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https://www.gardeningknowhow.com/edible/vegetables/vgen/vegetable-garden-pests.htm

There is no easy answer, blight is not just one pathogen, but there are specific disease organisms and insect pests that attack different host plants, so there is no one cure to fit all.
Plant health and resistance to pests and diseases can be addressed in a general way by improving soil fertility and with good water management.
Specific plant problems need to be identified and managed with specific bio-pesticides. The one general purpose insecticide, miticide and fungicide is 70% neem oil as a foliar spray. This is organic program compatible because it biodegrades and is not persistent in the environment. But to be effective, it has to be sprayed every two weeks for preventive treatment. Active, advanced infections are hard to control and reversal of damage is usually not possible. Prevention of spread and of new infections is what you can shoot for.

The leaves could be picked up by animals or even humans and could be toxic to them.

https://www.gardeningknowhow.com/plant-problems/pests/insects/how-to-control-ants-in-lawns.htm

This is a mild fertilizer, and will benefit anything that you use it on. I would say go ahead! There will be no harm in doing so.

This article will help you.

https://www.gardeningknowhow.com/plant-problems/pests/insects/fire-ant-control.htm

Make sure to add some dolomitic lime, as the pH may be off. Also, just in case there is some sort of infection, you should add some wettable sulfur to the area, and work it in. This will help re-mediate your soil.