How to treat Bouganvillea and Impatient with brown leaves and white marks?

[gs_p]

 

  

 

My bougainvillea seems otherwise quite healthy but some leaves are turning brown and crispy while some of them have these white marks.

Same with my Impatients ( it is flowering beautifully) but I have just noticed these white marks. I have checked the plants and don’t see any aphids, mealy bugs or spider mites. 
I cannot work out what could be causing this issue? 

Any advise would be great. thanks! 

[JacobZ]

Hi @Greg_r,

It looks like your plants are experiencing some issues from powdery mildew. Powdery mildew is a common fungal disease that appears as white, powdery spots on leaves, stems, and buds. It thrives in warm, humid conditions with poor airflow and can affect a wide range of plants, including bougainvillea and impatiens.

At first, you’ll notice small white or greyish patches on the leaves, which can spread quickly. Over time, the affected leaves may turn yellow, then brown and crispy as they dry out and die. While powdery mildew rarely kills plants, it weakens them, reduces flowering, and can make them more vulnerable to other issues.

To manage it, improve airflow around your plants, avoid excess watering of the leaves focusing mainly on the roots of the plant, and treat with applications of Fungus Gun Systemic Disease Spray, ensuring you closely follow the instructions on the label. Regular pruning and removing infected leaves can also help keep it under control.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob