The Facts on Preharvest Fruit Drop

Tacy CalliesProduction, Research

By Tripti Vashisth, Lisa Tang and Sukhdeep Singh In citrus, huanglongbing (HLB) causes an increase in the mature fruit drop rate up to three months prior to commercial harvest. This preharvest fruit drop results in a great reduction in yield and overall grove productivity. Since the plant growth regulators that improve fruit retention on healthy trees do not have consistent …

Thermotherapy’s Effects on Fruit Drop, Yield and Quality

Tacy CalliesThermotherapy

By Megan Dewdney, Evan Johnson, Naweena Thapa and Michelle Danyluk In 2015, we started a large-scale project to determine if thermotherapy would be an effective huanglongbing (HLB) treatment for field trees. Some of the objectives were to determine effective temperature-time combinations for thermotherapy, which season gave optimal results for thermotherapy, and the effect on yield in subsequent years. TRIAL DETAILSComprehensive …

Fruit Drop and HLB

Tacy CalliesHLB Management

By Tripti Vashisth and Lisa Tang Fruit drop is a natural, physiological phenomenon that occurs in all citrus varieties. However, pre-harvest fruit drop often causes grower distress and concern as it can result in significant yield reduction as well as loss of tree resources into non-harvested fruit. THREE PERIODS OF FRUIT DROP In general, citrus trees bloom profusely in spring, …

How to Handle Glyphosate-Related Fruit Drop

Tacy Calliesweeds

By Ramdas Kanissery, Fernando Alferez and Ozgur Batuman Herbicides are one of the key inputs necessary for effective management of a wide diversity of weed infestations in citrus crop production. Most weeds in citrus could be controlled by adopting a weed management program that utilizes a combination of herbicides based on their selectivity and compatibility with the crop. This would …

HLB Management, PGRs and Fruit Drop

Tacy CalliesNews from our Sponsor

Column sponsored by the Citrus Research and Development Foundation Plant growth regulators (PGRs) are chemicals that increase or decrease plant growth, flowering and/or fruit set. PGRs include some herbicides. This article summarizes research studies on how PGRs might aid in the management of HLB. Although several successful herbicide practices were developed by University of Florida Institute of Food and Agricultural …

Outlook for Postbloom Fruit Drop

Tacy CalliesDiseases

By Megan M. Dewdney, Tripti Vashisth and Ariel Singerman In 2017, the damage from postbloom fruit drop (PFD) was lower than the previous three years. This was mainly due to the low rainfall accumulation in late winter and early spring. The long bloom with relatively few flowers at any one time made the decision of when to apply a fungicide …

Will You Be Ready for Postbloom Fruit Drop?

Tacy CalliesDiseases, PFD

By Megan M. Dewdney Again in 2016, postbloom fruit drop (PFD) caused widespread problems in Florida groves. There were multiple factors that contributed to the outbreak in 2016. The primary factor was likely the extended bloom that many saw because of a combination of tree stress caused by huanglongbing (HLB) and the very warm winter. Bloom in some groves was …

PFD

Brazilian Discusses Postbloom Fruit Drop

Ernie NeffPFD

Geraldo Silva, a scientist with Fundecitrus in Brazil, shared thoughts about postbloom fruit drop (PFD) and its control at a recent seminar in Arcadia. Silva says Brazilians assume that the PFD inoculum is present in groves at all times, because consecutive days of rain can bring on a PFD outbreak 10 years after a previous outbreak. “We can have a …

HLB

Postbloom Fruit Drop: It’s All About Timing

Ernie NeffPFD

Postbloom fruit drop (PFD) in recent years has caused many Florida citrus growers as much, or almost as much, anguish as HLB. The Citrus Research and Development Foundation (CRDF) in December approved an extension of PFD research begun in 2016. CRDF Chief Operations Officer Harold Browning discusses PFD and the research. “Progressively the last several years, PFD has increased in …

PFD control

Postbloom Fruit Drop Control: Timing Is Key

Ernie NeffCitrus Expo, Citrus Greening, PFD

Timing of fungicide sprays is the key to controlling the postbloom fruit drop (PFD) that caused many Florida citrus growers severe problems this year. That was a central message that University of Florida researcher Natalia Peres delivered at Citrus Expo this summer. In this interview, Peres discusses the keys to proper spray timing, starting with bloom. Peres says longer bloom …

dorian

Post-Hurricane: Some Fruit Drop on River; Interior Mostly OK

Ernie NeffGrapefruit, Weather

Heavy winds from Hurricane Matthew Friday caused some fruit drop in the Indian River citrus area. But the amount of drop was “not catastrophic,” said Florida Citrus Mutual spokesman Andrew Meadows. “The fact that it stayed offshore helped tremendously,” Meadows said. Some Indian River growers and packers told Mutual that in addition to fruit drop, there will likely be some …

