Black spot, also known as scab or freckles, is a common disease in apple and pear trees that is caused by a fungal infection. Black spot can ruin an entire crop as fruits displaying black spots are not appealing in the marketplace, making the sale of infected fruits impossible
Black spot, or scab, is different when it comes to separate fruit varieties. Black spot can be found on peaches, cherries, plums, apricots and other "stone" fruits that have a pit. Black spots on stone fruit are caused y the fungus Cladosporium carpophilum, while those on apples are caused by Venturia inaequalis.
What it Looks Like
Look for black, raised spots on the fruit that look like lesions. The inside of the fruit might be exposed, making it susceptible to further attack by dangerous fungi. The branches and leaves of the tree may be infected, causing dark patches that are velvety to the touch. If the disease has been around all season, the spots will be brown, with a dark, black halo surrounding the area.
Black spot thrives in wet areas where it is humid and fungus is given the opportunity to grow. Higher temperatures with long, consistent rains will bring about the humid conditions that help this fungus thrive.
Black spot on fruits is a common occurrence around the world and can be found in most continents. Black spot is especially prevalent in Australia and New Zealand, where the temperature makes the trees vulnerable.
Control of Disease
Control black spot by spraying your fruit trees with fungicide. Fungicide is best applied in the spring before the fungus is given an opportunity to grow. Two main types of fungicides can be used: protectant fungicides such as Dodine, Chorus and Scala, and curative fungicides such as Nustar, Systhane and Score.