Regulating Valencia orange crops with CEPA (2-chloroethyl phosphonic acid) - preliminary studies

Abstract

The effects of chemicals on fruitlet thinning of Valencia oranges were studied in two experiments at Loxton, South Australia. In the first experiment 50 p.p.m. 245T, 2000 p.p.m. N.A.A. and 250 or 1000 p.p.m. CEPA all caused significant thinning but 245T had phytotoxic effects. In the second experiment with several concentrations of CEPA, both 524 and 1048 p.p.m. caused significant leaf and fruitlet drop, whereas 262 p.p.m. caused a significant reduction of 55 per cent in mature fruit yield without any significant leaf fall.