top of page



March 2017 


Last week I (Dan) had the opportunity to attend the WSU Fruit School in Wenatchee, WA.  The focus of this school was on organic pest and disease management.  There was a ton of information presented,  here are some takeaway points;


Ken Johnson (OSU), Fire blight  Control -


1) Prior to green tip: Fixed copper sanitation if fire blight was in the orchard last year (5 to 6 lb/ac)


2) Early bloom in apple: Thinning with lime sulfur (plus oil) at 20% and 70% bloom will also provide fire blight protection.


3) Early bloom in pear and post thinning in apple:  Blossom Protect one or two apps. Cover every row.  Blossom Protect needs to be applied immediately after 2nd lime sulfur.  


4) Last applications at full bloom to petal fall, depending on cultivar russet risk; CougarBlight model risk;  Serenade Opti every 2 to 4 days (most fruit safe) Improved control: mix Serenade Opti with Cueva (2 to 3 qts/A) or Previsto (3 qts/A) or Cueva (3-4 qts/A) every 3 to 6 days (least fruit safe) Apples at petal fall: lime sulfur (2 to 4%) to clean up bacteria, yeast, mildew and rot fungi


Miscellaneous fire blight thoughts:

  • Most fire blight populations don’t explode until LATE in the bloom period.  Often it’s straggle bloom that causes the problem.   The take home message is to not slack off protection late in the bloom.

  • Early copper applications push fire blight development back to a later period where there’s less bloom present.

  • Interpretation of a “wetting period” depends on where you grow.  It can range from a rain to a heavy dew.

  • Daily highs of 70 ͦF  pose a moderate risk,  80 ͦF means a high risk of infection.

  • Orchard age is a factor to use in your program.  Older trees can stand a bit of blight.  Young trees call for a more aggressive program



David James (WSU), Conserving Beneficial’s -

1)Habitat modification- create “refugium” (an area where special environmental circumstances have enabled a species or a community of species to survive after extinction in surrounding areas)


2)Sage brush happens to be a good plant to attract beneficial’s


Peter Shearer (WSU), Bio Control is a component of IPM -


1)What is IPM? Integrated Pest Management (IPM) is a knowledge-based, multi-tactic strategy for managing pests. It requires information on pest biology, monitoring plans, thresholds for treatment using various tactics such as biological, chemical, and cultural control and subsequent follow-up evaluation.


2) What is Bio Control?  Bio Control is a component of IPM.  It involves human interactions to manipulate natural enemies’ populations to manage pests. Biocontrol and beneficial’s are a part of the solution, not the solution.   A number of factors like varietal selection, fertilization, pest, and timing of intervention influence the outcome. It’s equally at home in both conventional and organic systems.


3) Three Categories of Bio Control include;

            -Classical (Natural Enemies)

            -Conservation (Refugium)

            -Augmentation (Adding beneficials into the system)



  • Perception is that it’s an all or nothing system, either biocontrol or pesticides.

  • Consumer concern is the driver behind biocontrol adoption, even though ignorance is abundant.

  • How do we “preach” agriculture to educate the public, the next generation, the great masses scrolling through Facebook?  They believe the first thing they read, “like” it then change their buying habits!


Need more to read?  The web address below will link you to the presentations from the 2017 WSU school.  It was an interesting mix of industry folks.  Growers (conventional & organic),  extension,  manufacturer representatives,  and researchers.


Click on the “download” buttons to see each individual presentation.



Spring is the most stressful time of the year for any fruit tree (and grower).  Your orchard is drawing from reserves as it progresses through bloom.  Soil temps are cold and limit nutrient availability.  Fruit size is partially determined by the number of cells each fruit contains.  Cell division occurs immediately after bloom (from 14 to 28 days) when stress is at its peak.  Healthy, well fed, trees are better able to handle and size large crops, survive winter injury, and pull buds through spring frosts.  Next years’ flower buds will be developed this season.  Keeping a tree well fed is a year round program.  Properly timed foliar applications of nutrients can help relieve the stress!

  • Delayed dormant: Zn, Mg & B;    

  • Pink, Petal Fall & Summer: N, P, K, Zn, Mn & CA;   

  • Fall: Zn, B, & N



“A government which robs Peter to pay Paul can always depend on the support of Paul.”

- George Bernard Shaw



Are pests resisting your management? -  An individual organism's genes determine its physical and behavioral traits. When individuals reproduce, they pass along unique combinations of genes to their offspring. Different environments favor individuals with different physical and behavioral traits. Individuals with genes that improve their survival will be more likely to pass along these genes compared to the rest of the population. The mix of genes in a population is called the gene pool. The composition of the gene pool continually changes over time through a process called natural selection.


Repeated use of the same class of pesticides to control a pest can cause undesirable changes in the gene pool of a pest leading to another form of artificial selection, pesticide resistance.


When a pesticide is first used, a small proportion of the pest population may survive exposure to the material due to their distinct genetic makeup. These individuals pass along the genes for resistance (survival) to the next generation.  Subsequent uses of the same pesticide increase the proportion of less-susceptible individuals in the population. Through this process of selection, the population gradually develops resistance to the pesticide. (Excerpt from Fruit Crop Ecology and Management )


The practice of “resistance management” is an endeavor that each of us should be involved in.  As we plan our pest programs (both insect and disease) we need to pay attention to a few key components.



  • The class or group of chemistry a material belongs to.

  • The number of times we use it against a pest, are we using the same class of material against succeeding generations of a pest. 


The goal is to avoid “selecting out” any pest group by doing the same practice over and over.

All pesticides have been grouped by their class of chemistry and assigned a group number by FRAC (fungicide resistance action committee) or IRAC (insecticide resistance action committee).  Pesticide labels now contain the group or class number for each product on the label right above the name.


Asana, Danitol, Warrior and Silencer all belong to the same class of insecticide known as Pyrethroids.  Changing from one of these products to another will not help you with resistance management.  It’s not enough to change names, you have to change classes. 


The same issue is true with fungicides, it’s important to have a thorough understanding of the types and capabilities of the fungicides you use to manage plant diseases. Using the correct fungicide at the right time in the proper amount can often mean the difference between a clean, high quality crop or a significant loss in yield or quality.


Don't let powdery mildew catch you flat footed.   Control is best obtained early in the season, not once you notice it!  Cherries are best treated by starting at petal fall & shuck fall; peaches from bloom to pit hardening and apples before bloom.  There's a wide selection of materials with various modes of action available.  Don't fall into a rut and build resistance in you orchard.  Rotate classes of materials and start early!




bottom of page