Codling Moth – Facts for Fancy Fruit

Codling Moth

Codling moths are flying in some parts of the state. Place your pheromone traps in the orchard during bloom. I have not yet caught any in my traps but expect to soon. We define biofix as the first sustained flight of moths. Therefore, we don’t determine biofix when that first moth shows up in the trap, but rather when we have caught 3-5 moths. That way we know that the general population of moths is active. Codling moths have a developmental threshold of about 50o F, which means that they don’t develop at temperatures below 50. To calculate degree-days, we just take the mean of the high and low temperatures for that day and subtract 50. There are a couple of tricks to those calculations. First, if the low temperature is below 50 and the high is above, adjust the low to 50 before calculating the mean. Second, if the high is above 85, adjust it down to 85 before calculating the mean. This is because they don’t develop faster when temperatures are above 85. Once I reach biofix, I will again tweet out my daily degree-day calculations. If you want to follow my tweets, you can do so at Rick Foster@PurdueFVInsect.

If you look at the table on page 31 of the Midwest Fruit Pest Management Guide, you can see the proper timing for various insecticides for codling moth control. Timing is very important for codling moth control. The closer you can make your application to optimal timing, the better your control will be.

It is common for the first spray for codling moth to coincide with the first cover spray, which is also for control of plum curculio. If so, you should choose a product that will effectively control both pests. For example, Avaunt may be a good choice for plum curculio control at petal fall, but it would probably not be a good choice for the next spray, which needs to control plum curculio and codling moth. Other than the pyrethroids (see article in the first issue of FFF for 2017), Imidan and Assail are probably the best products for control of both pests.

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