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

GrapesNorthern Grapes Project Receives $2.6 Million USDA Grant
October 24, 2014
Funds will help complete final two years of multistate effort. Read More
VegetablesEnza Zaden Field Day Highlights 25 Vegetable Varieties [Slideshow]
October 24, 2014
Seed breeder Enza Zaden hosted its 2014 variety showcase September 25th at the company’s research station in San Juan Bautista, California, with 250 Read More
Disease ControlWashington Concord Grape Growers Wrestle With Blackleaf
October 23, 2014
Physiological disorder manifested due to unusually hot and sunny summer. Read More
More Vegetables7 Green Bean Varieties Geared For Florida Growers
October 23, 2014
Leading vegetable seed companies highlight several high-performance selections for producers in the Sunshine State. Read More
MarketingTomato Survey Tracks Consumer Trends
October 23, 2014
Results indicate how labeling matters in purchasing decisions. Read More
CitrusFlorida Citrus Growers Get Box Tax Relief
October 23, 2014
Citrus Commission votes to put dollars back in producers’ hands to spur reinvestment. Read More
Farm ManagementBill Gates Uploading Lots Of Florida Farmland
October 22, 2014
Recent acquisition for the Microsoft icon involves more than 4,500 acres for nearly $28 million. Read More
GenNext GrowersRegister Now For The GenNext Growers Webcast
October 22, 2014
In the first installment of the GenNext Webcast Series, you will learn how to engage with lawmakers and ag associations to help shape a better future for your business and for agriculture. Read More
FruitsAnnual Santa Maria Strawberry Meeting Approaching
October 22, 2014
The meeting will focus on IPM practices, weed management, updates on fumigation, and more. Read More
Apples & PearsUSApple’s AppletizeMe Personality Quiz Help Consumers Find Ideal Apple Varieties and Perfect Food Pairings
October 22, 2014
Award-winning national apple month campaign returns with more featured varieties and informative videos. Read More

The Latest

GrapesNorthern Grapes Project Receives $2.6 Million USDA Gran…
October 24, 2014
Funds will help complete final two years of multistate effort. Read More
VegetablesEnza Zaden Field Day Highlights 25 Vegetable Varieties …
October 24, 2014
Seed breeder Enza Zaden hosted its 2014 variety showcase September 25th at the company’s research station in San Juan Bautista, California, with 250 Read More
Disease ControlWashington Concord Grape Growers Wrestle With Blackleaf
October 23, 2014
Physiological disorder manifested due to unusually hot and sunny summer. Read More
More Vegetables7 Green Bean Varieties Geared For Florida Growers
October 23, 2014
Leading vegetable seed companies highlight several high-performance selections for producers in the Sunshine State. Read More
MarketingTomato Survey Tracks Consumer Trends
October 23, 2014
Results indicate how labeling matters in purchasing decisions. Read More
CitrusFlorida Citrus Growers Get Box Tax Relief
October 23, 2014
Citrus Commission votes to put dollars back in producers’ hands to spur reinvestment. Read More
Farm ManagementBill Gates Uploading Lots Of Florida Farmland
October 22, 2014
Recent acquisition for the Microsoft icon involves more than 4,500 acres for nearly $28 million. Read More
GenNext GrowersRegister Now For The GenNext Growers Webcast
October 22, 2014
In the first installment of the GenNext Webcast Series, you will learn how to engage with lawmakers and ag associations to help shape a better future for your business and for agriculture. Read More
FruitsAnnual Santa Maria Strawberry Meeting Approaching
October 22, 2014
The meeting will focus on IPM practices, weed management, updates on fumigation, and more. Read More
Apples & PearsUSApple’s AppletizeMe Personality Quiz Help Consumers…
October 22, 2014
Award-winning national apple month campaign returns with more featured varieties and informative videos. Read More
Farm ManagementUSDA Awards $18 Million To Stimulate Research And Devel…
October 22, 2014
The grants will provide resources to help small operations create breakthroughs, says USDA Secretary Tom Vilsack. Read More
CitrusEPA Launches Program To Reduce Pesticide Drift
October 22, 2014
The voluntary star-rating program aims to protect people, wildlife and the environment. Read More
CitrusMcCrometer Introduces New Ag Management Mobile App
October 22, 2014
The app displays data on weather, ET, soil moisture, water flow, and more. Read More
Apples & PearsNew York Apple Growers Partner With Grocer To Introduce…
October 22, 2014
First apples of this new variety to hit Wegmans stores as part of a marketing effort. Read More
CitrusAgriculture, Interior Departments Partner To Measure Co…
October 22, 2014
Goal is to provide science-based information for watershed wellness. Read More
Stone FruitIntroducing A Gem Of A Peach For Central Florida
October 22, 2014
The newest variety to come from the UF Stone Fruit Breeding Program is another “gem,” UFGem! This peach variety is Read More
CitrusIt’s Time For Young Farming Leaders To Engage [Op…
October 21, 2014
Florida Grower editor Frank Giles says there are capable and talented youths in the ag field ready to step up and take the reins. Read More
Farm ManagementResearchers Finding Biofuel Fits For Florida
October 21, 2014
Alternative crops identified that are suited for the state's climate and can easily be processed for power. Read More