Mechanical harvest of paprika pepper (Capsicum annuum L.) produces a mixture of marketable and unmarketable fruit. Our objective was to increase the percentage of marketable red fruit in a once-over harvest by using ethephon to remove late-developing flower buds, blooms, and green fruit. Three experiments were conducted on field-grown plants in southwestern Oklahoma. We tested ethephon solutions of 0, 1000, 2000, 3000, and 4000 μL·L-1 as a one-time foliar application on various dates in September and October. Total dry mass of harvested fruit decreased linearly as ethephon rate increased in all experiments. Marketable fruit, as a percentage of total harvested fruit mass, increased linearly with ethephon rate in two of three experiments. Ethephon decreased the percent of total harvested fruit mass due to green fruit in all experiments. We recommend a single application of ethephon at about 2000 to 3000 μL·L-1 as a controlled abscission agent to increase the percentage of harvested red fruit in paprika pepper. The precise timing of the application will vary with the situation, but the last 10 days in September seemed an appropriate interval for southwestern Oklahoma. Chemical name used: (2-chloroethyl)phosphonic acid (ethephon).
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