August 12, AppleTalk Call Summary

AppleTalk Conference Call Summary
Tuesday, August 12th, 2014, 8:00 – 9:00 a.m.
Presenter: John Aue, Threshold IPM.
Moderator: Peter Werts, IPM Institute of North America; questions or comments,

August 12th Call download: Click Here

Pre-harvest scouting priorities
Secondary insect pests minute 4:00
If under control, secondary pests, e.g., white apple leaf hopper, obliquebanded leafroller (OBLR), leafminer, stinkbugs, Japanese beetle, are not likely to become problematic in the coming weeks.

Codling moth 5:55
Continue to monitor codling moth (CM) traps until 1700 DD, base 50, have been reached from first generation biofix. At this time ninety percent of second generation adults will have flown. It is cautioned that declining or spotty numbers before this is likely from insufficient control during first generation. When timing a larvicide application it is recommended to wait until orchard wide trap captures exceed a total of five per week. Once levels exceed threshold begin degree day calculation for a treatment.

If first generation was controlled effectively it is possible second generation may only require one application of a larvicide. To determine if an additional application is necessary inspect traps seven days following an application. The majority of eggs, larvae, from moths that flew during this period will be exposed to a lethal dose of insecticide. Remove all moths and revisit in seven days. The larvicide should provide activity for fourteen days following an application. If trap counts are over threshold, five per week, during the second visit a larvicide will need to be renewed. For larger orchards spot spraying blocks with high traps captures may be an alternative to applying a full cover insecticide. With a very low pre-harvest interval codling moth granulosis virus, e.g., Cyd-x, Virosoft, Madex HP, Carpovirusine, can provide utility. Note: Codling moth have the potential to cause significant damage in a short period of time.

Lesser apple worm 18:40
Damage from lesser apple worm is typically confined to the calyx end of the apple with tunneling approximately a quarter inch deep: IPM newsletter.

Apple maggot 22:20
This year apple maggot (AM) flights can be directly correlated to significant rainfalls, one to two inches of rain have resulted in significant flight of AM. Continue to monitor traps through the first week of September. Review below table for information on commonly used insecticides for second generation CM and AM control. Clean traps 10-12 days after application to determine if a reapplication is necessary.

Click to enlarge image.
Click to enlarge image.

Disease: Apple scab, sooty blotch and flyspeck 30:30
If scab lesions are present on foliage and/or fruit it is critical to maintain fungicide treatments as cooler, wet weather will create desirable conditions for the development of conidia. Use caution if stretching out fungicide, e.g., captan, coverage for more than two weeks if scab is a concern.

Growers with history of summer diseases are recommended to monitor leaf wetting hours. Fruiting bodies can appear post-harvest. It is recommended to apply Captan 80 (captan) at a minimum of 2 lbs. /acre for summer disease. For protection against black and white rot infections, which can occur from wind damage, a minimum of 2.5 lbs. /acre is recommended.

Review of 2014 season: insect and disease 44:00
• Cool weather following bud break influenced the development of black rot and shoot blight.
• Wet weather required a continued renewal of fungicides. Late bloom typically means less applications, this season was an exception.
• Secondary insect pests, e.g., aphids, Japanese beetle, stink bug, spider mites, San Jose scale, spotted tentiform leafminer, were impacted by cold winter and cool spring.
• Increased pressure and damage from plum curculio and apple curculio.
• Borers will become more problematic in the coming years due to the abundance of weakened or dying trees from winter injury and black rot infections.

The changing landscape of tree fruit IPM 53:20
The orchard is a dynamic landscape which is in a continuous state of flux. It is crucial to recognize its’ volatile nature with the changing variables of pesticides, insects, disease and climate. Growing a crop that is not native to this continent adds to the unpredictability of each season. New insects and diseases will continue to show up and it is important to document new observations and share with fellow growers and professionals to better prepare for the future. Scouting fruit during harvest provides growers a unique opportunity to plan and study for the future.

Additional articles and resources
• Preparing for second codling moth flight. Thaddeus McCamant. Minnesota Department of Agriculture Fruit IPM Update #11. August 7, 2014. IPM newsletter