Cabbage quality affected by disease, pests

A good gardener should inspect his crops routinely and root out enemies of his crops in order to get good yields.

In cabbages, several diseases and pests lower their quality and therefore shorten the shelf-life and become a health hazard to the consumer.

Common cabbage diseases in Uganda are black rot, cabbage ring spot and common pests found on cabbages include aphids and diamond moths.

Gideon Zakka an agronomist says if you are like a person who enjoys vegetable salads with mayonese, a diamond moth, or aphid in the salad would make you throw up! “Besides, these pests transmit several viral diseases to their hosts. Black rot disease in cabbages is caused by a bacteria Xanthomonas campestris”.

According to Zakka, the disease affects the plant at any age and at any time during its life. All members of the cabbage family including cauliflower and Brussels sprouts are affected. It is normally the upper parts of the plant which get infected leaves, stems. But turnips and radish that have fleshly roots are also affected by dry rot.

Common symptoms

-Symptoms of black rot in cabbages are V-shaped, chlorotic blotches at the margins of the leaves that progress towards the midrib of the leaf.

-The veins and veinlets (small branch of veins on the leaf) turn black.

-Later, all the affected leaf area turns brown and dry

-Herbert Kaweesi, a cabbage farmer in Janda in Zirobwe says the multiplying bacteria spread to other parts through the veins to the stem, other leaves, and down to the roots.

-The stem and stalks of the leaves appear healthy outside while infected inside, but when cut across they show a characteristic black ring and often small yellow slimy droplets of bacteria which give an offensive odour.

-Advanced spread of the infection causes a blackhead cabbage and odour comes out of the affected stem and stalk.

Control

The disease is very difficult to control but the following are some useful tips.

-It is best to plant seeds free from bacteria

-Practise crop rotation-plant different crops where you previously planted cabbages.

-Soak seed in sodium hypochlorine for 30 minutes before sowing

-Spray the cabbages with copper fungicide