Powdery Mildew - Apples

Podospara leucotricha

Powdery mildew (Podospara leucotricha) can be a serious disease of apples in drier areas of New Zealand. Powdery mildew usually attacks young leaves, shoots and flowers with severe infestations stunting trees. Seen as whitish felt patches of spores more commonly on the undersides of leaves but can spread to cover the whole leaf.

Related Pests

Brown Rot

Monilinia fructicola

Brown rot (Monilinia fructicola) is the most common and destructive disease of stonefruit crops in New Zealand. Obvious symptoms are brown circular spots on fruits which enlargen as a firm, dark-brown decay over the fruit surface often producing a brown –white sporulation mass. Brown rot is more problematic in wetter seasons.

Black Spot

Venturia inaequalis

Black spot (Venturia inaequalis) is a serious disease for New Zealand apple growers. Also known as apple scab, if not adequately controlled it can result in massive losses of marketable crop. Typical symptoms are circular black spots on leaves and fruits. On fruits the spots can coalesce resulting in cracks and rots. Black spot infection and spread is favoured by wet and mild weather. A similar but different species, Venturia pirina causes black spot in pears.

Fireblight

Erwinia amylovora

Fire blight is a devastating bacterial disease (Erwinia amylovora) of pears but can also attack apples. Symptoms of infection are well named with wilting foliage that has a black “burnt” look. Typically seen on young, vigorous growth. Moisture and mild temperatures during the blossom period favour infection.