Q.Hibiscus curly leaves & buds
My hibiscus plants have leaves which are curling up tightly. Is this a mite or grub and if so how do I get rid of it?

I would, first, look to a pH issue, and after that, a fungal issue. You can correct both of these at the same time by applying dolomitic lime, and wettable sulfur to the area. This should take care of the problem. The old growth will not recover, but the new growth should come out looking normal. Here is an article for hibiscus care: https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/how-to-care-for-hibiscus-plants.htm