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July 2004


Every year at this point in the season I get phone calls from growers wondering if they need to spray a block for codling moth or peach twig borer or, fill in the blank with a pest of your choice.  My response always comes in the form of three questions:


1) What does past experience tell you?  Is this a problem block that you generally have damage in? 

2) Do you see visible signs of damage?  Are there stings on the fruit?  Do you see flagging on the terminals? 



The first two questions usually generate good discussion, the third brings nothing but silence.

Properly maintained traps can help provide the answer to the question, “Do I need to spray, and when?”

Weekly monitoring (counting) will allow you to track development and size of a pest population.  The start of the second generation of codling moth usually is long after the residual from the second cover spray is gone.  This means there may be a period when you can back off a bit. On my orchard the gap between the 2nd cover and the 3rd was 35 days this year.  I was able to delay my 3rd cover because I knew what my moth pressure was and when it started back up.   If you maintain a program based solely on material residual (days from the last spray) it would demand at least one more cover.  What about the second cover for Peach Twig Borer?  It’s highly likely that if you were on target with the bloom and first cover sprays that you won’t need the second summer cover.  A few traps will help the decision making process.


What’s the cost to spray an acre of fruit?  Equipment  $15/Ac,  Labor $10/Ac,  Material  $20 – 30/Ac  Your total cost is in the neighborhood  of  $50/Ac every time you fire up the tractor!  What’s the cost to trap an acre of fruit?  NO WHERE CLOSE! Especially if they help you to skip an application.  TRAPS DON’T COST…..THEY SAVE!!!



Are your workers protected?  According to EPA Worker Protection Standards (WPS)?  I hope so.  After twelve years of this issue lying somewhat dormant on the Western slope it’s time to make sure you’re in compliance.  The enforcement branch of EPA recently made several WPS inspections in Palisade orchards.  The plan is to target the Western Slope for the remainder of the season.  The normal procedure is to make an onsite inspection using a checklist for areas of non-compliance.  Then some time in the next six months to a year you can expect another visit.  By law you have to receive a “Notice of Warning” before you can be fined…..but you better have your ducks in a row when they return.  Remember, EPA’s purpose is worker protection through compliance with the law.  They’re not here to pad their pockets with fines.  They’ll be looking to see that an effort is being made to comply.  Representatives from EPA’s training branch have contacted me about the possibility of conducting a compliance workshop in the area.  I’ve included the letter (in italics) they sent to me.  If this is of interest please respond to them.  They can be a bit flexible on the dates, but they would like to be here before the enforcement folks show up in August.  Let them know if you are in Mesa county or Delta county.   EPA has a compliance packet that they will send you at no cost.  It has a copy of the checklist an inspector will use.  Their toll free number (Denver) is at the bottom of the letter.


A few internet sources for WPS info:   click on WPS in Colorado.  This is a great overview of the program and your requirements compiled by Sandra McDonald, CSU environmental and pesticide education specialist.


GMD has a number of WPS materials including the signs needed to post fields.  Let us know how we can help.


How to Comply with the Worker Protection Standard

Through annual Worker Protection Standard inspections and outreach efforts, the US Environmental Protection Agency's Region 8 Office continues its ongoing effort to safeguard the health of agricultural workers and pesticide handlers across Colorado.

The Worker Protection Standard (WPS) is designed to reduce the risk of illness or injury resulting from workers' and pesticide handlers' occupational exposures to pesticides used in the production of agricultural plants on farms or in nurseries, greenhouses and forests. The WPS requires workplace practices designed to reduce or eliminate exposure to pesticides and establishes procedures for responding to exposure-related emergencies. The requirement to comply with the WPS is included in pesticide label directions. The effective dates for the WPS were phased in over a several year period with all provisions becoming effective April 15, 1994.

The WPS requires that owners of agricultural establishments (orchards) provide certain protections to their workers (this includes workers provided by labor contractors) and pesticide handlers. Specifically, they are required to:

  • restrict entry to treated areas

  • provide notification of pesticide applications

  • post specific information regarding pesticide applications (what, where, and when)

  • assure that workers have received safety training post safety information

  • provide decontamination supplies

  • provide access to emergency assistance (when needed)


Compliance with the WPS has been a national and regional priority for the past several years. Several Western Slope facilities have already been inspected this season and more are expected throughout the remainder of the 2004 growing season.

To assist growers in complying with the WPS, representatives from EPA's Regional Pesticide Program would like to extend a "How to Comply with the WPS" workshop to Western Slope growers. If interested in EP A representatives providing a 1 1/2 hour morning, afternoon, or evening workshop in the Western Slope, please contact Barbara Barron at 1-800-227-8917 extension 6617 or Jaslyn Dobrahner at 1-800-227-8917 extension 6252. A workshop can be scheduled on the Western Slope for the week of July 26, 2004.



Oriental Fruit Moth.  Another reason to have a traps in your orchard, especially if you farm in the Palisade area.  Oriental Fruit Moth (OFM) has moved up on East Orchard mesa.  As this season progresses pay attention to the type of worm damage that you find.  Both OFM and Peach Twig Borer (PTB) favor the stem end as an entry site.  The larvae of PTB feed just under the surface of the fruit while OFM larvae will bore into the fruit and feed around the pit.  OFM and PTB have a different biology and develop at different rates.  OFM emerges in the spring as a moth, PTB emerges in the spring as a larva.  The first generation of OFM larva show up after the emergence of PTB larva.  Just because you’re on top of your PTB sprays doesn’t mean you’ve cleaned up OFM.  The bottom line: From this point on, monitor your different varieties for shoot and fruit strikes.  On shoots, the presence of 3-5 strikes per tree signals the need to treat.  On fruit I would treat at the first occurrence of damage.  Inspect fruit from the top of the tree, this is where damage is most likely to occur!  Most fruit damage occurs once the peach has broken color and starts to ripen.  At this point your choice of treatment materials is very limited due to pre-harvest intervals.  Watching for shoot strikes will give you an earlier warning with a better choice of products to treat with.



Before we know it the 2005 Hort Show will be upon us.  It’s a good chance that WPS will be on the agenda.  Is there a topic (any area) that you would like to see discussed?  The purpose of this meeting is to provide you with information that will make you a more successful grower.   Yours truly is in charge of this years program. Please let me know what would help you!!!





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