Apple Talk Call Summary, August 6th

Apple Talk Conference Call Summary
Tuesday, August 6th, 2013, 8:00 – 9:00
Presenters: John Aue, Threshold IPM.
Moderator: Peter Werts, IPM Institute of North America; questions or comments, .

 August 6th Call download: Here

Sootyblotch, Flyspeck and Fruit Rots
The cool weather is not conducive to fruit rots and summer diseases, and few instances of sootyblotch and flyspeck have been observed in orchard.  In the last few weeks John has seen small fruit rot lesions on fruit which had succumbed to bitter rot.  Bitter rot does not affect leaves or other parts of the tree, but can spread between fruit.  Comparatively, black and white rot lesions that appear on fruit do not spread to other fruit.

How do we differentiate between these three lesions?  Look for the color of the sporulating bodies.  On bitter rot the spores are going to be orange, whereas on black and white rot, the fruiting bodies will be black.  All of these diseases create concentric rings on the fruit as the lesions expand.

Captan may be used as a protectant and has good efficacy by itself, Pristine, Flint, Sovran, Merivon all can help slow down the bitter rot, but should not be used if you have secondary scab present in the orchard.

Where non-chemical controls are desired, hand removal of infected fruit is the only option.

Apple Scab
However, these conditions are perfect to reinvigorate apple scab.  With consistent temperatures in the 60’s and 70’s, new scab inoculum can develop on what have been dormant lesions for most of July.  As we enter into harvest we may likely have fruit unprotected for six to eight weeks and are at risk for pin scab to develop.

Powdery Mildew
Where powdery mildew infected shoots are present the risk of continued infection is only present where the terminal buds have not been set and shoots are still actively growing.  This would likely only be the case on newly planted and other non-bearing trees.  Once the terminal bud has stopped growing, there is no need to continue applying materials for powdery mildew and will not remove the symptoms.

Fungicide, Insecticide and Miticide Pre-Harvest Intervals
All recommendations on pre-harvest intervals are for apples only and may vary for other fruit crops.  Applicators are legally bound to follow the restrictions printed on the label in your possession.  If supplemental labels exist, a copy of this label needs to be in possession of the applicator.  If information on your label differs from what is printed below, your label recommendations supersede the following.

Fungicides

  • Streptomycin has a 50-day PHI and should only be applied in the event of a severe hail or storm which damages fruit and tree tissue.
  • Captan (captan) has a zero-day PHI.
  • Topsin (thiophanate-methyl) has a one-day PHI and not a material of choice if you are concerned about fruit rots.
  • Pristine (Boscalid + pyraclostrobin) has a zero-day PHI and provides good protection against summer disease, scab and fruit rots.
  • All the sterol inhibitors, e.g., Rally (myclobutanil) and Indar (fenbuconazole), have a 14-day PHI, are good for summer disease, but have no activity on fruit rot, e.g., bitter rot.
  • Merivon (fluxapyroxad + pyraclostrobin) has a zero day PHI.
  • Flint (trifloxystrobin) 7-day PHI and Sovran (kresoxim-methyl) has a 30-day PHI.
  • Luna Tranquility (fluopyram + pyrimethanil) and Inspire Super MP (difenoconazole + cyprodinil) have a 72-day PHI.
  • Luna Sensation (fluopyram + trifloxystrobin) has a 14-day PHI.
  • Fontelis (penthiopyrad) has a 28-day PHI.
  • Scala (pyrimethanil) and Vangard (cyprodinil) has a 72-day PHI.

 Insecticides and Miticides

  • Acramite (bifenazate) and Envidor (spirodiclofen) have 7-day PHI.
  • Oil and it is good weather for using oil and has a zero-day PHI.
  • Danitol (fenpropathrin), Zeal (etoxazole), Vendex (fenbutatin-oxide), Kanemite (acequinocyl) have 14-day PHI.
  • Group 21A, e.g., Nexter (pyridaben) has 25-day PHI, Fujimite/Portal (fenpyroximate) have 14-day PHI
  • Apollo (clofentezine) has a 45-day PHI.
  • Savey (hexythiazox) has a 28-day PHI.
  • Agri-Mek (abamectin) has a 28-day PHI.
  • Admire Pro, Alias and Montana (imidacloprid) has a 7-day PHI.
  • Assail (acetamiprid) has a 7-day PHI.
  • Calypso (thiacloprid) has a 30-day PHI.
  • Belay (clothianidin) has a 7-day PHI.
  • Imidan (phosmet) has a 7-day PHI.
  • Diazinon (diazinon) has a 21-day PHI.
  • Sevin (carbaryl) has a 3-day PHI.
  • CYD-X (Cydia pomonella granulosis virus) has a 0 PHI.
  • Voliam Flexi (chlorantraniliprole +thiamethoxam) has a 35-day PHI.
  • Voliam Xpress (chlorantraniliprole + lambda-cyhalothrin) has a 21-day PHI.
  • Altacor (chlorantraniliprole) has 5-day PHI.
  • Delegate (spinetoram) and Entrust (spinosad) have a 7-day PHI.
  • Intrepid (methoxyfenoxide) and Rimon (novaluron) have 14-day PHI.
  • Belt (flubendiamide) has a 14-day PHI.
  • Movento (spirotetramat) has a 7-day PHI.
  • Centaur (buprofezin) has a 14-day PHI.
  • Esteem (pyriproxyfen) has a 45-day PHI.

