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Boron deficiency in pome fruits e.g Apple,Pear (External cork/Internal cork)

Posted on | June 6, 2015 | No Comments

Boron deficiency in pome fruitse.g Apple,Pear (External cork/Internal cork)

-Brown tissue occurs near the core
-Cracks may develop in fruit
-Stem and leave symptoms

Boron (B) is required by plants in a very small quantity by apples & pears that’s why it’s said to be a trace element (TE), its deficiency can cause various disorders. Boron (B) deficiency can be observed mostly in moisture or water logged soils and also on sandy or dry soils. Symptoms develop on fruit and leaves.


  • Internal cork

Fruit affected by internal cork often show no external symptoms but can be seen when fruit are cut. Deficiency can be usually seen after 6-8 weeks after petal, in Himachal Pradesh, May end when plant face dry conditions. Round soaked mark appear most of the flesh. The spots dry out and turn very dark from the centre outwards, finally forming brown spongy lesions, often with a greenish halo. Lesions in the core region sometimes run together, dry out and form cavities. The brown tissue normally occurs closer to the core than the skin.

  • External cork

It is more likely to occur if boron deficiency occurs early in the growing season. It causes rough marks and makes to appear as fruit matures. Rough brown or reddish spots may occur which later crack & the skin dries up, leaving a rough corky fruit skin. Dark brown to greenish-black lesions with a green border occur on or just beneath the skin, mostly in the depressions, it later become dry and corky.

  • Stem and leave symptoms

Boron (B) deficiency occurs in middle of season. Leaves oBoronn fresh growth become distorted and turn yellow with red veins. Small brown necrotic areas develop at the margins and leaf tips. The new shoots may die from the new growth tip. If mid-season deficiency is not treated before dormancy, dieback can develop in spring. In spring dieback, buds fail to develop. Affected twigs die back and an abnormal number of small branches may develop from below the dead portion. Dieback can also be a symptom of problems other than boron deficiency. Boron deficiency can also lead to rosette symptoms in leaves. Leaves become dwarfed, thickened and brittle and are found on much shortened twigs. Zinc (Zn) deficiency can also cause leaf rosettes, but the presence of corky lesions in fruit will distinguish between the two.

In apples the fruit symptoms of boron (B) deficiency can often be confused with calcium (Ca) deficiency, especially where cracking is not visible or at initial stage.


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