Need help with our hibiscus plants. It seems there it is attacked by some kind of disease which seem to be impacting all the new spring shoots. I have uploaded the image of the impacted area of plant.
Any suggestion as to what needs to be done to get rid of it.
Thank you for your assistance.
I am based in Sydney and been watering the plant regularly.
With regards to care, been spraying with white oil and been adding soil improver around the tree.
This looks suspiciously like Hibiscus Black Spot which is a fungal disease, not unlike the black spot that affects roses. Some insects are also capable of causing black spotting, but in my opinion this is fungal rather than insect.
eco-fungicide should take care of it. Follow the instructions for making it up and application. You may need to repeat spray to gain the upper hand.
The other thing to watch is to try and keep the leaves dry as fungal diseases can be spread in water droplets. I see you have drippers installed, which is great for watering these plants, but that doesn't stop rain drops spreading disease from one leaf to another.
Thanks you for the suggestion. Let me give it a try and see if it makes a difference.