Rotting of tissue
(usually the parenchyma) by the activities of a pathogen on the
middle lamella of cell walls. The cells become separated but
retain their shape for some time. Soft-rot Fungi are capable of
decomposing the cellulose and hemicellulose portions of wood;
most soft-rot also partially degrade lignin; these species are
most common in moist substrate
Underground symptoms include: The soft rot appears as a
soft, watery, and slimy decay of the a plant roots, lesions can
be as small as a single eye or involve the entire root. The
decay rapidly consumes the core of the roots, often leaving the
epidermis intact. The rot is extremely soft and colourless.
Although rot of the soft-rot bacterium is relatively odour free,
secondary organisms usually cause a foul smell.
Aboveground symptoms include: a general yellowing,
wilting, and collapse of the foliage. Lesions range from light
brown to colourless. Stems still get very mushy and hollow and
may be filled with mucilaginous slime. Often this disease is a
secondary infection associated with stem infections by late
blight.
Contamination: The
pathogens enters plants through various kinds of wounds. Soft
rot is most often associated with moist, cool conditions and
standing water resulting from poor drainage. The pathogens can
rapidly spread with rain or irrigation and by insects. The
principal source of inoculum is contaminated plant. The bacteria
can be spread by handling contaminated plants.
MANAGEMENT:
1. Provide good drainage
2. Avoid plant injuries and practices that could wound roots..
3. Minimize the bacterial contamination (Purchase plants free of
bacterial soft rot damage).
4. Sanitize and disinfest handling equipment.
5. Avoid injuring plants and allow cut plant to heal before
planting.
6. Avoid planting in overly wet substrate.
7. Avoid over-irrigation during warm months of the year.
8. Keep plants dry during the winter rest month.
9. Provide adequate air flow to promote drying, particularly
when plants first enter winter rest.
10. Avoid packing and storing wet plants.
11. Use systemic fungicides |
