Question. As an enclosed-cabbed tractor ages, will the seal around the doors 
wear out, or better yet, how do you verify the enclosed cab is providing the 
protection you are after?  That might make an argument for wearing the 
respirator in the cab, at some point during the life of the tractor.  


Regarding the rest of calibration of the calibration discussion, you should be 
able to separate tree-row volume from your calculations which use row width, 
travel speed and gallons-per minute, to establish a gallon per acre application 
rate.  All the growers we work with have variability in their row spacing.  
Three things we do to address this include minor adjustments to travel speed, 
flipping over/turning on or off spray nozzles, and use of spray control 
systems.  So, lots of ways to skin that cat, but we finish and think we have it 
set up correctly, we verify by hanging those water/oil-sensitive cards in the 
trees and see if we are satisfied with the coverage. 


I would never trust a site line on a spray tank and it is easy to put more 
water in a tank than what a tank is labeled to hold. Think about any water 
bottle, the 30 fl. oz. mark is about an inch below the top of the bottle.  As 
with a sprayer, if you fill it all the way up, there will be more water in it, 
than what it is labeled to hold.  A good way to check is to calculate the GPM 
flow of the hose you use to fill your sprayer with, then just set a timer to 
accurately fill your tank.  This will help you be sure you are putting the 
correct amount of water in the tank, before you run it out through your control 


Another helpful website is http://sprayers101.com/airblast101/


Several years ago we had some money from EPA to go calibrate sprayers.  We 
worked on dozens of spray scenarios and found applicators were applying 52% 
more water, on average, than what they were reporting.  The number of broken 
nozzles, missing screens, etc. was amazing.  So at the very least, regardless 
of what method you use, calibration helps address some of the basic maintenance 
needs of a sprayer, which is helpful in preventing breakdowns during that first 
primary scab infection at green tip. 










Peter Werts

Specialty Crops Project Manager

IPM Institute of North America, Inc.

211 South Paterson St. 

Suite #380 

Madison WI 53703

Office: 608 232-1410

Cell: 612 518-0319

Fax: 608 232-1440

pwe...@ipminstitute.org <mailto:pwe...@ipminstitute.org> 

www.ipminstitute.org <http://www.ipminstitute.org/> 




From: apple-crop [mailto:apple-crop-boun...@virtualorchard.com] On Behalf Of 
Sent: Thursday, March 2, 2017 9:46 AM
To: 'Apple-Crop discussion list' <apple-crop@virtualorchard.com>
Subject: Re: [Apple-Crop] sprayer calibration debate


Hello Hal,

I don’t think an additional respirator should be needed. After all, the 
respirator in the tractor cab is the same design (only larger) than the one on 
the oral one.

Regarding the theoretical calibration of sprayers, whenever an inspector tells 
me they to do it with water, and to apply that result to a water/chemical 
mixture I have a go at them. Only a regulator who never applied products with 
different viscosities (due to temperature or different mixtures) would pretend 
you can pre-calibrate with more than a 90% accuracy. The fact is the same 
sprayer with different products in it, or water of different temperatures, will 
put our at different rates.


Con (Cornelius) Traas

Room SR2-009,

Department of Biological Sciences,

University of Limerick.

Ph: 061-202905

M: 086-6091998

T: @theapplefarmer


From: apple-crop [mailto:apple-crop-boun...@virtualorchard.com] On Behalf Of 
Hal Wentzel
Sent: 02 March 2017 15:24
To: Apple-Crop discussion list
Subject: Re: [Apple-Crop] sprayer calibration debate


Since I upgraded my tractor this winter, I plan on recalibration and this is 
the method I plan to use.  Adjust the nozzles and the tractor speed until I 
feel I get adequate coverage of the trees.  I will then fill my tank with 50 
gallons of water, and spray it over a prescribed route.  When the tank is 
empty, I calculate the acres sprayed.  From that I can determine the number of 
gallons per acre.  To that number of gallons, I will add the chemical required 
per acre.  Since we are high density, well pruned, I multiply by .7 (captan:  
6# x .7= 4.2 #).  If I travel the same route, I will get the required spray per 


A different question:  my new tractor has an enclosed cab (no more monkey 
suit), with an activated charcoal filter.  What is the opinion on the necessity 
of also wearing a respirator.  EPA would say yes, but are they too cautious.

Hal Wentzel 

Pleasant View Orchard 

Niagara, Wi



On Thu, Mar 2, 2017 at 8:16 AM John Bruguiere <j...@dickiebros.com 
<mailto:j...@dickiebros.com> > wrote:

Hello all, need some healthy practical advice on sprayer calibration.  
Specifically air blast sprayers.  For decades we have measured a block of trees 
to determine acreage, sprayed out tank and determined gallons per acre based on 
what area was covered in tank. For example trees planted at 8 x 18 spacing gave 
us 300 trees to acre, we sprayed out tank, counted trees and determined that 
our sprayer puts out 2.5 acres per tank.  we used this  to determine amount of 
material to put in the tank etc. All the calibration formulas , I have seen 
require tree row volume(height x row spacing) to be part of equation.  I have 
4-5 different spacings in 100 acres of orchard which makes it more of a 
headache to constantly figure gallons per acre and spray materials needed in 
each different block(thus the reason we simply measured trees per acre). I know 
my speed , i know my gallons per minute but can't find an equation that 
converts this to gallons per acre without tree row volume.

need a simple but effective solution...any takers?

in Virginia we have plums in full bloom, fantasia and red gold nectarines in 
pink and some open blooms, 21 degrees forecasted on friday and saturday night.

God Bless,

John Bruguiere

Dickie Bros. Orchard


On 1/30/2017 6:36 PM, Arthur Kelly wrote:

I agree Mo.  We try and remove trees every year and plant every year.  I did 
use the word can to hedge the productive life of a block.

Sent from my iPhone

On Jan 30, 2017, at 5:48 PM, maurice tougas <appleman.maur...@gmail.com 
<mailto:appleman.maur...@gmail.com> > wrote:



I agree that it's great to be out pruning. I disagree that you should expect a 
longer productive life with high density systems. My goal here is to be looking 
at replanting when the orchard reaches twenty years or so. New varieties, 
strains of varieties and improved planting system encourage 5% renewal in my 


My best to you

Mo Tougas


On Mon, Jan 30, 2017 at 1:27 PM, George Greene <cortla...@icloud.com 
<mailto:cortla...@icloud.com> > wrote:



Your comment makes sense to me.  Right now I have a cold and I fell on the ice 
on Dec. 29th and I am still suffering.  Pt may help but it may take a while.


I suppose that you are enjoying the warmer weather.


Be well, George


On Jan 30, 2017, at 12:43 PM, kellyorchards <kellyorcha...@gmail.com 
<mailto:kellyorcha...@gmail.com> > wrote:


Ruminations after a morning pruning.  The weather is ideal.  The temps are in 
the high 20's, the wind is light and the sun is shining.  Weather like this is 
why we live here.  Permanent limbs ultimately and inevitably get too large.  
This is why high density systems can have a longer productive life than less 
dense orchards.





Art Kelly
Kelly Orchards
Acton, Maine

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George Greene

68 Willow Lane

Wiscasset, ME 04578

207-882-8074 <tel:%28207%29%20882-8074> 

cortla...@icloud.com <mailto:cortla...@icloud.com> 




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Maurice Tougas
Tougas Family Farm
Northborough,MA 01532

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Hal Wentzel

Pleasant View Orchard

W6050 Chapman Road

Niagara, WI  54151


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