Popular Mechanics

During the 2008-2009 season, 35,600 acres producing 9½ million boxes were mechanically harvested. The economic potential remains strong for existing harvesting equipment to dramatically reduce harvest costs and increase on-tree returns. Several impediments, however, still need to be overcome before the full benefits of mechanical harvesting can be realized. Incorporating fruit loosening abscission chemicals into the harvesting systems, addressing grower concerns about tree health, eliminating gleaning of unharvested fruit, and minimizing harvest debris in trailer loads are four challenges. These issues are being addressed by the collective efforts of Florida growers, harvesters, juice processors, and researchers. Solving these challenges would increase the adoption of mechanical harvesting, greatly enhance the harvesting capacity of existing equipment, and lower overall harvesting costs.

Abscission Obsession

Harvesting late season Valencia is the biggest barrier of current mechanical systems. Once next season’s bloom fruitlets grow to more than 1 inch in diameter, they are readily removed by mechanical harvesting equipment and might cause a reduction in the next season’s yield by at least 25%. Abscission compounds, specifically CMNP (5-chloro-3-methyl-4-nitro-1H-pyrazole), should solve this problem as it loosens fruit and allows equipment to operate with less shaking force. Current research efforts are collecting data that focus on CMNP concentration, harvester settings, and harvest timing. Data from this work is being used to develop a predictive model to ensure CMNP will be applied with the maximum probability of success. Presently, research trials on CMNP are limited to 10 treated acres annually, and all treated fruit must be destroyed.

If EPA grants an experimental use permit (EUP) for CMNP, the number of treated acres should be greatly expanded and treated fruit would be processed for juice. The additional data collected under the EUP will refine the predictive model.

Tree Health

The duration, speed, and intensity of the shaking action during mechanical harvesting can cause leaf loss and visible scarring of tree limbs and trunks. Growers have long been concerned that such damage might lead to reduced tree health and yields and ultimately increased tree mortality. UF/IFAS research trials have repeatedly shown healthy, well-nourished trees suffer no negative effects from mechanically harvesting. Specific studies have examined the effects of leaf loss, root damage, and drought stress in conjunction with mechanical harvesting. Results of these studies confirm citrus trees have the capacity to adapt to a number of stress factors as long as a tree’s nutrition and irrigation requirements are well managed. Application of an abscission agent (CMNP) should ease growers’ lingering tree health concerns in that machines could harvest fruit with less force, and thus reduce visible tree damage.

Gleaning And Machine Design

Harvesting contractors are reporting 75% to 82% fruit recovery with existing catch-frame designs. This means that, in an average block, between 80 and 120 boxes per acre are being gleaned by hand crews at an average cost of $3 per box (pick and roadside). Improved catch-frame design and better synchronization between harvesting units should enhance fruit recovery of a self-propelled canopy shaker and reduce the number of boxes gleaned. Addition of an abscission agent compound (CMNP) should facilitate fruit removal and increase overall fruit recovery.

An important goal is to improve fruit recovery to a point where gleaning becomes uneconomical. An analysis of productivity data indicates when gleaners have access to less than 20 boxes per acre, their productivity falls to less than 3 boxes per hour. If they expect to earn $9 per hour, their piece rate to glean fruit has to be increased to at least $3 per box. With the additional costs of roadside and fruit hauling, gleaning would only be profitable under extremely favorable market conditions.

Harvest Debris

Mechanical harvesting, without an abscission agent, has been shown to increase the amount of harvesting debris loaded into trailers and transported to processing plants. Juice processors are concerned woody debris can damage processing equipment, cause downtime in plant operations, and diminish overall juice-yield recovery. Although some of this debris removal might actually be good for the trees, an application of an abscission agent, along with mechanical harvesters, has been shown to reduce harvesting debris to equivalent levels of hand-harvested loads. Self-propelled canopy shakers need to fill at least 20 trailers a day to operate efficiently. Juice processors who control the daily load allocations to harvesting sites around the state have little economic incentive to accommodate these systems if their operating costs increase due to excess harvest debris.

A survey is under way to estimate the cost of handling debris at a juice-processing plant. The results of this survey should help focus an industry discussion on what would be the most cost-effective way to handle or avoid harvest debris. Faculty at UF/IFAS are working with the Florida Department of Citrus’ Harvest Research Advisory Council, the Southwest Florida Mechanical Harvesting Advisory Committee, and AgroSource, the private company contracted by the DOC to submit the CMNP registration package to EPA and to commercialize CMNP once it is approved by the EPA. To learn more, visit
http://citrusmh.ifas.ufl.edu.

