WVU Extension Service: The Orchard Monitor: Committed to the Integration of Orchard Management Practices
August 21, 2006

Upcoming Events Meeting Hosts & Sponsors


Pheromone Trap Counts Plant Pathology



September 4. - The West Virginia University Kearneysville Tree Fruit Research and Education Center will be closed in observance of Labor Day. 

September 13, 8:00 a.m. - noon. - Chemical Evaluation Field Day at WVU's Kearneysville Tree Fruit Research and Education Center. Pesticide Industry Representatives, Agricultural Research and Extension Personnel, Consultants and other interested persons are invited to tour research plots and obtain preliminary results from evaluations of acaricides, insecticides and fungicides on apples and peaches. For more information contact the WVU KTFREC at 304-876-6353.



2006 Fruit Grower Meeting Hosts 

Allenberg family - Allenberg Orchards
George & Susanne Behling - Nob Hill Orchards
Harvey Christie - Gourmet Central

Mary Frances Hockman & Gordon Hockman - Twin Ridge Orchards, Inc.
Orr family - George S. Orr & Sons

Garry & Kane Shanholtz - Shanholtz Orchards

2006 Fruit Grower Meeting Sponsors 

Adams County Nursery, Inc. - Phil Baugher
BASF - Gar Thomas
Bayer CropScience - Rick Love
CBC (America) Corp. - Greg Stamm
Chemtura - Ray Choban
Dow AgroSciences - Patti Schurr
Durand-Wayland, Inc. - Ron Shrum
Gowan Company - David Pieczarka
Helena Chemical Co. - Todd Metzger
Knouse Foods Coop., Inc. - Dave Cox
Syngenta Crop Protection, Inc. - Ryan Lins
UAP - Larry Dell
Winchester Equipment Co. - Doug Rinker


Tufted apple bud moth second generation egg hatch is estimated at 74% complete through August 20, based on an accumulation of 2771 degree days (DD) since biofix on May 3 at the WVU KTFREC. The stage of development through August 20 based on DD accumulations is the same as last year. Based on forecasted temperatures, second generation egg hatch is expected to reach completion about Aug. 26-27. For most effective control of late season larvae, recommended options include Intrepid, Rimon, Proclaim, SpinTor, and pyrethroids (Asana, Battalion, Baythroid, Danitol, Decis, Proaxis, Warrior). Orchards should be inspected over the next few weeks for larvae and/or injury. In addition to causing surface injuries, late season larvae that are not controlled are often found feeding in the calyx end of fruits, which can result in load rejection by processors. Larvae inside the calyx may also survive the dump tank and packing process of fresh fruit, and can result in rejection of fruit loads if found in packed fruit. 

Codling moth third generation egg hatch is estimated at 8% complete through August 20, based on an accumulation of 2292 DD since biofix on April 26. Insecticides should be applied for third generation control as soon as possible, if not already completed, in those orchards where the pheromone trap capture has exceeded 5 moths/trap/week. Recommended control options include  Azinphos-methyl (Guthion), Imidan, Assail, Calypso, Avaunt, Intrepid (12-16 oz/acre), Rimon, Cyd-X, Carpovirusine or pyrethroids (see above; considered less effective against codling moth than tufted apple bud moth).  Maintain spray intervals on a 2 week (complete) or 5-7 day (alternate-row-middle) schedule for as long as the trap threshold is exceeded. The percent of this generation that completes egg hatch, and the potential for late season fruit injury by larvae is dependent upon weather conditions. Not only do temperatures influence egg hatch and larval development, but also moth mating and egg-laying. Even though daytime temperatures may be warm enough for egg hatch and larval feeding, nighttime temperatures, especially in September, may be too cool for mating and egg-laying. 

Oriental fruit moth fourth generation eggs will be hatching during the remainder of this month and throughout September. In addition to populations that may already exist in apple orchards, third generation moths emerging in peach orchards will move to adjacent apple orchards because most peach fruits will have been harvested and shoots are no longer succulent for entry by larvae.  Therefore, be aware that an apple orchard with a low population up to this point, could experience late season fruit injury if adjacent to an infested peach orchard.

As with codling moth, the best approach for the remainder of the season is to monitor the male moth population with pheromone traps.  Initiate and maintain insecticide applications, as described for codling moth, in those blocks where the trap capture exceeds 10 moths/trap/week.  Recommended control options include the same materials as for codling moth (except for Cyd-X and Carpovirusine), plus sprayable pheromone (CheckMate OFM-F).  Orchards with a history of late season injury would be good candidates to receive sprayable pheromone during the last application of the season to provide 4-5 weeks of control (mating disruption).

Stink bugs have become an increasingly important pest complex causing late season injury to apples during the past 5 or so years.  Because injury resembles the physiological disorder cork spot, it has probably occurred at low levels and been misdiagnosed for quite a few years.  Reasons for the recent increase in injury are not completely understood, but changes in chemistries used for pest management (substitution of Intrepid and neonicotinoids for organophosphates and Lannate) and possible resistance are believed to be contributing factors. 

The stink bug complex attacking apple consists primarily of three species (brown, dusky, and green stink bugs) that cause most of the injury during August until harvest by puncturing maturing fruit.  Although the injury can be confused with cork spot, Dr. Mark Brown, USDA entomologist has found that it differs in three ways:  1) the edge of the depression on the fruit surface from stink bug feeding is gradual instead of abrupt as in cork spot; 2) the corky flesh is always immediately beneath the skin in stink bug injury, but may not be in contact with the skin in cork spot; and 3) a puncture is present from stink bug feeding that is visible with at least 40x magnification.

