Tomato leaf mould

Identifying Features
It usually becomes apparent on the lowest tomato leaves from early or midsummer. Purplish brown mould patches appear on the underside of the foliage - the upper surface bears yellowish patches. Lower leaves are attacked first.

Treatment
Remove some of the lower leaves. Disinfect entire greenhouse. If the problem isn't tackled, tomato yields are lower and the fungus can overwinter in the greenhouse and persist the following year.

Chemical
Spray infected plants with mancozeb.

Prevention
Ventilate the greenhouse, especially at night. Avoid splashing plants when watering