We have grown Zinnias in our garden since 3-4 years, In South India . The initial batches were very healthy and robust ,with stunning flowers.
but since the last 1 year or so I have noticed that the zinnias seem to have stunted growth and start flowering small flowers before even reaching a height 1 feet even though we provide enough manure.
And these spots appear only after the plants have grown for 1 month or so. Saplings are perfectly spotless. Never seen any grasshopper or other insects chewing on the leaves. But there are tiny red ants swarming on the unopened buds, I suspect they eat the buds. Tried Gammaxene and copious amounts of turmeric powder to drive them away.
There are these black spots with white rings around them ,on the leaves and flowers.
Black spots on the stem.
What are these spots? Are they some fungus? Are there any methods to get rid of them?
Eco friendly methods are appreciated.