Leave a Reply

2 comments on “Popular Mechanics

Featured Stories
Citrus
September 19, 2017
Precision in Specialty Crops Gains Momentum
Here are some of the key drivers that may transform your farm in the years ahead. Read More
Fruits
September 19, 2017
EPA Mulls Restricting Dicamba Use
Proposal is a part of agency’s focus on reducing herbicide injury in vulnerable crops. Read More
Fruits
September 19, 2017
Washington State University Creates BMSB Management Resource Page
As populations grow in the state, university offers growers pest management advice. Read More
Berries
September 19, 2017
UC Davis Strawberry Lawuit Settled
Former university breeders to return any crosses that used unpatented varieties and agree the school owns rights to them. Read More
Neo 1 hops at UF/IFAS MREC
Citrus
September 19, 2017
Hopes High for Hops Fresh From Florida
When it comes to alternative crop solutions, something good is brewing in the Sunshine State. Do you have what it takes to tap in? Read More
Apples & Pears
September 16, 2017
Researcher Finds Bacteria Can Stop Blue Mold on Apples
The natural bacterium found in soil can survive in cold storage; this promising biocontrol offers an alternative to chemical treatments. Read More
Laurel wilt-damaged avocado tree leaves
Disease Control
September 15, 2017
Scientist Uncovers Chilling Side of Deadly Avocado Disease
Lab tests indicate laurel wilt pathogen grows faster in the fall and winter. Read More
Winter melon damage from Hurricane Irma in Elkton, FL
Citrus
September 15, 2017
Help Extended to Hurricane-Weary Farmers Dealing With Disaster
USDA chief grants extra time and special procedures to document and file claims. Read More
raindrops in standing water
Citrus
September 13, 2017
New Guidance on FSMA Ag Water Compliance, Water Testing, and Farm Inspections Announced
FDA issued a rule to extend compliance dates for agricultural water and announced a start date for farm inspections. Read More
Biocontrols Conference
September 13, 2017
Get Better Results From Your Biopesticide Program
Softer crop protection programs are becoming a must in specialty crop production. Growers who aren’t learning more about their options Read More
citrus grove damage from Irma at SWFREC in Immokalee
Citrus
September 13, 2017
Florida Farmers Digging out From Impacts of Irma
Damage reports starting to flood in from the field following monster storm, and it's not pretty. Read More
Tomatoes
September 13, 2017
550 Pounds of Tomatoes Stolen from Massachusetts Farm
Community farm in Waltham, MA, has been hit by a thief three years running. Read More
Berries
September 12, 2017
Longtime American Fruit Grower Columnist Charlie O’Dell Dies
“The Ole Crow,” as he called himself, passed away unexpectedly at home in Virginia at the age of 82. Read More
Berries
September 12, 2017
How to Match Drip Irrigation to Improve Berry Water Management
Using root mass diameter to appropriately determine wetting pattern will help you improve growth rate and yields. Read More
Grapes
September 12, 2017
Heat Wave Leads to Early Winegrape Harvest in California’s Sonoma County
Ask any winegrape grower to describe the grape harvest in Sonoma County and you typically hear “harvest time is like Read More
The Latest
Citrus
September 19, 2017
Precision in Specialty Crops Gains Momen…
Here are some of the key drivers that may transform your farm in the years ahead. Read More
Fruits
September 19, 2017
EPA Mulls Restricting Dicamba Use
Proposal is a part of agency’s focus on reducing herbicide injury in vulnerable crops. Read More
Fruits
September 19, 2017
Washington State University Creates BMSB…
As populations grow in the state, university offers growers pest management advice. Read More
Berries
September 19, 2017
UC Davis Strawberry Lawuit Settled
Former university breeders to return any crosses that used unpatented varieties and agree the school owns rights to them. Read More
Citrus
September 19, 2017
Hopes High for Hops Fresh From Florida
When it comes to alternative crop solutions, something good is brewing in the Sunshine State. Do you have what it takes to tap in? Read More
Apples & Pears
September 16, 2017
Researcher Finds Bacteria Can Stop Blue …
The natural bacterium found in soil can survive in cold storage; this promising biocontrol offers an alternative to chemical treatments. Read More
Disease Control
September 15, 2017
Scientist Uncovers Chilling Side of Dead…
Lab tests indicate laurel wilt pathogen grows faster in the fall and winter. Read More
Citrus
September 15, 2017
Help Extended to Hurricane-Weary Farmers…
USDA chief grants extra time and special procedures to document and file claims. Read More
Citrus
September 13, 2017
New Guidance on FSMA Ag Water Compliance…
FDA issued a rule to extend compliance dates for agricultural water and announced a start date for farm inspections. Read More
Biocontrols Conference
September 13, 2017
Get Better Results From Your Biopesticid…
Softer crop protection programs are becoming a must in specialty crop production. Growers who aren’t learning more about their options Read More
Citrus
September 13, 2017
Florida Farmers Digging out From Impacts…
Damage reports starting to flood in from the field following monster storm, and it's not pretty. Read More
Tomatoes
September 13, 2017
550 Pounds of Tomatoes Stolen from Massa…
Community farm in Waltham, MA, has been hit by a thief three years running. Read More
Berries
September 12, 2017
Longtime American Fruit Grower Columnist…
“The Ole Crow,” as he called himself, passed away unexpectedly at home in Virginia at the age of 82. Read More
Berries
September 12, 2017
How to Match Drip Irrigation to Improve …
Using root mass diameter to appropriately determine wetting pattern will help you improve growth rate and yields. Read More
Grapes
September 12, 2017
Heat Wave Leads to Early Winegrape Harve…
Ask any winegrape grower to describe the grape harvest in Sonoma County and you typically hear “harvest time is like Read More
Nuts
September 12, 2017
Walnut Crop Expected to be Down 5%
While wet California winter was welcome to growers, some orchards were flooded, compromising root systems. Read More
Biocontrols Conference
September 11, 2017
The Grower’s Take: Citrus, HLB, and Biol…
Uncle Matt’s Organic orange juice brand has enjoyed steady growth since its 2002 inception. The brand’s success is due to Read More
Farm Management
September 10, 2017
$3 Million Available to Train Future Agr…
There are a lot more jobs being created than there are graduates with bachelor’s or higher degrees who can fill them. Read More