What is scab apple disease on apples & pears?
Apple scab is a disease that is produced by the fungus, “Venturia inaequalis”. The fungus is transmitted by airborne spores that can survive the winter with fallen leaves.Moist and warmer conditions in the spring cause the release of V. inaequalis’s spores which land on the surface of a tree, where a germ tube is formed through the plant’s cuticle. At this stage, a fungal mycelium forms, asexually producing more spores. These spores germinate on the plant, asexually producing more spores. Secondary infections then persist through much of the rest of the growing season.
In this disease, you can see prominent scab marks can be observedon the leaves of apple trees. These marks normally appear from mid-spring normally and stay until the time leaf falls in the Autumn.
Scab is a serious kind of disease which is not only limited to apple trees but can also attack some other trees such as Pyracantha, Sorbus, and Cotoneaster. A closely related fungus attack can also happen on pear plants which is also known as pear scab. This normally affects multiple pear varieties from ornamental and through to fruiting.
Scab can cause fruit and leaves loss because of untreated surface blemishing of leaves and fruits. It is mostly being caused in the areas where early summer and spring seasons are cool and moist. Fungal spores are carried by the wind or rain to the leaves, fruits, and flowers from the ground, with newly opened leaves and flowers are more susceptible to this problem.
Prevention Of Scab Disease On Apples And Pears
Although choosing a more resistant variety of trees can be an effective option to choose, it is also important to eliminate the current infection in a more effective way too.
Non-chemical means of treatment are limited to manual removal of affected fruits, leaves and shoots. Removal via this method will result in less fungus being available for the next growing season, however unless the trees are well isolated from each other, this treatment is of limited value owing to how easily the fungus is transmitted by the wind. As such, chemical means of treatment are preferred by the commercial grower. Copper oxychloride Demilidex is a highly effective fungicide supplied by African Pegmatite for the control of pathogens like Venturia inaequalis.
How it is used to treat the problem?
Copper oxychloride Demildex is applied in aqueous solution at up to 0.25 volume % (2,500 ppm), which represents an equivalence of approximately 50% metallic copper. Demilidex is applied at the early green tip stage on apples and the early to advanced green tip phase for pears.
Demilidex is supplied as a fine light green powder containing copper oxychloride at a concentration of 850 g kg-1. Copper oxychloride is the sole active ingredient. Particle size is 40% less than 2 μm and 95% smaller than 5 μm. Surface area is on the order of 30,000 cm2 g-1.
Many highly effective fungicides are manufactured with the use of scrap copper, however Demildex is produced from well refined, highly pure copper. The copper oxychloride is dissolved slowly in the moisture of the plant on the leaf in the presence of a weak organic acid. As the scab plant disease takes hold to a greater extent during rainy weather, copper in a small amount will be released on the surface of the plant which can inhibit or kill microorganisms’s reproduction, it is this which acts as the prevention mechanism against scab . Demildex copper oxychloride is a superior quality fungicide that provides encouraging results that controls the problem in a short time frame and will prevent fruit and leaves from more damage in a most effective way.
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