Post-Bloom Fruit Drop Survey

Tacy CalliesPests

A Citrus Research and Development Foundation (CRDF) Research Management Committee meeting was called on June 29, 2016, to discuss post-bloom fruit drop (PFD) caused by Colletotricum spp. in Florida. In this meeting, it was suggested that there is an opportunity to retrospectively investigate PFD management strategies from 2016 to determine if grower treatment programs led to variable results. A survey …

global

Global Grapefruit and Mandarin Crops to Drop

Daniel CooperCrop Forecast, International

A report from the U.S. Department of Agriculture Foreign Agricultural Service (USDA FAS) projects world grapefruit and tangerine/mandarin crops will decline in 2024–25 from the previous season. GRAPEFRUIT Global grapefruit production for 2024–25 is forecast down slightly to 6.9 million tons as decreases in Türkiye and the United States more than offset higher production in China. Exports and fruit for …

greening

Brazil’s Orange Forecast: Less Fruit, More Drop

Tacy CalliesForecast

The 2020–21 orange crop forecast for the São Paulo and West-Southwest Minas Gerais citrus belt in Brazil is 269.36 million boxes. The updated forecast was published Dec. 10 by Fundecitrus and its cooperators. The decrease of 17.36 million boxes represents a 6 percent decline in crop size from the September forecast update. ADVERSE WEATHER CONDITIONSExpected production was significantly hindered by …

Gibberellic Acid: Increase Fruit Size and Yield, Reduce Drop

Tacy CalliesProduction

By Tripti Vashisth and Megan Dewdney This article discusses the use of gibberellic acid (GA), the naturally occurring plant hormone, on huanglongbing (HLB)-affected trees. The results were generated from a 3-year trial in which Valencia trees were treated with GA in the fall. The outcomes suggest that GA can be effectively used for synchronizing and suppressing profuse flowering without negatively …

Grapefruit production costs

Grapefruit Production Costs Drop; Profitability Is Elusive

Ernie NeffBactericides, Economics, Grapefruit

A decrease in grapefruit production costs among Indian River growers allowed the average grower to approach the break-even point in the 2015-16 season, a University of Florida economist reports. Ariel Singerman made his report at the recent Florida Citrus Show in Fort Pierce. The report was based on a July 2016 survey of 70 growers representing a majority of grapefruit …

preharvest

Top Fungal Threats Behind Preharvest Fruit Rot

Daniel CooperDiseases, Research

A new study has identified several fungal pathogens associated with preharvest sweet orange fruit spoilage. It provides insights that could help citrus growers better understand and manage fruit rot problems in the grove. The research, “Morphological Identification of Fungi Associated with Preharvest Spoilage of Sweet Orange (Citrus sinensis L.) Fruit in Bilo Nopha, Southwestern Ethiopia,” was published in the journal …

global lemon

Drop in Global Lemon Supply

Daniel CooperInternational, lemons

A recent review of the 2025–26 global lemon market reported a drop in supply, highlighted by Türkiye’s production collapse. Economists Pablo Resco Sánchez and Pablo Santiago Izu Pérez of Platform Land conducted the review. According to the review, the U.S. Department of Agriculture forecast for the 2025–26 season put global lemon production at around 10.1 million tons. That’s a 6.6% …

leaf

Leaf Quantity Matters for Fruit Quality

Daniel CooperProduction, Tip of the Week

By Tripti Vashisth, Taylor Livingston, Meryam Manzoor and Johann Hiller Citrus fruit quality and yield remain major concerns for sweet orange growers in the huanglongbing (HLB) era. These outcomes largely depend on the tree’s ability to support developing fruit throughout the growing season. Leaf area and canopy density are positively correlated with carbohydrate production and allocation to fruit, directly influencing …

June drop

June Drop Underway in Cold-Hardy Citrus Region

Daniel CooperCold Hardy, Production

It may not be June, but growers in the cold-hardy citrus region are experiencing June drop, a natural thinning process in which trees lose a lot of their fruit. Growers should not be alarmed about excess pieces of fruit that may be on the ground, says Mary Sutton, University of Georgia (UGA) assistant professor and citrus Extension specialist. “We are …