Apple Maggot Has Arrived

Fig. 1

In 2021 we have trapped the first apple maggot fly on July 19 at about 1500 Degree Days from January 1.  We are at 1561 DD as of today at 12:20 PM, so if you have not done so,  it is time to get out the  apple maggot traps  and get them set.  I set our orchard's traps a few weeks ago and have started trapping flies.  It only takes one non-baited trapped fly to  determine that they have arrived to the orchard!  The apple maggot (AM) is native to the Midwestern US and is considered a primary pest, along with plum curculio (PC), and codling moth (CM), which have been covered in previous posts. The adult apple maggot fly resembles a small housefly in size, with a black body, eyes of dark red, with the thorax and abdomen having distinctive white or cream colored bands. The AM is distinguished from other similar, and closely related flies, like cherry fruit fly and black cherry fruit fly, by the variation in dark banding on its wings (See Fig. 1).  

Fig. 2

The AM overwinters in the pupal stage in soil. As soil temperatures rise in early spring, development of pupae commences. The adult fly first emergence begins shortly thereafter (early summer, mid to late July this year in upper Illinois). It takes about 7 to 10 days for the female to mature enough to mate and lay eggs.  So there is a 7 - 10 day window for spraying prior to egg laying.  A feeding and mating period (pre-oviposition) during this 7-10 days is followed by egg laying directly under the skin of the apple. Females may deposit eggs over an approximate 30 day period laying as many as 300-500 eggs.

Fig. 3

Egg-laying punctures cause dimples and distortion in the outer flesh of fruits. These punctures appear as pinpricks on the fruit surface. Larvae tunnel throughout the fruit leaving irregular trails.(Fig. 2) As eggs hatch, larvae funnel through fruit flesh leaving a winding brown trail.(Fig. 3)  Egg laying usually ceases in early to late August; however, it may continue longer if drought conditions exist throughout August.

Monitoring For Apple Maggot

Fig. 4

When monitoring for AM, the apple maggot fly tends to show a preference for golden delicious varieties, but no variety is immune from attack.  Sticky red spheres are effective monitoring devices for adult AM flies (Fig. 4). Females are attracted to the sphere for mating and egg laying activities and are trapped by the sticky coating. Hang traps shortly before expected adult emergence (early july in upper Illinois). First emergence may be detected by checking traps daily until the first fly is spotted on the non-baited trap. 

Hang the sphere in the proximity to fruit at eye level on the perimeter of the south or southeast side of the tree. Attach the ball in a sturdy stem about 1 foot above a fruit cluster of approximately 6-10, cleaning out the foliage and other fruit for at least 18 inches to sides and top of the trap so it is easily visible. The spheres attract the insects that come within a few yards of them; therefore, the capture of ONE AM on any one non-baited trap at a time would indicate the need for an immediate control application. The capture of 5 flies on a baited trap would  indicate the need for an immediate control application. Once the pesticide is applied, AM captures are disregarded for the period during which the protective spray is effective (varies according to pesticide used).  Trap kits are available at Gardens Alive by folowing this link, Gardens Alive.

Control for Apple Maggot

Fig 5.

Several insecticides can be used for apple maggot control including those used for codling moth control like   and/or spinosad.  Acetamiprid is a soft, conventional control and may still be available as  Ortho Flower, Fruit & Vegetable Insect Killer (Fig. 5).  Ortho has phased this product out of production, but there may still be some bottles available at local retailers.  This is a ready to use product that contains .006% acetamiprid, a synthetic organic compound of the family of chemicals that acts as neonicotinoid insecticides. Acetamiprid is a contact insecticide for sucking-type insects and can be applied as a foliar spray or a soil treatment. Acetamiprid acts on a broad spectrum of insects, including aphids, thrips, plum curculio, apple maggot and Lepidoptera, especially codling moth.  When sprayed in the evening at sunset, it will not harm bees or other beneficial insects.  Be sure to follow all label directions on the bottle for proper application.

Fig. 6

An all natural approach is available in the form of Bonide’s Captain Jack’s Dead Bug Brew (Fig. 6).  Captain Jack's Deadbug Brew® contains Spinosad (spin-OH-sid), a product first isolated from a naturally occurring soil dwelling bacterium that was collected on a Caribbean island from an abandoned rum distillery. Deadbug Brew® kills bagworms, borers, beetles, caterpillars, codling moth, gypsy moth, loopers, leaf miners, spider mites, tent caterpillars, thrips and more! Use on fruits, vegetables, berries, citrus, grapes, nuts and ornamentals and approved for organic gardening.

As always, be sure to follow all label directions on the bottle for proper application.

For additional information, see the following fact sheets and guides  which are available from local university extension services:

https://ecommons.cornell.edu/bitstream/handle/1813/43071/apple-maggot-FS-NYSIPM.pdf?sequence=1&isAllowed=y

http://extension.psu.edu/plants/tree-fruit/insects-mites/factsheets/apple-maggot

https://www.extension.purdue.edu/extmedia/ID/ID-146-W.pdf

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