Ask the Plant Doctor! How to prevent new papaya leaves from dropping
Do you have a question about plants or how to maintain your garden? Send your questions to the Plant Doctor! Email your questions to lifestyle@thestar.com.my with "Plant Doctor" in the subject field. Questions may be edited for brevity and clarity.

Q: After one year, my papaya tree suddenly lost all of its new leaves, like it dried out. Please advise. – Tom Bachmann

The problem is most likely a deficiency of calcium (Ca), boron (B), or both.

However, B deficiency is more easily recognised by its impact on fruits, causing deformation and cracking.

In addition to Ca and B, deficiencies in zinc (Zn) and manganese (Mn) may also lead to the distortion of young leaves.

These four nutrients are essential for cell division, growth and metabolism, which is why their deficiency symptoms tend to appear in new or young growth.

Soil and leaf tissue tests are necessary to accurately determine the specific nutrient deficiencies. However, in the absence of laboratory testing, the following remedies can be applied.

1. For Ca deficiency, apply gypsum, lime or calcium nitrate to the soil. The application of sulfur should be avoided, as it is sometimes mistakenly believed to be equivalent to lime.

2. For B deficiency, apply borax or other boron supplements, carefully following the instructions, as it is easy to overapply B, which can lead to toxicity.

3. For Zn deficiency, apply zinc sulfate to the soil.

4. For Mn deficiency, apply manganese sulfate as a soil amendment.

Alternatively, you can apply a single “all-in-one” compound fertiliser that includes Ca and micronutrients such as B, Zn and Mn.

If fertiliser has been recently applied, it is crucial to avoid over-fertilisation, as excess nutrients can cause leaf damage.

Always follow the instructions provided carefully and water thoroughly after applying the fertiliser.

Be cautious not to overwater, as this can lead to waterlogged or saturated soils.

Assoc Prof Dr Christopher Teh heads the Department of Land Management, Faculty of Agriculture, Universiti Putra Malaysia. His field of specialty is in soil and water conservation. The views expressed are entirely his own.
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Why does a papaya tree lose its new leaves? The Plant Doctor is here to offer some advice.