In this Issue:
VEGETABLE NEWS
STRAWBERRY NEWS
Strawberry Sampling Data from MDA and Grower Cooperators
A Note on Pesticide Registration in MN
APPLE NEWS
Codling Moth Management
| Vol 2 No.5 | June 6 , 2005 |
Codling Moth (Cydia pomonella) and Pesticide Management Options
Damage
Codling moth (CM) (Cydia pomonella) larvae are fruit feeders. There are two types of CM injury: superficial stings and internal injury to fruit. Superficial stings occur when larvae penetrate the fruit skin but are unable to continue inward due to some factors, which could include unsuitable weather, predation and insecticide sprays. This type of injury is common with first generation larvae. Internal injury results when larvae successfully penetrate apple skin making deep entry into the fruit core. The developing larvae burrow within the fruit leaving frass behind. Larvae may also feed on seeds of the fruit.
Management
Monitoring: The adult flight of CM is monitored using pheromone-baited traps. Various types of traps are available, including wing (Pherocon 1CP), and delta traps (Pherocon VI). These traps have been evaluated in Minnesota and results suggest that the delta trap is more efficient for monitoring CM. The recommendation is to divide an orchard into blocks of 5 - 10 acres depending on tree size, age, variety, and pest pressure history. Use 1 trap per orchard block. Place the trap at eye level on the south side of the tree around the center of a block. The recommended action threshold is 5 moths per trap over time (cumulative trap count).
Pesticide management options: Different classes of insecticides are currently available for CM control. They include standard (broad-spectrum) pesticides (e.g. Imidan), and reduced-risk pesticides (e.g. Confirm, Bt , Spinosad). The timing of application of treatments against CM depends on the material being used and the target pest stage(s). Most available pesticides are targeted against the larvae although there are some that also affect the eggs. The wisdom is to apply materials when the target pest stage is present. Treatment decisions against CM are usually based on trap catch results and/or degree-day models. One concept important for CM management is Biofix. This is the date when the first moth is trapped provided moths are trapped on the next two trapping dates. Biofix marks the beginning of sustained CM flight. CM action thresholds are related to Biofix. A CM management model developed by Michigan State has been modified for use in Minnesota (See table below). To use this model: start counting degree days from the date of the first sustained moth catch or Biofix. If using standard materials that target the larvae (e.g. Imidan, Guthion), apply first spray at about 250 DD (base 50ºF) from Biofix. Apply a second spray 10-14 days after first spray (if necessary). Growers using insect growth regulators should apply the first spray at 100 DD after Biofix (just before egg hatch).
Action Thresholds for Codling Moth Using Different Materials
DD 50 (post-biofix) |
Event |
Action if Using Materials that target larvae (e.g. Imidan, Guthion) |
Action if Using Materials that target eggs & larvae (e.g. Intrepid, Confirm) |
Action if Using Materials that target eggs |
0 = Biofix |
First sustained catches of 1st generation moths |
Set DD (Base 50° F) at 0 |
Set DD (Base 50° F) at 0 |
Set DD (Base 50° F) at 0 |
60 |
Egg laying begins |
|
a) Apply 1st treatment around 150 DD if over threshold.* b) Follow-up treatment 14 days later if over threshold.* |
a) Apply 1st treatment around 100 DD if over threshold.* b) Follow-up treatment 14 days later if over threshold.* |
250 |
Egg hatch (3%) |
a) Apply 1st treatment if over threshold.* b) Follow-up treatment 10-14 days later if over threshold.* |
|
|
1000 |
2nd generation moths |
|
|
|
1060 |
Egg laying begins |
|
a) Apply 1st treatment around 1,150 DD if over threshold.* b) Follow-up treatment 14 days later if over threshold.* |
a) Apply 1st treatment around 1,100 DD if over threshold.* b) Follow-up treatment 14 days later if over threshold.* |
1250 |
Egg hatch (3%) |
a) Apply 1st treatment if over threshold.* b) Follow-up treatment 10-14 days later if over threshold.* |
|
|
*Threshold=cumulative count of 5 moths/trap. Note that cumulative trap count should be set back at 0 after each treatment. All DDs base 50°F. If using mating disruption place dispensers at about 150 DD (pink stage).
(For more information see: www.mda.state.mn.us/ipm/applemanual and www.mda.state.mn.us/biocon/biologycm.pdf)
ACKNOWLEDGEMENTS
Co-Editors: Bill Hutchison ( hutch002@umn.edu), Department of Entomology, University of Minnesota, Jeanne Ciborowski, Minnesota Department of Agriculture, Ag. Resources Management and Development Division, and Suzanne Wold-Burkness ( woldx018@umn.edu), Department of Entomology, University of Minnesota
The Newsletter is published weekly from May through August, cooperatively, by the Minnesota Department of Agriculture (MDA) and the University of Minnesota (U of MN). Reports are posted on the U of MN and MDA web sites on Fridays. If you have suggestions and/or comments, please send your contributions by 4 p.m., Wednesday to Jeanne Ciborowski, 651-297-3217, jeanne.ciborowski@state.mn.us , MDA, 90 W. Plato Blvd., St. Paul, MN 55107-2094. You can access the Newsletter at the U of MN web site in htm format at: www.vegedge.umn.edu/MNFruit&VegNews/mnindex.htm and at the MDA web site in pdf format at: www.mda.state.mn.us/biocon/fruitreports/
Partial funding for this publication is provided through partnership agreements with the Minnesota Fruit and Vegetable Growers Association (MFVGA) and the United States Department of Agriculture – Risk Management Agency (RMA). These institutions are equal opportunity providers.
DISCLAIMER
Reference to products in this publication is not intended to be an endorsement to the exclusion of others which may have similar uses. Any person using products listed in this publication assumes full responsibility for their use in accordance with current manufacturer directions.
The University, including the Minnesota Extension Service, is an equal opportunity educator and employer. ©1999-2004 Minnesota Extension Service, University of Minnesota. All rights reserved. Contact copyright@extension.umn.edu for information on reproduction or use of this material.