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May 2010


Send me you e-mail address!  Starting soon I will be sending out alerts for different pest events.  In the past, Dr.Larsen's  "FruitFacts" emails served as an alert that a pest event was coming.  The arrival of each new FruitFacts always caused my phone to ring with questions about specific timing for a particular site.  Due to Dr. Larsen's retirement, the future of FruitFacts is in question.  My plan is to send out a BRIEF note showing where pest developments are, and treatment timings for each.   Please send me an email note asking to be added to the alert list.  Send it to: .  This program is being started as another means of service to Grand Mesa Discount's customers, with the hope that it helps you harvest more clean, quality fruit!

How do I know the spray timing for your orchard?  Biophenometers, traps, experience and a knowledge of the entire region.   Every year in February, I place  biophenometers in Palisade, Olathe, Eckert, Paonia, Rogers Mesa and Cedaredge.  A biophenometer is a self-contained device that works around the clock keeping track of temperature data.  This data is used to track development of your favorite pests.  I also have a network of pheromone traps for each pest, in each of these areas.  Once I obtain a biofix (the start of continuous trap catch) I will note the biophenometer reading and start accumulating degree days.  Each pest has a threshold (a start time) unique to it.  The decision is further refined by pest populations in your block, daily temps just prior to spraying and the choice of materials you plan to use.  For example, if the population in your orchard is low, it may be advisable to delay a bit, if you farm at the lowest elevation in the area you may want to be a few days early.  If you use GF 120 for WCFF, you’ll need to start a few days early.  If Spintor is your choice for PTB, make sure you’re applying it in the proper window and so on and so on.  As new materials become more pest specific and active on a particular life stage, timing becomes more critical.  Every year I work at refining my pool of knowledge that I use to determine spray timings.  I make notes of who suffers pest damage and why.  Damage is not always the result of poor timing.  It can be insufficient spray coverage or the wrong material.  If all the other factors are properly in place then I take a look at adjusting the spray timing.

Have you seen the  2010 Washington State spray guide?  On the first page under new developments is an introduction of their revised codling moth model that is based entirely off of degree days starting January 1st.  The use of a biofix to start the clock has been eliminated!  Spray timings are determined entirely from degree days.  It's very simple!   I compared our spray dates over the last five years to this new model.  In all cases it gave a spray date of within one or two days of the timing we used.  I believe it will work well for our area!  If you would like a copy of the new WSU crop protection guide, let me know, we have a stack of them.

Last month I wrote: "I expect (hope) that soon the skies will clear and bloom will be upon us.  But, if it continues to be wet, stop and consider what disease problems that will mean for your orchard. "   Bloom has mostly come and gone but not so the rain.  I dumped .6" out of my gauge today (15th).  Pay attention to the possibilities of coryneum blight, powdery mildew (all crops), brown rot, and fire blight.

For grapevines the period between bud-break and bloom is the time when vines are most sensitive to herbicide damage.  Pay particular attention to your choice of herbicides, application methods and spray conditions.  Don't have grapes on your place?   Be a good neighbor! 

Check out this website regarding grapevines and herbicides:

"The dictionary is the only place where success comes before work"  Vince Lombardi

Every so often I hear a comment about glyphosate (RoundUp) not working as well as it used to.  It's a fact that certain weed species can build resistance to a particular herbicide.  Over time it can take higher and higher rates to gain control.  Before dumping more glyphosate in the tank, consider this important aspect of your spray program.  The material that makes up 99% of your spray tanks content…..WATER!  Don’t take your water supply for granted. Both the quantity and the quality of spray water are critical factors.  Water is a good solvent and picks up impurities easily.  As water moves through soil and rock, it dissolves very small amounts of minerals and holds them in solution.  Calcium and magnesium dissolved in water are the two most common minerals that make water “hard”.  The degree of hardness becomes greater as their concentration increases.  Both of these elements are present in water as strongly charged positive ions called cations.

These cations can severely “tie up” many herbicides greatly reducing their effectiveness.

Under alkaline (high pH) conditions this problem is more severe because the minerals become even more soluble.  How hard is your water?  Hardness is measured in milligrams per liter:

·         Soft                              0 – 60 mg/L of calcium carbonate

·         Moderately hard          61 to 120 mg/L 

·         Hard                            121 – 180 mg/L 

·         Very hard more than   180 mg/L 


Water samples taken in the Grand Valley:

Canal   275 mg/L  of  CaCo3       pH  7.9

Tap       195 mg/L of CaCo3        pH  7.2

If you farm in the Grand Valley (or about anywhere else in western Colorado), YOUR WATER IS HARD!!!  And IT’S ALAKALINE!!!  Fortunately the fix is easy and inexpensive.  Before you add herbicide to the tank, mix in 10 pounds of spray grade ammonium sulfate per 100 gallons of water.  Ammonium Sulfate will bind to the cations and tie them up before the herbicide can, and as a bonus help acidify the water.  Don’t skip this step, it can significantly increase your herbicides’ performance.  Get the most bang for your buck!



"A strong body makes the mind strong.  As to the species of exercises, I advise the gun.  While this gives moderate exercise to the body, it gives boldness, enterprise and independence to the mind.  Games played with the ball, and others of that nature, are too violent for the body and stamp no character on the mind.  Let your gun therefore be your constant companion of your walks."                                                                          


Thomas Jefferson in a letter to Peter Carr, August 19, 1785  



Questions?   Please give me a call!

Larry  234-3424

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