Boron Deficiency in Durian

Boron is an essential micronutrient for plants, including durian trees. As with other fruits, boron impacts growth and quality of the durian fruit. For example, boron positively interacts with sulfur which can help improve soil fertility and increase durian yield. Research by Mitali Mandal et al (2018), showed the interaction effect between boron and sulfur might be helpful in maintaining boron and sulfur in soil vis-a-vis in moderating some important biological indices in a most favorable state, which ultimately improved soil fertility with simultaneous increase in yield. Durian is a chloride sensitive crop and normally farmers apply sulfate of potash for potassium input. Good sulfur content in the soil enhances the production of volatile sulfur compounds in durian. This contributes to the distinct smell and taste of durian fruit.

Boron deficiency can have significant impacts on durian trees, affecting their growth, development, and fruit production. Signs and symptoms of boron deficiency in durian include:

  • Poor flowering and fruit set: Boron deficiency hampers the development and functionality of reproductive organs, leading to poor pollination and fertilization.
  • Abnormal fruit development: Fruit may be small, misshapen, or have uneven growth.
  • Cracked or split fruits: This occurs because boron plays a role in cell wall formation and elasticity. Without sufficient boron, the fruit's skin may not be able to expand properly, resulting in these types of defects.
  • Corky tissue: Durian fruit tissue appears dry, cork-like, and can negatively affect the fruit's texture and quality.
  • Leaf symptoms: Durian tree leaves may exhibit chlorosis, yellowing along the edges, and eventually necrosis or death of leaf tissue. The affected leaves may also become brittle or show signs of deformation.

When boron deficiency happens in durian it can also result uneven fruit ripening (UFR) which is characterized by:

  • Hardened, leathery aril
  • Whitish color
  • Odorless and tasteless pulp

UFR normally occurs when the fruits are about to ripen and remains invisible until the fruits are opened. D159 Monthong, D197 Musang King, and D24 varieties that have bigger pulp flesh will face a higher chance of UFR.

In addition to preventing UFR, boron encourages flower bud initiation as well as increases flower production and retention—all of which can increase fruit yield. Boron also plays a vital role in pollen tube elongation, and seed and fruit development. Boron deficiency can cause incomplete pollination.

Unfortunately, boron deficiency symptoms often reveal themselves once fruit yield has decreased. U.S. Borax recommends regular soil and tissue testing to ensure you are giving your trees an adequate supply of boron throughout their growing cycle.

Spotting Boron Deficiency in Durian Fruit

Applying boron

For every 1000 kg/tree of durian fruit removed from the tree, it is estimated that 4.4 kg/tree of boron is also removed from the tree (Diczbalis YA. et al 2005). Durian growers in Malaysia and Thailand apply the boron fertilizer Solubor® and a calcium mix as the foliar application during the flowering to fruiting stage. We suggest mixing Solubor with calcium 0.5-1g/L spray with spray volume dependent on the durian age profile and canopy management.

As an alternative, you can apply Granubor® and Fertibor® in direct soil application.

All three of these U.S. Borax products—Fertibor, Granubor, and Solubor—are OMRI® Listed products. As OMRI Listed, they are an appropriate fertilizer and soil amendment for organic crops that are boron deficient. OMRI is ISO 17605 accredited as a material review organization, so certifiers can accept the OMRI Listed Seal anywhere in the world.

In addition, U.S. Borax products are fully refined to remove impurities and heavy metals, including arsenic. Because the refining process removes arsenic and other heavy metals from the original ore, the final refined fertilizer product is pure and safer for agriculture use. This minimizes potential arsenic uptake by durian trees.

While boron is necessary for durian tree growth, an excessive amount can lead to toxicity and cause damage to the plant. It is crucial to provide durian trees with an appropriate and balanced amount of boron through soil amendments or foliar sprays. Application rates should be based on soil and tissue analysis. Consult with local agricultural experts or horticulturists for specific durian tree recommendations in your region.

U.S. Borax Products

15% Boron |  | OMRI Certified
Optimum product for suspensions

A fine crystalline borate ideal for NPK compound fertilizers and suspensions. Manufactured as free-flowing granules, Fertibor is easily handled and offers superior flow and consistency.

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15% Boron |  | OMRI Certified
Made especially for bulk blenders

A pure, 100% water-soluble micronutrient that meets boron demand during the growing season. Made especially for bulk blenders, Granubor helps to ensure uniform distribution in nutritional blends and in the field.

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20.5% Boron |  | OMRI Certified
Product of choice for foliar applications

A concentrated, highly soluble, and fast dissolving powder that is ideal for foliar and other sprays. With the highest concentration of boron in any approved product, Solubor is an economical choice for nutritional formulations.

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20.8% Boron
Boron for fertilizer manufacturing

This refined U.S. Borax product is made from the dehydration and fusion of borax. Depending on the grade, Anhybor can be used to produce boron-enriched compound fertilizers or to coat different fertilizer products, such as NPK blends with the aid of a binder.

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10% Boron
Solubor Flow
For fertigation or hydroponic growing

First and only aqueous suspension of sodium borate microcrystals.

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14.5% Boron | 29% Zinc
Perfect combination of zinc and boron

Because zinc and boron deficiency are widespread around the world, a product with both nutrients is a good fit in many regions. Zincubor brings these two important micronutrients together in one product.

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Calculate Your ROI

Soil Application (Suggested rates of application)

  Granubor Fertibor
LBS/ACRE 17.67 17.67
KG/HA 8.0 8.0

Foliar Application (Suggested rates of application)

Value in Use
Current Yield (Per Acre)
Expected Sale Price

U.S. Borax, part of Rio Tinto, is a global leader in the supply and science of borates—naturally-occurring minerals containing boron and other elements. We are 1,000 people serving 650 customers with more than 1,800 delivery locations globally. We supply around 30% of the world’s need for refined borates from our world-class mine in Boron, California, about 100 miles northeast of Los Angeles. Learn more about Rio Tinto.

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