**3. Bacterial diseases of cucumber**

#### **3.1 Genus:** *Erwinia*

The genus *Erwinia* comprises rod-shaped bacteria that are plant-pathogenic and plant-associated [59]. Bacteria in this group are related to *Escherichia coli*, *Shigella*, *Salmonella* and *Yersinia*. A typical member of this genus which affects *C. sativus* L*.* is *E. tracheiphila* which causes bacterial wilt of cucurbits in general.

#### *3.1.1 Bacterial wilt of Cucurbits*

Bacterial wilt, caused by *Erwinia tracheiphila* and vectored by striped cucumber beetle (*Acalymma vittatum* F.), is one of the serious diseases threatening natural and wild cucurbit crops. Cucumber is one of the most susceptible to the disease [60]. Bacterial wilt remains a major disease of cucurbits in South Africa [61]. Transmission occurs when an infected beetle creates wound during the course of feeding on a plant and defecates therein. The bacterium moves by free water into the xylem, which spreads and multiplies it. Disease symptom appears first on younger plants and these include discolouration of stem tissues and wilting of some or all the parts of the affected plant [62].

#### *3.1.1.1 Management of Bacterial wilt disease of cucurbits*

Disease management relies on controlling cucumber beetles, mainly through insecticide applications. Practicing crop rotation and planting cultivars that are less attractive or susceptible to striped cucumber beetles are also helpful.
