DISEASE

NAME
Bacterial Soft Rot
Erwinia species


Symptoms
Bacterial Soft Rot(Erwinia carotivora)infects the cell walls of the plant tissue causing the fluids to leak out making the areas soft and slimy. It commonly occurs at the base of the plant above or below ground level forming a soft dark patch and eventually the plant topples. It is not instantaneous and crops are infected during harvested they can rot in storage as the infection takes hold.

     

Soft Crown Rot (Pectobacterium carotovorum) is a bacterial disease that normally occurs during hot humid weather and is found in the soil and infects the roots and crown of the host normally through wounds. The symptoms are a rot that causes the plant to wilt and die and generates a strong offensive odour.

Source and Dispersal
It dwells in soil or in host plant and is dispersed on insects or animals from infected plants and can also be dispersed by water.

Favoured Conditions
It prefers warm moist conditions.
     
Affected Plants
It prefers succulent stems, buds, roots or fruit of a wide range of plants including vegetables, perennials and tuberous plants.

Caladiumspecies are venerable to several bacterial diseases that infect tubers, including (Pectobacterium carotovorum) and (Pellicularia rolfsii) both causes soft rot.

Cactusspecies particularly larger ones are infected by the Bacterial Blight(Erwinia carnegieana). This destructive disease produces small circular light coloured spots that are water soaked along the margins with the underlying tissues turning black. It then turns blackish splits open and oozes brownish fluid. Infected branches collapse and the disease spreads quickly through the plant.

Dahliaspecies may be infected by Tuber Rot (Pectobacterium carotovorum) that attacks stored tubers causing them to form brown soft rot.

Delphiniumspecies are infected with the Bacterial Soft Rot(Erwinia phytophthora) that causes the top of the plant to dry out, giving off a foul smell. The upper stems become soft and blackish, causing the plant to be stunted and eventually die to ground level.

Delphiniumspecies are infected by the Soft Crown Rot(Pectobacterium carotovorum) causing the death of the plant it also attacks Sansevieriaspecies causing them to rot at the base.

Aglaonemaspecies are infected by the Bacterial Blight((Erwinia carotovora) and (Erwinia chrysanthemi). Leaves with this infection form watery spots that disintegrate in time forming a hole in the leaf and root rot symptoms appear as the stems become mushy and a foul smelling. Cuttings with a root rot soon die and infected leaves should be removed. It is important to use a clean propagation material and irrigation systems that do not wet the foliage.

Orchidssuch as Cattleya, Cymbidium, Cypripedium, Dendrobium, Epidendrum, Oncidium, Paphiopedilum, Phalaenopsis and Zygopetalumspecies are infected by Soft Rot(Erwinia species).

Saintpauliaand Philodendronspecies are infected by Bacterial Blight (Erwiniaspecies) which forms brownish to black rot water soaked spots that can appear all over the plant.

Non-chemical Control
As a preventive measure cultivate the surrounding soil to improve drainage, aeration and minimise weed growth. Do not over water and allow the soil surface to dry before rewatering. When handling the plants pick a dry period and take care to minimise damage. Collected produce should be stored in a cool dry environment as the bacteria is inactive in temperatures below 4şC.
At first sigh of infection the plant should be removed and disposed off.

Chemical Control
There is no satisfactory chemical control. It is important to take preventive measures.
Note
Always read the label for registration details and direction of use prior to application of any chemicals.