Optimize Zinc and Potassium Applications to Prevent Fruit Drop

Josh McGillFruit Drop, Nutrition, Tip of the Week

By Fernando Alferez, Daniel Boakye, Murillo De Sousa and Pablo Orozco After HLB was first detected in Florida, increase in disease-associated preharvest fruit drop in affected trees has significantly reduced grower returns. Fruit drop is normal in healthy citrus, accounting for 10% to 15% of the total crop. However, under endemic HLB conditions and depending on the variety, crop loss …

Prepare for the Possibility of Postbloom Fruit Drop 

Josh McGillDiseases, Tip of the Week

By Megan M. Dewdney Postbloom fruit drop (PFD) is a sporadic flower disease. It is primarily caused by the fungus Colletotrichum acutatum. While infections only occur on flowers, the fungus is present on trees throughout the year. It survives by producing resting structures on leaves and stems. How the inoculum survives multiple years between infections is still unclear. The fungus …

Alico: Fruit Drop Significant; Most Trees Intact

Josh McGillhurricane

Alico, Inc. reported on Sept. 30 that initial observations following Hurricane Ian indicate there was significant drop of fruit in its groves. However, most trees remain intact. The magnitude of the fruit drop will be formally calculated by the company’s staff and insurance companies in coming weeks. Alico has 48,900 acres of citrus groves in Charlotte, Collier, DeSoto, Hardee, Hendry, …

Impact of Herbicides on Fruit Drop

Josh McGillAll In For Citrus Podcast, Fruit Drop, Herbicides

Growers know the negative impacts of any kind stress on trees infected by HLB. That raised a question: Can injury from herbicides make fruit drop worse? Ramdas Kanissery, an assistant professor of weed science with the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS), conducted a research project to help answer that question. Kanissery discusses the research in …

Fruit Flies Are Major Cause of Fruit Drop in Brazil

Josh McGillBrazil, Fruit Drop, Pests

Brazil’s Fundecitrus recently pointed out that fruit flies, along with citrus fruit borers, are primarily responsible for the country’s citrus fruit drop. The organization suggested that monitoring and management must be taken to avoid economic damage, since fruit flies occur throughout the year. Fundecitrus described the fruit flies that cause damage in Brazil and suggested control measures.   Two species of …

Herbicides and Fruit Drop

Josh McGillFruit Drop, Research, weeds

Weed scientist Ramdas Kanissery’s research has not shown evidence that herbicides, including glyphosate, increase citrus fruit drop or decrease yields. But in studies using different glyphosate rates, he did find that there is a relatively strong negative correlation with the fruit detachment force and the glyphosate amount applied. “That means there may be something happening with the higher glyphosate rate” …

Webinar to Address PGRs and Fruit Drop

Josh McGillFruit Drop

Florida citrus growers can learn more about the use of plant growth regulators (PGRs) in the fight against fruit drop at an upcoming online seminar. The webinar will be at 10 a.m., April 27 and will be presented by the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS). Speakers at the webinar, titled “Gibberellic Acid Research Update and …

Be Prepared for Postbloom Fruit Drop

Josh McGillFruit Drop, Research

A La Niña weather pattern is most likely this spring, with higher-than-average temperatures and below-average rain predicted in Florida, researcher Megan Dewdney reported in a Feb. 24 presentation about postbloom fruit drop (PFD). That could have some influence on the severity of PFD, since its preferred climate is humid and subtropical, and the fungus moves with rain splash and wind-borne …

Florida Citrus Growers Seeking Solutions to Fruit Drop

Josh McGillCitrus, Florida, Fruit Drop

Fruit drop has plagued Florida citrus groves in recent years. The problem has been a major factor in tumbling yields. The February 2022 U.S. Department of Agriculture’s citrus crop forecast put Florida’s orange estimate at 43.5 million boxes. If realized, it would represent an 18% decline in the crop from last season. Growers are turning over every stone to seek …

Can Zinc and Potassium Curb Fruit Drop?

