---
title: "Can anyone tell me why this might be happening?"
description: "Can anyone tell me why this might be happening?"
url: "https://getplanta.com/community/Ktw8B5CcTlSQqDurUu87ug/fG06ogNvIQC3DNu9K3feTz"
community: "Pets and Plants"
author: "New Plant Mom🌿🌱"
published: "2026-05-30T13:57:49.534255Z"
language: "en"
image: "https://images.getplanta.com/v1/resize/K8OLSXzdLDXGfix2F1y51lS8yom4W16ex6El1b9MMF0/3cq7bMhpRreY3eP6tKJSMA.webp?size=large"
---

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# Can anyone tell me why this might be happening?

_Posted by New Plant Mom🌿🌱 on 2026-05-30_

Can anyone tell me why this might be happening?

![Attachment 1 of 1](https://images.getplanta.com/v1/resize/K8OLSXzdLDXGfix2F1y51lS8yom4W16ex6El1b9MMF0/3cq7bMhpRreY3eP6tKJSMA.webp?size=large)

## 2 comments

### Kande commented on 2026-05-31

I think that could be one of two things:

Botrytis (grey mould) - a fungal infection that thrives in humid, poorly ventilated conditions. It typically appears as a brown patch with a slightly grey, powdery surface

Bacterial leaf spot - caused by overwatering, water sitting on leaves, or poor air circulation

What might help:

Remove the affected leaf entirely at the stem  
Check the soil isn’t staying too wet between waterings  
Avoid getting water on the leaves when watering  
Improve air circulation around the plant  
If it spreads to other leaves, you might wanna treat it with a diluted copper-based fungicide.

That's what I think anyway

### Nikiller commented on 2026-06-08

Begonias get fungal infections if the airflow around the leaves isn’t good enough, if the leaves start overlapping too much that tends to happen. Given how close that leaf is with the one underneath, I would either trim the plant to keep the leaves separated to allow airflow or find a way to separate them out without trimming. I have some of my begonia rex in a cloche to keep the humidity high but the leaves don’t have any overlap so fungus and rot can’t set in. Leaves are resilient on these as I bought these ones that had a large section of a few leaves trimmed off from the previous owner, and the leaf simply scabbed over the cut and kept its full color.

![Attachment 1 of 2](https://images.getplanta.com/v1/resize/lWuVoSXfm0mhpdFLVG6GWzRgcJdFWwQeXC12gWazwDk/rQOk8RXyTcS8E-RHb89mSg.webp?size=large)

![Attachment 2 of 2](https://images.getplanta.com/v1/resize/lWuVoSXfm0mhpdFLVG6GWzRgcJdFWwQeXC12gWazwDk/JQ0xUCyPQGWF7k33wghfCQ.webp?size=large)

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