March 2012

 

This is the final season for the use of Guthion/azinphosmethyl products, in accordance with the scheduled phase-out guidelines previously established by EPA. In both apples and pears, a total of 3 lb formulated product/A is allowed in 2012, the same as in 2011.  In cherries, it's 1.5 lb formulated product/A for 2012.  Read your labels carefully. (These products had been previously excluded from use on peaches,nectarines, plums, prunes, and apricots.)

 

As long as we’re on the “hit list” topic, here’s the scoop on endosulfan. On November 10, 2010, EPA published a Federal Register notice announcing the cancellations, voluntarily requested by the registrants and accepted by the Agency, of pesticide products containing endosulfan. This order followed an August 18, 2010 Federal Register notice announcing the Agency's receipt of requests from all endosulfan registrants to cancel all 30 registered endosulfan pesticide products.

As of July 31, 2012 all use of endosulfan is canceled for: Stone fruits including Apricot, Nectarine, Plum, Prune,Peaches, Sweet cherry and Tart cherry.

As of July 31, 2013:  Pear          July 31, 2015: Apple

 

I am not insensible of the impossibility of pleasing all, but I would not willingly displease any; and for those who take offence where none is intended, they are beneath the notice of

Your Humble Servant,          Silence Dogood (AKA Benjamin Franklin)

 

The following is from an article written by Dave Roseberger a pathologist in New York.

Copper fungicide/bactericide sprays have proven useful for managing fire blight of apples and pears, peach leaf curl and bacterial spot on peaches and nectarines, and bacterial canker on cherries and apricots. Copper sprays control plant pathogens because copper ions denature proteins, thereby destroying enzymes that are critical for cell functioning.  However, copper ions are non-selective. If copper ions enter plant tissues, they can kill plant cells as well as cells of fungal and bacterial pathogens. The outer protective layers on plants (i.e., bark woody tissues, cuticle and epidermal cells on leaves and fruit) prevent copper from penetrating and killing host tissue, whereas bacterial cells and fungal spores landing on trees are more directly exposed to the copper ions on the surface of plants that have been treated with copper. Copper can kill pathogen cells on plant surfaces, but once a pathogen enters host tissue it will no longer be susceptible to copper treatments. Thus, copper sprays act as protectant fungicide-bactericide treatments, but copper sprays lack post-infection  activity.

 

The oldest copper product used in agriculture is copper sulfate, which was used in the early 1800s as a seed treatment for wheat.  Because of its high solubility in water, copper sulfate can cause phytotoxicity even at relatively low application rates, because a large quantity of copper ions will be present on treated plant surfaces anytime water is present. The high solubility also means that copper sulfate residues can be rapidly removed by rainfall. Copper products registered for tree fruits are almost all “fixed coppers” that have low solubility in water.  When these fixed copper products are mixed with water in a sprayer, the spray solution is actually a suspension of copper particles, and those particles persist on plant surfaces after the spray dries. Copper ions are gradually released from these copper deposits each time the plant surface becomes wet. The gradual release of copper ions from the copper deposits provides residual protection against plant pathogens. At the same time, the slow release of copper ions from these relatively insoluble copper deposits reduces risks of phytotoxicity to plant tissues.

 

Following are a few additional concepts relevant to using copper products on tree fruits:

  • Solubility of fixed coppers increases under acidic conditions. As a result, copper sprays will become more phytotoxic if they are applied in an acidic solution.  Acidifiers such as Phos acid should not be tank-mixed with copper fungicides.

  • Copper sprays generally cause more phytotoxicity to the sprayed foliage when applied under slow-drying conditions as compared with rapid-drying conditions. This concern is not relevant for delayed dormant or green tip applications.

  • The objective of delayed-dormant and green tip applications on tree fruits is to generate a copper residue in the tree that will persist and provide disease control that extends through leaf development stages where further applications of copper would cause excessive phytotoxicity.

  • We know from years of experience that copper products can be combined with oil in delayed dormant or green tip sprays if oil is being applied to control mites. Using one quart of spray oil per 100 gallons of water may enhance coverage of the wood in these early season sprays, but using higher rates of oil does not "lock in" the copper deposits to enhance residual activity.

 

 

Every spring I get asked “How cold is too cold to spray dormant oil?”  The text book answer is 45ºF.  A bit of common sense also figures in.  Is the temperature on the rise, or decline?  Is it windy, damp, cloudy, etc.  Pay attention to freezing temps during the 48 hour period before application and for 24 – 48 hours after.  If present or predicted, hold off. 

It's common to make an application with a tank mix of several different pesticides and formulations.  There's a specific mixing order that will help keep you out of compatibility problems. 

 

1) soluble packets

2) wettable powders, or water dispersible granules

3) flowables  

4) emulsifiable concentrates

5) oils.  Always , Always , Always add oils last!

 

So what’s my spray date?  That’s a question I get asked often.  How do I know the answer for your orchard?  Biophenometers, traps, experience and a knowledge of the entire region.   Every year in February, I place a biophenometer in Palisade, Olathe, Eckert, Paonia, Rogers’ Mesa and Cedaredge.  A biophenometer is a self-contained hand held 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 pheremone traps for each pest, in each of these areas.  Once I obtain a biofix (the start of continuous 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.  If the population in your orchard is low, it may be advisable to delay a bit, if you farm at the highest elevation in the area you may want to hold off a few days.  If you use GF 120 for WCFF, start a few days early.  If Spintor is your choice for PTB, make sure you’re applying 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.

 

Mistakes are a part of being human. Appreciate your mistakes for what they are: precious life lessons that can only be learned the hard way. Unless it's a fatal mistake, which, at least, others can learn from.    Al Franken

 

Controlling any pest is a matter of:

 

1)      Using the proper material properly.  Choose a material that will do the job.  Is resistance an issue?  Use a high enough rate to do the job or change classes.  Is it a special need and/or timing material?  Buffering, spreader, temperature, life stage issues? 

2)      Proper timing of your application.  All pests have an optimum time to control them.  Do you know that timing for your orchard?

3)      Good coverage.  Have you ever walked behind your sprayer and looked at your coverage, looked at all the dry areas in your tree?  According to Kevin Day a University CA farm advisor, “Excessive speed is probably the biggest roadblock to thorough spray coverage.  Experiments show that sprayers should never travel over two miles per hour.”  I’ll bet that if I were to drive two mph in a race I would lose to every sprayer in the county! 

 

If you’re having trouble with control, then one of the above is the cause.  Don’t assume you know the answer.  Work your way down the list.

 

Modes of action of insecticides have been characterized by the Insecticide Resistance Action Committee (IRAC), and a chart that shows modes of action and groups chemicals with similar modes of action is available on the IRAC web site -- http://www.irac-online.org/teams/mode-of-action/   Where resistance management is a goal, as it should be for fruit growers who use insecticides, rotating among modes of action (not just products that might have the same mode of action) is an important step.  There is a wealth of information at this site regarding resistance management.

 

If you have a hydraulic post driver for sale or rent please call Dave Smith  970-361-8731

 

Equipment for sale?  Equipment wanted?  I’m happy to use this newsletter / mail list as a bulletin board for industry needs.  Let me know and I’ll send it out.

 

Questions?  Please Call!

Larry 234-3424.

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