Tacy CalliesFruit Drop

The Florida citrus industry has been focused on finding solutions to the fruit drop problem that has hit groves hard in recent years. During the 2022 Florida Citrus Show in Fort Pierce, Fernando Alferez, University of Florida Institute of Food and Agricultural Sciences, assistant professor of citrus horticulture, presented findings from a research trial aimed at reducing fruit drop. The …

Keep an Eye Out for Postbloom Fruit Drop This Spring

Josh McGillFruit Drop, Tip of the Week, Weather

By Megan M. Dewdney Postbloom fruit drop (PFD) is a flower disease mainly caused by the fungus Colletotrichum acutatum. The fungus is present on citrus trees throughout the year but survives by producing resting structures on leaves and stems. The fungus becomes stimulated to produce spores by substances from the early flowers. These early spores infect the initial flowers and …

CRDF Funds Fruit Drop Research, Hears Antibiotic Presentations

Josh McGillDiseases, Research

The Citrus Research and Development Foundation (CRDF) governing board on Jan. 25 approved a project aimed at reducing fruit drop by using potassium, zinc, gibberellic acid and the herbicide 2,4-D in different timing scenarios. The funding will allow University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researcher Fernando Alferez to finish two years of work that CRDF Chief …

Making Sense of Biologicals: An Alternative to Managing Premature Fruit Drop

Tacy CalliesMSOB

One instance of fruit drop is expected and needed every growing season for Florida citrus producers. A second instance, however, is unexpected, unwanted and just what growers do not need right before harvest time. HLB WORSENS DROPBut that is a scenario Florida citrus growers encounter every year. This problem has only worsened in the era of citrus greening disease, also …

Reducing HLB-Associated Preharvest Fruit Drop

Tacy CalliesFruit Drop

By Tripti Vashisth and Christopher Vincent This article summarizes current knowledge about HLB-associated preharvest fruit drop. Unfortunately, exactly how HLB induces preharvest fruit drop is still unknown. Nonetheless, this article links what we do know about HLB-associated fruit drop to fruit drop in HLB-free trees and how strategies, such as managing tree water status and use of gibberellic acid, can …

Steps for Reducing Fruit Drop

Ernie NeffFruit Drop

Editor’s Note: Tripti Vashisth with share new information on the use of gibberellic acid treatments to improve health and yield of HLB-diseased trees in a virtual seminar on Sept. 21. Register here. Researcher Tripti Vashisth told the recent Citrus Expo audience how fruit drop might be reduced through the use of nutrition and irrigation strategies, gibberellic acid and increased fruit …

Fruit Drop Is Biggest Grower Concern

Ernie NeffFruit Drop

Fruit drop “is probably the No. 1 concern” of the citrus growers he knows, says Ray Royce, executive director of Highlands County Citrus Growers Association (HCCGA). “Fruit drop and profitability are going hand in hand,” he adds. “There’s a tremendous struggle now to be profitable, given the relatively low harvest numbers,” Royce says. “I think growers believe that if they …

Understanding Physiological Fruit Drop of Citrus

Tacy CalliesFruit Drop, Tip of the Week

By Tripti Vashisth, Megan Dewdney and Lauren Diepenbrock Citrus flowers profusely, but less than 2% of the flowers become harvestable fruit. In other words, 98% of the flowers seen during bloom will end up on the grove floor at some point during fruit development, whether as a flower, fruitlet, young fruit or mature fruit. Profuse flowering allows trees to produce …

Fruit Drop: When to Harvest

Tacy CalliesFruit Drop

By Ariel Singerman and Stephen H. Futch In the 2020–21 citrus season, fruit drop has severely impacted orange yield in Florida. According to a recent U.S. Department of Agriculture (USDA) citrus crop forecast, the estimate of fruit drop for early/mid-season and Valencia oranges was 43% and 34%, respectively. Moreover, according to some growers, the level of fruit drop has been …

Growers Discuss Fruit Drop and More

Ernie NeffFruit Drop

Fruit drop, drought, fruit quality, production costs, deer and Diaprepes root weevil were among problems that bothered Peace River Valley Citrus Growers Association (PRVCGA) members in the 2020-21 season. Those were the issues raised by panelists at a PRVCGA grower roundtable luncheon on May 4 in Hardee County, Florida.   “The fruit drop has been the biggest problem this year,” …