Innovative strategies for the control of apple scab caused by Venturia Inaequalis
- Aroma Murtaza، Safa Khalid۔ University of Agriculture, Faisalabad۔
Apple tree is commonly called Malus domestica. Apple fruit is a delicious pomaceous fruit which belongs to Family Rosaceae, Genus Males
Except for the seeds the whole fruit including the skin is appropriate for human consumption. The inner core of the fruit that contains seeds, is not eaten and is discarded. Aphids and mildew are the common insects that attack on apple. In 20014, about 84.6 million tons of apples were produced worldwide. Pakistan is the world’s 10th largest country for apple production
Apples contain Dietary fibers and flavonoids antioxidants. Apples are rich in Iron, vitamin C and other Important Vitamins. They help to reduce the cholesterol level and retain the skin freshness. Apples are rich in polyphenolic compounds and vitamin B complex.
Symptoms of the Apple Scab
Olive green zones visible on the basements of leaves are the first indication of the disease. Leaves become twisted dwarfed and drop later in the season. Around the margins of the lesions sunken brown spores appear. Yellowing of leaves start and then they ultimately fall, cracks appear on infected fruit and lesions on fruit are almost rough-surfaced. Early infection may occur on the pedicel or on the calyx due to severe pedicel infection and hence, fruit drop occurs.
Venturia inaequalis overwinters in diseased leaves that have fallen to the ground within the dead leaf tissue producing fruiting bodies. On spring, these start to mature and produce spores (ascospores) that are discharged into air and carried to apple buds when the apple buds are in developing stage.
Management of the Apple Scab
Applying fungicides Scab infections may be prevented throughout the growing season and sanitation can be effective for managing apple scab. Scab-resistant varieties reduce this disease such as Purple prince and Royal rain drops. It’s important to discard or remove all dead leaves because the apple scab fungus mostly overwinters in dead leaves. Spray of Zinc and Urea reduce the disease incidence. Prune the tree, remove the infected or dead branches so that the air easily passes through the tree. The antagonist Cladosporium cladosporioides H39 was found to deliberately overcome sporulation of Venturia inaequalis during summer Scab epidemics and are driven by conidia, produced only on apple leaves. A biological control agent H39 has been tested in numerous European field trials during the last two years and found that it is effective against apple Scab.