Time to Begin Apple Maggot Monitoring

Apple Maggot Fly

Fig. 1

Last season we trapped the first apple maggot fly on June 30. at about 1150 Degree Days from March 1.  We are at 982 DD as of today at 10:00 AM, so it is time to get those apple maggot traps set.  It only takes one 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 June in upper Illinois). A feeding and mating period (pre-oviposition) of approximately 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 AM traps, AM’s 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 (mid to late June in upper Illinois). First emergence may be detected by checking traps daily until the first fly is spotted on the 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, capture of ONE AM on any one trap at a time 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).

Control for Apple Maggot

Fig 5.

Several insecticides can be used for apple maggot control including those used for codling moth control like acetmaprid and/or spinosad.  Acetamiprid is a soft, conventional control and is available as  Ortho Flower, Fruit & Vegetable Insect Killer (Fig. 5).  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

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

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

Reference in this blog to any specific commercial product, process, or service, or the use of any trade, firm, or corporation name is for general informational purposes only and does not constitute an endorsement, recommendation, or certification of any kind by Royal Oak Farm, Inc.   People using such products assume responsibility for their use in accordance with current label directions of the manufacturer.
 

Sustained Flight of Codling Moth Established

As I mentioned in a previous post, of all the flying pests we encounter in the upper Midwest, codling moth is one of  the insect pests needing to be controlled the most.  Even though codling moth flight began several weeks ago, due to the cold nights and days in between, we had not been able to establish a sustained flight until this past weekend.   The first sustained flight of two days in a row with 5 or more moths in a trap, was on June 2, this past Saturday.   That first sustained flight date now becomes our biofix date.


Armed with a biofix of June 2, and by calculating the degree days from that biofix date, we can now begin our countdown for our first spray against the "proverbial worm in the apple"!  The degree days are a measure of temperature occurring during a day. They are useful for predicting activity of codling moth (and many other insects) because insects are cold-blooded and their development follows temperature.

 

Degree-days are determined by use of the average temperature for a day (maximum temperature + minimum temperature/2) and subtracting it from the base temperature  at which the insect does not develop. For the codling moth a base temperature of 50°F is used. (Temperatures above 88°F are upper thresholds for codling moth  activity  and  should  not  be  included in  degree  day accounting.)  As an  example, a day when the high temperature was 80°F and the low temperature was 60°F,  then 20 degree days would accumulate [(80 + 60/2)- 50]. 

 

Here is a Detailed Growing Degree Day Model for Codling Moth.  Following the model, we know that at 100 degree days after the biofix date codling moths begin to lay eggs and those eggs begin to hatch at 250 degree days after biofix.  It is this information that aids in the timing of necessary sprays for codling moth so they do not damage fruit.  Growers wishing to time sprays based on egg development and hatch should make an application of an insecticide at 250 DD (base 50 degrees F) after the first sustained capture of males in the sex pheromone traps.  If you have no way of monitoring these temperatures for degree days, I anticipate, given the projected forecast for the next week, that a spray date should be around June 13 or 14.  

 There  are only a very limited  number of spray products on the home garden/ consumer market that are available for managing codling moth in home orchards, as I have mentioned in previous posts. All of these require repeated application, timed for periods when eggs are being laid and are hatching, and thorough coverage of fruit.  Let's review these again.

  

Spinosad. Spinosad is a naturally derived material, produced by soil microbes (active ingredient, spinosyns). Several formulations are available, most of which are allowed to be used in Certified Organic production. Combination with horticultural oil is often useful in increasing control and fruit coverage. Applications should be made at 10-14 day intervals during periods when eggs are hatching. Effects of spinosad on natural enemies of fruit-infesting insects generally are minimal, although some are susceptible.

Acetamiprid.  Acetamiprid is a soft, conventional control and is available as  Ortho Flower, Fruit & Vegetable Insect Killer.  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, translaminar insecticide for sucking-type insects and can be applied as a foliar spray. Translaminar insecticides are absorbed by leaves and can move through the leaf to the opposite surface they contact, but are not truly systemic and do not move throughout the plant. 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.

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

https://ecommons.cornell.edu/bitstream/handle/1813/43086/codling-moth-FS-NYSIPM.pdf

http://extension.psu.edu/plants/tree-fruit/insects-mites/factsheets/codling-moth

As with all spray products, be sure to follow all label directions on the bottle for proper application.  No endorsement of products mentioned is intended nor is criticism implied of products not mentioned.