It only takes one non-baited trapped fly to determine that they have arrived to the orchard or in your backyard! 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). Apple maggot flies usually emerge first in unsprayed apple trees. Females are capable of laying eggs 7-10 days after they emerge. Then later in the summer (early July-August) mature females begin to immigrate into the edges of commercial orchards or into your yard.
Apple Maggot Soon to Arrive
Apple Maggot Arrival Time
It's time to set apple magott (AM) traps in your trees or orchard if you have not done so already. I usually do this around July 4, but with the extreme heat and drought we have experienced, I delayed a few days. We are at about 1290 DD from January 1 as of today, and I trapped our first fly July8, so if you have not done so, it is time to get out the apple maggot traps and get them set.
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.
Most commercial apple orchards have no indigenous populations of AM. AM infestations in commercial orchards result from flies immigrating into the orchards from outside sources. AM volatile-baited sticky spheres should be deployed along the edges of commercial orchards that are closest to outside sources of apple maggots (abandoned orchards, unsprayed homeowner’s trees, feral apple trees). Check traps at least once/week.
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.
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.
Several insecticides can be used for apple maggot control including those used for codling moth control like acetamiprid or spinosad. Acetamiprid is a soft, conventional control and may still be available as Ortho Flower, Fruit & Vegetable Insect Killer. Ortho has phased this product out of production, but there are still some bottles available on eBay or The Seed Ranch. This is a concentrate product that contains .05% acetamiprid, a synthetic organic compound of the family of chemicals that acts as translaminar insecticides. These penetrate leaf tissue and remain there for the insect to digest, but do not travel any further than the leaf and wash off in about 14 days. Acetamiprid is a contact insecticide for sucking-type insects and can be applied as a foliar spray. It 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.
An all natural approach is available in the form of Bonide’s Captain Jack’s Dead Bug Brew. 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:
This publication contains pesticide recommendations that are subject to change at any time. These recommendations are provided only as a guide. It is always the pesticide applicator's responsibility, by law, to read and follow all current label directions for the specific pesticide being used. Due to constantly changing labels and product registration, some of the recommendations given in this writing may no longer be legal by the time you read them. If any information in these recommendations disagrees with the label, the recommendation must be disregarded. No endorsement is intended for products mentioned, nor is criticism meant for products not mentioned. The author assumes no liability resulting from the use of these recommendations.
Home Orchard Management @ Royal Oak Farm Orchard
Home Orchard Management @ Royal Oak Farm Orchard is a blog for the home fruit tree grower providing information about fruit tree management, fruit tree pruning & training and Integrated Pest Management from the IPM Specialist and Certified Nurseryman at Royal Oak Farm Orchard, a 20,000 tree apple orchard and agri-tourism operation located in Harvard, Illinois.
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