Bacterial canker in vegetables

Infected plants and stems

Infected fruit

Infected leaf

Infected plants and stems close-up

Bacterial canker in stone fruit is caused by a different pathogen, Pseudomonas syringae pv. Syringae.

Cause

The bacterium Clavibacter michiganense pv. michiganense.

Symptoms

Raised corky spots on fruit, dead leaflets on one side of leaf and bark peels easily from stem.

How it spreads

Bacterial canker is usually introduced in seed. It also spreads in sap when planting, trellising and pruning, and off fruit.

It survives on weed hosts and un-decomposed crop residue in the soil.

Crops affected

Tomato, capsicum, chilli and capsicum.

Control

Use disease-free seed. If unavailable, hot water treat the seed to reduce the amount of bacterium. Prepare ground early so there is no un-decomposed plant residue. Avoid handling affected plants. Wash hands regularly in a 10% TSP solution.

If bacterial canker was severe in the crop, dip or spray trellis wires and posts in a 2% formalin solution or dairy disinfectant products, then oil wire to prevent rusting.

Chemical registrations and permits

Check the Australian Pesticides and Veterinary Medicines Authority databases for chemicals registered or approved under permit to treat this disease on the target crop in your state or location. Always read the label and observe withholding periods.