapse of plants occurs. If the crowns
of infected plants are examined, a white fungal growth will
usually be seen on the leaf bases. Small, spherical resting
bodies form in the fungal growth. They are first white,
then brown and black. Fruit may also be infected,
developing an irregular, light brown soft rot.
Fig 18.34 Sclerotium crown rot in strawberry. Infected crowns
and roots cause the plants to collapse suddenly.