Insect Management
Borers
American Plum and Dogwood Borer are best managed with a targeted trunk spray.  Insecticides for Lesser Peachtree borer on stone fruit can target adults and larva.  The second generation is flying now and it may be best to wait until after harvest and target with a trunk spray.

Japanese beetle (JPB)
Emergence has been unpredictable this year and slow and we are not out of the woods yet.  However JPB is treated, it will likely not impact pressure next year.  Feeding damage is cumulative and can be problematic, yet there is a large variance in the cultivars targeted by JPB.  We can eliminate excess insecticide use by targeting sprays only to susceptible varieties being infested.

Neem oil may be applied as a repellent, but once a JPB population is established, Neem products are not expected to be very effective.  To achieve knock-down control, choices are limited to pyrethroids and Imidan, including Pyganic (pyrethrins) for organic producers.  Whatever materials is applied, it must be done when JPB are active to be the most effective.  This timing is generally on sunny days and in the afternoon.  Organic producers could target first with Pyganic and then follow up the next day with a neem product as a repellent.

San Jose scale (SJS)
San Jose scale has potential to become a widespread problem in orchards where even low populations have been detected and has a high resistance potential because of the possibility for there to be three generations per season.  However, in 2013 we do not expect a third generation due to the recent trend of cool temperatures.  Typically it is the third generation which explodes from a localized problem to widespread through the orchard.

The second generation of SJS crawlers is beginning to move in southern Wisconsin and expect crawlers in the lacrosse are to be moving now or soon.  Once SJS have set on the fruit and in the whitecap phase, they may still be susceptible to a neonicotinoid such as Assail or Admire, generics including Alias and Montana.  Once the crawlers are black, they will no longer be susceptible to insecticides.

Growers need to be applying double-sided tape to scaffold limbs and be monitoring the fruit.  The yellow crawlers are visible with a nice 10x lens.  If growers have been monitoring SJS and are finding infestations in other portions of the block, then the use of monitoring tapes should be expanded.  There is no established threshold or recommendation for the number of monitoring sites per block. If damage has been found on fruit, but tape has not been collecting scale crawlers, then monitoring should also be expanded.

If a neonicotinoid is applied, growers need to recheck after application to evaluate efficacy.  Fruit and tape also needs to be checked frequently, even after an application that is working, we may still catch some crawlers, but should not see new damage to fruit.  If white caps have disappeared, e.g., empty or otherwise dead, this is a sign the insecticide is working.  If they look healthy, we could suspect resistance or a coverage issue.  It is important to make sure we are adequately checking canopy, fruit and scaffolds for scale.

Codling Moth
Most growers are not yet at peak second generation flight, which should happen around 1300- 1400 from the first generation biofix.  If the traps are quiet, make sure the lures are fresh and keep on top of them.  Most growers are likely to target with a larvacide and with the cool temperatures, it could take 12 to 17 days to accumulate the 250 degree day threshold for treatment at 3% egg hatch.

Apple Maggot
Apple maggots have been emerging consistently now across the region.  Remember unbaited red spheres will lose efficacy as fruit ripens and the hanging fruit will become more attractive.  If you are within a week to ten days of harvest, John suggests moving traps to the next cultivar over from a current trapping location.  If apple maggot are coming out of the ground under the tree close to harvest, we don’t expect the flies to move to other varieties.

Obliquebanded Leafroller (OBLR)
John has started to see OBLR flight and presume that in the southern part of our region we are seeing the second OBLR flight.  OBLR pressure can vary in an orchard and often we can see adults flying while we also see third instar larva.  This suggests a long flight and could still be seeing surface feeding damage in late August and early September.  The timing of this flight may work well depending on what materials are applied for second generation codling moth.  For example using Assail or Calypso for AM and CM will not have an effect on leafrollers.  If Altacor, Delegate/Entrust, Avaunt and Imidan are applied for CM, this will also target OBLR and redbanded leafrollers.  

Stink Bugs
This has been a light year for native stink bugs.  The number of fruit with stink bug like damage has picked up, but generally hard to find.  We may not see stink bugs, but may see damage.  When scouting, look for nice circular depressions.  If we see multiple hits on the same fruit or tree, it would be good to flag and check elsewhere for damage.  Typically by now we expect to see lots of adults.

Spotted Wing Drosophila (SWD)
Spotted wing drosophila trap counts have been increasing through the region since June.  While most of these detections have been in small fruits, male and female SWD have been detected in traps set in peaches in western and southeastern Wisconsin.  Peaches are listed only as a moderate risk to SWD, as SWD is unlikely to be able to target under-ripe peaches.  Peaches that drop, become over ripe, or split are at risk of SWD infestations.  Therefore, cultural practices to remove these from the orchard during and post-harvest are important to minimizing risk of infestations.  Specific recommendations for chemical control and monitoring of SWD are available on the University of Wisconsin SWD website, http://labs.russell.wisc.edu/swd/