Explore the latest research on a solution for citrus fruit drop from a UF/IFAS citrus horticulturist.

Citrus fruit drop has been an issue in the 2020-2021 citrus season, according to a Citrus Industry article. While 10 to 15 percent drop is normal in any given year, citrus fruit drop has caused up to 50 percent fruit loss in the past. UF/IFAS citrus horticulturist, Fernando Alferez, has been doing research into a solution for citrus fruit drop, and he shared the preliminary findings during a recent UF/IFAS OJ Break webinar. See the details below.

Details on a Solution to Citrus Fruit Drop

“We can modify hormonal balance in the fruit with commercial, feasible treatments applied at the right time. These treatments help to alleviate fruit drop and increase yield,” Alferez said in the article.

Researchers have tied zinc deficiencies to plant stress, inhibited growth, poor fruit, and fruit drop. Alferez’s research included trials where zinc or indole acetic acid treatments were applied to citrus trees, specifically Hamlin on Swingle and US-942 rootstocks, to see if there was an impact on citrus fruit drop.

The results showed that both had seasonal effects on citrus fruit drop, with both trials resulting in less fruit drop with treatments applied in June and October. However, treatments made in August caused an increase in fruit drop. “The timing of application is critical for treatment success. This must be defined for each variety and treatment and depends on the physiological status of the fruit,” Alferez said.

A second year of the zinc trials saw an increase of 25 boxes per acre for Hamlin on Swingle and 19 boxes per acre for Hamlin on US-942, making zinc a promising solution for citrus fruit drop.

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