Orchards most likely to experience stink bug injury are those with poor weed control that are adjacent to woods and/or weedy borders.  Stink bugs are very difficult to manage because:  1) they are highly mobile; 2) have a broad host range, including many crops and broadleaf weeds; 3) move frequently between weed hosts and fruit trees; and 4) are therefore not continually exposed to insecticide residues for long periods of time.  Pyrethroids (see above) are likely to provide the most effective control, followed by Lannate and organophosphates (Guthion, Imidan).  Depending upon the situation, spraying the border rows adjacent to woods may provide sufficient control.  Improved weed management will also reduce stink bug injury.  For more information on stink bugs, consult the article in the upcoming July, August and September issue of The Mountaineer Grower.

 Brown stink bugDusky stink bugGreen stink bugStink bug fruit injuryStink bug fruit injuryStink bug fruit injury

Be sure to consider the preharvest interval (PHI) in Table 1 below when selecting management options for control of the above insects.

Table 1.  PHI for insecticides on apple.


PHI (days)

  Asana 21
  Assail 7
  Avaunt 14
  Azinphos-methyl (Guthion) 14a
  BT 0
  Battalion 21
  Baythroid 7
  Calypso 30
  Carpovirusine 0
  CheckMate OFM-F 0
  Clutch 7
  Cyd-X 0
  Danitol 14
  Decis 21
  Imidan 7
  Intrepid 14
  Lannate 14
  Proaxis 21
  Proclaim 14
  Rimon 14
  Sevin 3
  SpinTor, Entrust 7
  Warrior 21

a21 days if over 2 lbs/acre.


March 20 0
March 27 29 0 0
April 3 155 920 38
April 10 105 1600 39
April 17 90 2820 224 0
April 24 20 1064 239 2 0 0
May 1 14 293 224 7 5 0 2
May 8 4 120 85 47 40 0 35
May 15 1 57 29 20 34 7 25
May 22 0 15 29 23 37 1 4
May 30 0 384 25 11 29 0 23 0
June 5 36 1300 24 28 107 4 15 0
June 12 138 1120 19 14 48 10 6 0
June 19 155 1920 51 6 17 7 13 0
June 26 155 3200 92 0 4 6 3 3 0
July 3 61 2048 135 2 1 8 2 1 0
July 10 17 768 77 3 0 8 1 2 0
July 17 5 896 94 8 0 3 2 2 0
July 24 16 320 84 20 0 3 3 2 2
July 31 39 1984 114 9 7 5 3 2 1
August 7 77 1880 103 0 15 13 5 1 6
August 14 71 448 103 4 9 10 3 1 9
August 21 57 508 178 14 6 10 6 1 11

RBLR = Redbanded leafroller; STLM = Spotted tentiform leafminer; OFM = Oriental fruit moth; CM = Codling moth; TABM = Tufted apple bud moth; DWB = Dogwood borer; LPTB = Lesser peach tree borer; PTB = Peach tree borer; AM = Apple maggot.


Infection periods.  Current conditions: Drier than a saltine. At WVU-KTFREC, we have not recorded any significant wetting period since July 27 - 28 (see the list below). Our total rainfall for the month of August is 0.01 inches. Some scattered showers have occurred in the area and may have provided wetting conditions favorable for disease development at some locations.

Table 1. Dates and conditions for recent infection periods at the WVU - KTFREC, 2006.


Date 2006

Hours/ degrees F


July 4 - 5

16 hr/71 F


July 5 - 6

16 hr/66 F


July 9 - 10

13 hr/65 F


July 12-13

15 hr/72 F


July 18-19

14 hr/68 F


July 27-28

15 hr/71 F

Accumulated wetting hours.  As of August 21, 2006, we have accumulated 414 wetting hours. Accumulated wetting hours are useful for predicting the appearance of sooty blotch on nonsprayed fruit. Sooty blotch and fly speck were first observed at WVU-KTFREC on nonsprayed fruit during the week of July 10th.

Control failures with sooty blotch and flyspeck occur either because of poor spray coverage during the latter part of the growing season or because trees were left unprotected through more than 270 hr of accumulated wetting during the preharvest interval. Because fungicide protection on fruit is exhausted after 2 inches of rain, fungicide sprays may be needed in late August and September if heavy rains occur with more than 25 days remaining before fruit will be harvested. Twenty-five days is a "worst-case" scenario, based on experience, for accumulating 270 wetting hours.

See our "Current Conditions" Web page for details that are updated at least three times weekly.


Trade and brand names are used only for the purpose of information, and the West Virginia University Extension Service does not guarantee nor warrant the standard of the product, nor does it imply approval of the product to the exclusion of others which may also be suitable. The West Virginia University Extension service assumes no responsibility in the use of hazardous chemicals.

Individuals requesting an accommodation at a meeting because of a disability should contact one of the Extension Specialists at the WVU Kearneysville Tree Fruit Research and Education Center at 304-876-6353 at least five days prior to the event.

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PHONE:  304-876-6353
FAX:  304-876-6034
WEB:  www.caf.wvu.edu/kearneysville

The West Virginia University Cooperative Extension Service, U.S. Department of Agriculture, West Virginia County
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