I don't know about your winters, but mine seem to get shorter and shorter every year. It will be spring before I know it, and that brings codling moth season with it. Here's a few thoughts about registration changes and planning an effective control program. Like it or not, Guthion (azinphos methyl) is on it's way out. For 2007 the same label you used in 2006 will remain. As it stands today, EPA's ruling states that (on Apples, Pears & Cherries) for 2008 & 9 you will be allowed 2 applications with a maximum of two lbs A.I. (active ingredient) or a total of four pounds of product per acre per season. For 2010 – 12 the allowance will be cut in half. One application of one lb A.I. for the year.
Traditional first cover timing with Guthion has been at 250 degree days or about 3% egg hatch. If you figure on a 21 day residual for this application it will run out at about 500 DD. Looking at the graph below you'll see that this is midway through the steepest part of the curve for egg hatch. In other words, your protection is weakest when you need it the most! Stretch your first cover out a few days because your sprayer was broke down, or the fishing was incredible and it's easy to see why we end up with damage.
Codling moth control is strictly a numbers game. Moths can live up to three weeks, but most of the mating and egg laying occurs in the first three days of their life. If you start the season with 50 females per acre with one female laying up to 100 eggs, that works out to 5000 larvae looking for a home! Granted, not all of them will survive but it's easy to see how the numbers grow exponentially. If only half survive, and only half of those are females that means that now you have 1250 females laying 100 eggs.......or 125,000 eggs! Any pest population functions under the same numbers game. That is why it's critical to be aggressive early in the season when the population is at it's low point. Every individual that you take out of the population early greatly reduces the numbers later.
Interested in “Nature Safe” organic fertilizer? Please give me a call if you've purchased in the past and havn't heard from me. I'm starting to put an order together. Mike McCarthy of Nature Safe will have a booth at the Hort Show, stop by and say hi.
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If you're interested in the cold hardiness level of peach buds, take a look at CSU's web page. http://www.colostate.edu/programs/wcrc/infopages/ColdHardiness.htm I sent in samples (Newhaven & Cresthaven from Cedaredge & Orchard Mesa) to be run Thursday the 4th. The results should be posted soon.
As of January 1st , Colorado's minimum wage is $6.85 per hour.
The materials and timings for codling moth control will change in your orchard. The newer materials are more specific as to their mode of action and as a rule don't have the residual life of Guthion.
Resistance to a pesticide will always develop over the course of time. Guthion has an amazing track record for as long as it's been around. The new codling moth materials may not fare as well. Resistance occurs through the process of individuals of a pest population surviving an insecticide application. Those individuals go on to breed another generation of resistant individuals. The individuals that are “selected out” each time become more and more resistant with each insecticide application and each succeeding generation. One of the principal methods to combat resistance is to rotate chemistry classes of insecticides. I've listed a few classes and associated products.
Organophosphates: Guthion, Imidan, Lorsban
Neonicotinoids: Assail, Calypso, Provado
IGR's (insect growth regulators): Intrepid, Rimon, Esteem
Pyrethroids: Warrior, Asana
Biologicals: Virosoft, DiPel
Spinnosyns: SpinTor, Entrust
Use the same class of insecticide for and entire generation (½ of the summer) then switch to a different class for the next.
So here's a suggested program:
At 150DD apply an IGR effective against eggs. This will remove the leading edge of the population.
At 350DD apply a pyrethroid or an organophosphate. Using a 10 – 21 day residual (depending on material used), repeat applications until the first generation is complete.
At start of the second generation (+/- 1300DD) use a neonicotinoid. Continue with this product for the rest of the generation.
A tank mix of an IGR and one of the other classes will give you two modes of action for a much stronger punch. How aggressive you need to be with your program depends on the how much codling moth pressure you're dealing with.
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Hope to see you at the Hort Show!