**3.2 Genus:** *Pseudomonas*

Members of the genus *Pseudomonas* are pathogenic aerobic bacteria that are naturally widespread in the environment [63]. Their wide occurrence has been attributed to their great deal of metabolic diversity and as a result, ability to colonise a wide range of niches. One of the most studied members of the group is *Pseudomonas syringae*. Angular leaf spot caused by *Pseudomonas syringae* pv. *lachrymans*, is common to almost every cucumber growing area of the world [64].

#### *3.2.1 Angular leaf spot*

Angular leaf spot is one of the serious diseases which primarily affects cucumber. The infection can affect the quality of fruit produced by inflicting up to 37 and 40 per cent reduction in fruit number and fruit weight, respectively in addition to rendering some fruits totally unmarketable [65]. At the initial stage, the symptoms appear on leaves in form of small, water-soaked lesions which later enlarge. Older lesions become angular as they enlarge and encounter veins. The infected tissues often dry and fall. The leaves are left with torn-irregular-shaped holes. In Africa, angular leaf spot disease was identified on cucumber seedlings raised from infected seeds in Egypt, with disease incidence of 98 per cent [66]. Different isolates of *P. syringae* pv. *lachrymans* from Egypt are also reported to induce wilting, besides the typical angular leaf spots, within 3 to 6 days of inoculation [67].

#### *3.2.1.1 Management of Angular leaf spot*

Angular leaf spot disease can be effectively managed by planting disease-free seeds. Additionally, planting field should have good drainage system to avoid any form of contact from neighbouring cucurbitaceous fields. Crop rotation with noncucurbits and complete removal of crop remains after harvest are helpful.
