Methods of fruit thinning fruit bearing plants using photosynthesis inhibiting fruit thinning agents are disclosed. Methods of determining the amount and/or timing of a first dose of photosynthesis inhibiting fruit thinning agents to be applied to a fruit bearing plant to thin fruit on the plant are disclosed. Methods of determining whether a second application of photosynthesis inhibiting fruit thinning agent is required to be applied to thin fruit on the plant, and if so the amount and/or timing thereof, are also disclosed. Methods of determining whether a dose of a photosynthesis inhibiting fruit thinning agent is required to be applied to a fruit bearing plant to thin fruit on the plant.