Ethephon as a fruit thinning agent for ‘Murcott’ mandarins

Ethephon (2-chloroethylphosphonic acid) was tested as a fruit thinning agent in an experiment on the mandarin cultivar ‘Murcott’.Ethephon was effective at 150 and 300 mg l^?1, but 300 mg l^?1 gave the higher yield and larger fruit sizes over a 2-year period, following a single spray application during natural fruit fall in November. The thinning percentage was also higher when ethephon was applied to trees with a heavy crop density than when applied to trees with a light crop density.