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April 2004


Each year in early January research personnel, crop consultants, manufactures technical reps, and growers gather together for the Western Orchard Pest and Disease Management Conference in Portland OR.  This conference brings together several hundred people from across the country (and world) to discuss the research and advances that have taken place during the year. It was interesting to note that this year 45% of the presentations dealt with codling moth.  I know that will strike home with a number of us due to our failure to maintain a worm free crop!



A few thoughts from Alan Knight USDA ARS Yakima:


In general, there was almost no cessation in egg laying by codling moth in orchards during the season.

  • OP susceptible populations are well controlled for more than 21 days with rates as low as 1 lb.Guthion per acre.

  • The intermediate (resistance) population survived a 2 lb rate after 14 – 17 days.

  • The most resistant populations begin to survive a 2 lb spray after only 7 – 10 days!

  • Our most resistant population, (probably similar to most orchards sprayed regularly with Guthion) has a shifted emergence curve in the spring.  Resistant individuals emerge later, thus the population has a long tail in its emergence.

  • It appears that the most resistant individuals emerge at the end of the curve.


 The “old standard” four cover spray program for codling moth is based on two generations of codling moth per season and Guthion residual of 21 days. 

1st cover - Timed when 3% of the first generation eggs have hatched. 

2nd cover – 21 days after the first cover.  Based on an effective Guthion residual of 21 days.  These two sprays protected you from the first generation of worms. 


3rd cover - The timing for the third spray was calculated to be at 7% egg hatch of the second generation. 

4th cover -The fourth spray was then applied 21 days (Guthion residual) later.  The third and forth sprays covered the second generation. 

This program works well as long as population  pressure is not excessive, the season doesn’t stretch out too long, or your population isn’t resistant to Guthion.  If the codling moth population in your orchard is resistant to OP’s and your program is based on Guthion then read Alan’s comments again!  It may be appropriate to switch classes of insecticide and plan a more aggressive control program.



There are several classes of new insecticides with codling moth activity.


Similar to and modeled after natural nicotine. Acts on the central nervous system. The lion’s share of new registrations are coming from this class.  Provado a member of this class, first registered in the U.S. in 1992 is possibly used in the greatest volume globally of all insecticides.    This class of material may flare mites.


Assail –

  • Strongest new material, comparable to Guthion.

  • The target pest is impacted through both contact and ingestion. 

  • Very safe to bees. 

  • Add 1% oil to help with mite control.

  • Has activity on aphids (wooly, green apple, and rosy), leafhoppers and mealy bug.  Not very good on Leafrollers. 


Calypso –

      -Will require 3 –4 applications per generation to control Codling moth.


Clutch –

  • Arvesta Corp expects registration for 2004

  • Similar to Assail in activity and use

  • May not be as strong as Assail for CM??????



Granulosis –

I discussed this at length in the prior letter, so I’ll skip the review, but consider this material as a possibility in your program.


Growth Regulators:

Molt accelerating compounds (MACs)  These materials are broad-spectrum lepidoptera control agents.

This group of materials has high ovicidal activity.  Time sprays for start of egg laying, not hatch. 

Their mode of action is to accelerate the molting process, and lead to head capsule slippage

Intrepid –  

  • Apply at peak egg lay (150-250 DD following biofix) followed by a second application in 10 –15 days.

  • Activity against CM & OBLR.

  • Can exhibit up to 18 days residual.

  • May require 3 applications per generation. 

  • Great choice to supplement mating disruption. 

  • Excellent control of OBLR. 

  • Use of a spreader/sticker recommended. 

  • Safe on bees.

Esteem –

     -Best use for our area will be on Pear Psylla


Diamond –

  • Once it’s registered (2005?), this should be a good material for CM

  • Tests show that it’s comparable to Guthion.

  • No mite flare in conjunction with it’s use.


Centuries ago the Chinese discovered that chrysanthemums can help control insects on crops.  The petals contain pyrethrin.  Synthetic pyrethrins were introduced in 1945 and have been evolving since.

Warrior –  A third generation pyrethroid.

Experience has generally been good.  Stay at the high end of the rate and don’t stretch the interval too far.


A Subjective Ranking For Codling Moth Control Materials:


High                       Moderate              Low

       Assail                     Intrepid                  Calypso

      Diamond               Esteem                   Confirm

     Warrior                  SpinTor                  Avaunt


It’s raining (and snowing) outside on my peach bloom as I write this.  In Cedaredge it rained through the night and has put down 1.4” so far. The rain duration and temps are probably satisfactory for an infection period.  IF YOU HAVE BEEN FIGHTING A CORYNEUM BLIGHT PROBLEM IT MIGHT BE WORTH TREATING. 


Great News for organic growers!  Albion Labs has received certification for their line of foliar nutrients.  Metalosate will soon be available in a dry powder formulation for the following elements: CA, MG, ZN, FE, CU and MN.


Time to change a program?  Give me a call to discuss alternatives!

Larry 234-3424



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