Never use malathion on hibiscus. Strong dry winds can burn leaves but they will recover. For heavy infestations, use a combination of the chemical Orthene and liquid soap. Ants farm aphids for a honey-like secretion they produce. No aphids, no ants.
Most spider mites are too tiny to be seen without the aid of a magnifying glass.
Their webs may or may not be noticeable. Miticides or fine horticultural oils applied four times break the life cycle. Treat these sucking insects in spring when they are young and moving. Causes can be too much water or not enough water, too much fertilizer or not enough, or insect damage. Check for insects and reverse whatever else you are doing or not doing.