Apple Maggot Fly Arrival - Ask Extension
To: U of M Apple Experts and Entomologists:
I have been bagging my apples to protect them from the apple maggot fly for the past 10+ years. I usuall...
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Apple Maggot Fly Arrival #849283
Asked September 10, 2023, 7:15 AM EDT
To: U of M Apple Experts and Entomologists:
I have been bagging my apples to protect them from the apple maggot fly for the past 10+ years. I usually do this during the last two weeks in June. However, last year and again this year there were already signs of apple puncture by June 15th.
Do you think the lifecycles and timing is changing? Or do you think that the extreme heat the past couple early Junes has the cycle speeded up temporarily? Are you seeing this across the state?
Please let me know what you think.
Meeker County Minnesota
Expert Response
Hello,
Apple maggot development, like many insects, is driven by temperature. The warmer it is earlier in the year, the sooner the insect will develop and emerge. The warm spring likely meant this insect, as well as some others, came out earlier according to the calendar, but on time according the the temperatures thresholds that drive their development.
Entomologist use the term "degree days" to capture this. For apple maggot, it will grow and continue it's lifecycle anytime it is over 50 degrees. By measuring the amount of time over this 50 degree threshold, we can figure out where apple maggot will be at in its lifecycle. You could use degree day tools in the future if we have another warm spring to figure out when to bag your apples.
Degree day info for apple maggot and other pest: https://hort.extension.wisc.edu/articles/degree-days-common-fruit-vegetable-insect-pests/
You can avoid doing the math by entering apple maggot's info here: https://agweather.cals.wisc.edu/thermal-models/dd-map
Want to avoid math altogether? You could also put out an apple maggot trap (red orb covered in something sticky) and check it for apple maggots, then bag your apples after your first catch. More info on traps here: https://extension.umn.edu/yard-and-garden-insects/apple-maggot#sticky-traps-1814712
Marissa Schuh
Horticulture Integrated Pest Management Educator
Apple maggot development, like many insects, is driven by temperature. The warmer it is earlier in the year, the sooner the insect will develop and emerge. The warm spring likely meant this insect, as well as some others, came out earlier according to the calendar, but on time according the the temperatures thresholds that drive their development.
Entomologist use the term "degree days" to capture this. For apple maggot, it will grow and continue it's lifecycle anytime it is over 50 degrees. By measuring the amount of time over this 50 degree threshold, we can figure out where apple maggot will be at in its lifecycle. You could use degree day tools in the future if we have another warm spring to figure out when to bag your apples.
Degree day info for apple maggot and other pest: https://hort.extension.wisc.edu/articles/degree-days-common-fruit-vegetable-insect-pests/
You can avoid doing the math by entering apple maggot's info here: https://agweather.cals.wisc.edu/thermal-models/dd-map
Want to avoid math altogether? You could also put out an apple maggot trap (red orb covered in something sticky) and check it for apple maggots, then bag your apples after your first catch. More info on traps here: https://extension.umn.edu/yard-and-garden-insects/apple-maggot#sticky-traps-1814712
Marissa Schuh
Horticulture Integrated Pest Management Educator
Thank you so much! That is exactly the information I was looking for!!
On Sep 11, 2023, at 9:34 AM, Ask Extension <<personal data hidden>> wrote:
