How to Manage Pests
UC Pest Management Guidelines
Pear
Apple Maggot
Scientific name: Rhagoletis pomonella
(Reviewed
11/12
, updated
11/12
)
In this Guideline:
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Adult flies are somewhat smaller than house flies and have clear wings with
characteristic black bands, a pronounced white spot on the back of the thorax,
and a black abdomen with light-colored crossbands. Female flies have four
crossbands on the abdomen, and males have three. Larvae are cream-colored
maggots with a blunt posterior and a tapered front end that contains two black
mouth hooks. The apple maggot is closely related to the walnut husk fly and
cherry fruit fly. The adult fly can be distinguished from these other pests by
the banding on its wings. It is difficult to distinguish apple maggot from
snowberry maggot, a close lookalike that occurs throughout California but does
not attack apples and pears.
Apple maggot is a native pest of the eastern United States and
Canada. In 1979 it was discovered in Oregon and later in California (Mendocino
and Lake counties), Washington, and other western states. Hawthorn and apples
are favored host plants, but cherries, pears, and other fruits have also been
attacked.
Apple maggot may infest pears that are
adjacent to infested apple trees. Female apple maggot adults deposit eggs
singly under the pear skin, using a needlelike ovipositor at the tip of the
abdomen. Principal injury is caused by burrowing larvae that feed on pear flesh. Browning
of the trails occurs as the pear responds to this injury and bacteria associated with maggots
cause fruits to rot internally.
Apple maggot is a minor pest of pears. If spray treatments are needed, they are
aimed at the adult stage.
Biological Control
Because the
apple maggot feeds within fruit, biological control agents have not been very
effective.
Organically Acceptable Methods
Baited
sprays such as GF-120 are organically acceptable.
Monitoring and Treatment Decisions
Emergence
and dispersal of adult flies must be carefully monitored to effectively time
treatments. Sticky traps, including yellow rectangles and red spheres, are used
in other areas to monitor adults and time treatments. Unfortunately, only
provisional economic thresholds are available for apple maggots, even in areas
where it has long been a pest. You can detect the first emergence of adults by
hanging yellow sticky traps in abandoned orchards or unsprayed apple trees in
infested areas. To detect the beginning of egg laying, hang red sticky spheres
in apple trees, then treat as soon as the first fly is found. In Oregon, where
some orchards are treated regularly for apple maggots, the first maggot spray
is applied 7 to 10 days after the first fly has emerged. Later sprays follow at
10- to 14-day intervals as long as adults are active and are being caught in
traps.
Common name |
Amount to Use** |
R.E.I.+ |
P.H.I.+ |
(trade name) |
(conc.) |
(dilute) |
(hours) |
(days) |
|
The following materials are listed in
order of usefulness in an IPM program, taking into account impact
on natural enemies and honey bees. When choosing a pesticide, also
consider information relating to environmental impact. Not all registered pesticides are listed. Always read label of product being used.
|
|
A. |
SPINOSAD |
|
(GF-120)# |
Label rates |
4 |
0 |
|
MODE OF ACTION GROUP NUMBER1: 5 |
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COMMENTS: Most effective for small populations |
|
B. |
CORN GLUTEN MEAL |
|
(Nu-Lure Insect Bait) |
1-3 pt/acre |
N.A. |
0 |
|
. . . PLUS . . . |
|
SPINOSAD |
|
(Entrust) |
2-3 oz |
0.5-0.75 oz |
4 |
7 |
|
(Success) |
6-10 fl oz |
2-3.3 fl oz |
4 |
7 |
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MODE OF ACTION GROUP NUMBER1: 5 |
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COMMENTS: Do not apply more than 9 oz/acre/crop of Entrust or 29 fl oz of Success/acre/crop. |
|
C. |
PHOSMET |
|
(Imidan) 70W |
4 lb |
1 lb |
24 |
7 |
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MODE OF ACTION GROUP NUMBER1: 1B |
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COMMENTS: Apply alone or tank-mixed with Nu-Lure Insect Bait. |
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UC IPM Pest Management Guidelines:
Pear
UC ANR Publication
3455
Insects and Mites
L. G. Varela, UC IPM Program, UC Cooperative Extension, Sonoma County
R. B. Elkins, UC Cooperative Extension, Lake County
R. A. Van Steenwyk, Insect Biology, UC Berkeley
C. Ingels, UC Cooperative Extension, Sacramento County
Acknowledgment for contributions to Insects and Mites:
C. Pickel, UC IPM Program, UC Cooperative Extension, Sutter/Yuba counties
P. W. Weddle, Weddle, Hansen & Associates
R. Hansen, Weddle, Hansen & Associates
P. Chevalier, United Ag Products, Ukiah
M. Hooper, Ag Unlimited, Lakeport
B. Knispel, Pest Control Adviser, Upper Lake
T. Lidyoff, Purity Products, Healdsburg
G. McCosker, Harvey Lyman Agservices, Walnut Grove
B. Oldham, Ag Unlimited, Ukiah
J. Sisevich, AgroTech, Kelseyville (retired)
D. Smith, Western Farm Service, Walnut Grove
B. Zoller, The Pear Doctor, Inc., Kelseyville
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