A preliminary study of the influence of chemical sprays on fruit set and abscission in Robusta coffee (Coffea canephora) Pierre ex Froehner

Abstract

Application of 200 ppm of gibberellic acid before anthesis produced some reduction in the percentage of fruit retained 28 days after fruit set but had little effect on the actual percentage of fruit set in Robusta coffee (Coffea canephora Pierre ex Froehner). In the same cultivar, 100–1000 ppm of ethrel (2-chloroethyl phosphonic acid) produced large reductions in the percentage of fruit retention in two separate experiments. Concentrations of 500 and 1000 ppm resulted in total fruit loss within four months of application in one experiment. It was concluded that ethrel offered some potential to reduce the number of fruits produced by young coffee plants in their first years of production.