Low-Volume Sprayer Rodeos

Low-Volume Sprayer Rodeos

In September, two citrus sprayer calibration clinics, also called rodeos, were organized by the Florida Extension Service, in conjunction with several grower association in Lake Placid and Haines City. Growers and applicators in the region were invited to bring their low-volume equipment to these locations to obtain droplet size measurements for the control of Asian citrus psyllid.

These rodeos were conducted to evaluate the spray performance of existing pesticide-application systems and to make any necessary adjustments to the spray equipment based on that information to ensure label compliance. However, the number of insecticides that are actually approved for low-volume application to control psyllids is limited. As a result of the urgent need for psyllid control, applicators in Florida have been granted Special Local Need (SLN) provisions on a number of insecticides including Delegate WG (spinetoram, Dow AgroSciences) and Micromite 80WGS (diflubenzuron, Chemtura Corp). Both of these SLN labels require air-blast or air-assisted sprayers with application rates of no less than 2 gallons per acre and with volume median droplet diameters of 90 microns (µm) or larger. Given that spray-droplet size is dependent on the type of spray equipment, equipment setup, and spray product, the objective of these rodeos was to evaluate the droplet size produced by low-volume sprayers used in citrus greening control programs, and where appropriate, adjust the sprayers to produce a volume median diameter of 90 µm or greater.

Testing Technique

Each of the sprayers was loaded with a water and surfactant solution and operated with the same equipment settings that the applicator had been using in the groves. The droplets from the sprayer were measured once they left the sprayer through the use of a laser-diffraction instrument. As the spray droplets pass through the laser, the laser is bent or diffracted more or less based on the size of the droplet. The amount or degree that the laser beam is bent is detected by the measurement system and is used to calculate the droplet’s size. During a spray test, the laser is traversed through the entire spray plume from a nozzle or sprayer so that the whole plume is sampled. In a typical test, tens of thousands of droplets are measured and reported by the measurement system.

Rodeo Results

In response to the need for accurate droplet size assessments of application equipment used in the control of the Asian citrus psyllid in Florida, 33 machines were evaluated representing 16 different models of sprayers. The most common sprayers at the rodeos were Curtis Dyna-Fog LV-8s and London Fog 1820s.

From these tests, it was found that for the air-blast type sprayers, reductions in engine speed from full throttle (~2,600 rpm) to around 2,000 rpm were required to increase droplets to the required size. For air-assisted sprayers, increased flow rates generally increased droplet size. All of the sprayers in the rodeos, with one exception, which was designed to generate droplets in the 30-40 µm range, were adjusted via the engine speed or spray rate such that the resulting spray’s volume median diameter was greater than or equal to 90 µm. As the spray equipment tested represents the most typical application equipment used in Florida for psyllid control, these results will provide applicators, growers, and Extension agents with general guidelines to insure spray systems are operated in a manner that complies with label restrictions.

Leave a Reply

Citrus 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
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
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
Packinghouse 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
Biocontrols Conference
September 11, 2017
The Grower’s Take: Citrus, HLB, and Biological Control
Uncle Matt’s Organic orange juice brand has enjoyed steady growth since its 2002 inception. The brand’s success is due to Read More
Citrus
September 7, 2017
Summer News Stories that Have Growers Talking
Farming has been in the media spotlight this year. I asked each of this month’s columnists and contributors for their Read More
Citrus
September 7, 2017
Whose Sustainable Standard Wins?
Retailers’ race to win the most sustainable produce prize leaves growers trying to keep up with fast-developing demands. Read More
Citrus
September 7, 2017
Improving Water Management: Can Silicon Valley Help?
Though very much-needed, technological solutions must be cost-effective and industry appropriate. Read More
Florida oranges
Citrus
August 31, 2017
Extra Early Florida Citrus Forecast Calling For Sunshine
Marked increase in production predicted for the next crop of oranges. Read More
Citrus
August 30, 2017
How Harvey May Impact Specialty Crop Growers
The devastating human toll from Hurricane/Tropical Storm Harvey has rightly dominated news coverage. Growers and those who work with them, however, should also think about how this historic storm will also affect them.  Read More
Insect & Disease Update
August 28, 2017
California Extends Citrus Quarantine
A 94-square mile area of San Bernardino, Riverside counties now a part of state huanglongbing quarantine. Read More
Strawberry fieldworker in Florida
Citrus
August 28, 2017
Specialty Crop Concern Feeds Need to Negotiate NAFTA Now
Although trade talk objectives may not deliver the short-term relief for Florida fruit and vegetable growers, they appear on the right track. Read More
Cannabis plant closeup
Citrus
August 28, 2017
3 More Florida Growers Given Green Light to Cultivate Medicinal Cannabis
Once exclusive enterprise continues to expand for more seeking to engage alternative crop endeavor. Read More
multiple hands holding a plate full of veggies
Citrus
August 27, 2017
USDA Releases Software to Help Small Operations with Food Safety Plans
While the free tool was primarily designed for use by small firms, any size manufacturer can opt to use it. Read More
The Latest
Citrus
September 22, 2017
When it Comes to Growing, Florida Farmer…
Let's raise a toast to the bold producers and researchers who are taking our industry beyond previously perceived crop viability boundaries to places once figured forbidden. Read More
Citrus
September 21, 2017
Hurricane Relief Fund Launched for Flori…
Money raised will benefit Redlands Christian Migrant Association’s efforts to aid families in need. Read More
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
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
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
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
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
Citrus
September 7, 2017
Summer News Stories that Have Growers Ta…
Farming has been in the media spotlight this year. I asked each of this month’s columnists and contributors for their Read More
Citrus
September 7, 2017
Whose Sustainable Standard Wins?
Retailers’ race to win the most sustainable produce prize leaves growers trying to keep up with fast-developing demands. Read More
Citrus
September 7, 2017
Improving Water Management: Can Silicon …
Though very much-needed, technological solutions must be cost-effective and industry appropriate. Read More
Citrus
August 31, 2017
Extra Early Florida Citrus Forecast Call…
Marked increase in production predicted for the next crop of oranges. Read More
Citrus
August 30, 2017
How Harvey May Impact Specialty Crop Gro…
The devastating human toll from Hurricane/Tropical Storm Harvey has rightly dominated news coverage. Growers and those who work with them, however, should also think about how this historic storm will also affect them.  Read More
Citrus
August 28, 2017
Specialty Crop Concern Feeds Need to Neg…
Although trade talk objectives may not deliver the short-term relief for Florida fruit and vegetable growers, they appear on the right track. Read More
Citrus
August 28, 2017
3 More Florida Growers Given Green Light…
Once exclusive enterprise continues to expand for more seeking to engage alternative crop endeavor. Read More
Citrus
August 27, 2017
USDA Releases Software to Help Small Ope…
While the free tool was primarily designed for use by small firms, any size manufacturer can opt to use it. Read More
Citrus
August 25, 2017
Transcending Farm Labor Crisis No Easy T…
Technology could be on cusp of fixing labor problems for growers of crops that are traditionally hand harvested. Read More
Citrus
August 25, 2017
California EPA Seeking to Review Chlorpy…
Department of Pesticide Regulation, Office of Environmental Health pursuing health protections. Read More