WVU Extension Service: The Orchard Monitor: Committed to the Integration of Orchard Management Practices
August 29, 2005

Upcoming Events Meeting Hosts
and Sponsors

Entomology

Pheromone Trap Counts Plant Pathology

 

UPCOMING EVENTS

September 5. - The West Virginia University Kearneysville Tree Fruit Research and Education Center will be closed in observance of Labor Day. 

September 14, 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.

MEETING HOSTS & SPONSORS

THANK YOU! 

2005 Fruit Grower Meeting Hosts 

Bruce Barr - Barr Orchards
Bill & Todd Butler - Butler's Orchard
Harvey Christie - Gourmet Central
Eli Cook - Spring Valley Farm and Orchard
David Cosby - National Fruit Products Co., Inc.
Ron Slonaker - Jefferson Orchards 

2005 Fruit Grower Meeting Sponsors 

Adams County Nursery, Inc. - Phil Baugher
BASF - Gar Thomas
Bayer CropScience - Rick Love
CBC (America) Corp. - Greg Stamm
Cerexagri - John Miller
Dupont Company - John R. Clawson
Durand-Wayland, Inc. - Ron Shrum
Gowan Company - David Pieczarka
Green, Inc. - Elizabeth White
Helena Company - Todd Metzger
Knouse Foods Coop., Inc. - Dave Cox
National Fruit Product Co., Inc. - Jim Robinson
UAP - Larry Dell
Uniroyal Chem./Crompton Co. - Ray Choban

Winchester Equipment Co. - Doug Rinker


ENTOMOLOGY

Tufted apple bud moth second generation egg hatch is estimated at 100% complete through August 28th, based on an accumulation of 2986 degree days (DD) since biofix on May 8.  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 20% complete through August 28th, based on an accumulation of 2437 DD since biofix on May 6th.  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 options include  Azinphos-methyl (Guthion), Imidan, Assail, Calypso, Clutch, Intrepid (higher rate), Rimon, Cyd-X, Carpovirusine or pyrethroids (Asana, Danitol, Proaxis, Warrior).  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 later in September, may be too cool for mating and egg-laying.

Oriental fruit moth fourth generation eggs will be hatching 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 application, 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 (MEC-OFM or 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 4-5 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 Confirm, Intrepid and neonicotinoids for Penncap-M and other organophosphates) 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.

Dr. Brown also found that apple cultivars differ in susceptibility to stink bug injury.  Of 31 cultivars that were evaluated, the highest levels of injury occurred on 'Braeburn', 'Jonica', 'Jonagold', 'Starkspur Dixiered', 'Granny Smith' and 'Stayman Winesap'. 

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 they:  1) 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 (Asana, Danitol, Proaxis, Warrior) are likely to provide the most effective control, followed by organophosphates (Guthion, Imidan) and Lannate.  Depending upon the situation, spraying the border rows of orchards adjacent to woods may provide sufficient control.  Improved broadleaf weed management will also reduce stink bug injury.

Brown stink bug Dusky stink bugGreen stink bugStink 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.

Insecticide

PHI (days)

Asana

21

Assail

7

Avaunt

14

Azinphos-methyl
(Guthion)

14a

BT

0

Calypso

30

Carpovirusine

0

CheckMate OFM-F

0

Clutch

7

Cyd-X

0

Danitol

14

Imidan

7

Intrepid

14

Lannate

14

MEC-OFM

0

Proaxis

21

Sevin

3

SpinTor, Entrust

7

Warrior

21

a21 days if over 2 lbs/acre.

PHEROMONE TRAP COUNTS
WEST VIRGINIA UNIVERSITY KTFREC

DATE - 2005 RBLR STLM OFM CM TABM DWB LPTB PTB AM
March 21 0            
March 28 3 0            
April 4 17 9 0            
April 11 73 720 3            
April 18 51 896 42            
April 25 34 1372 186            
May 2 7 256 89 0 0 0 0    
May 9 8 140 53 15 7 0 0    
May 16 5 94 163 32 76 0 18    
May 23 2 15 23 21 131 1 24    
May 31 0 0 5 4 108 2 14 0  
June 6 0 52 10 9 144 1 14 0  
June 13 34 1280 9 23 132 0 37 3  
June 20 121 704 6 7 50 17 28 0  
June 27 135 1728 14 1 9 13 13 3 0
July 5 122 1312 30 8 1 15 11 2 0
July 11 34 640 7 13 2 14 4 0 1
July 18 17 1280 9 17 1 8 2 0 4
July 25 12 416 9 36 2 25 1 0 2
August 1 15 463 39 20 8 15 4 0 4
August 8 44 1280 33 12 13 18 3 0 2
August 15 77 480 55 5 32 13 3 1 1
August 22 178 440 73 7 51 22 15 3 2
August 29 143 640 67 4 43 12 12 1 1
DATE - 2005 RBLR STLM OFM CM TABM DWB LPTB PTB AM

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.

PLANT PATHOLOGY

Infection periods.  We recorded two rain events since the last Orchard Monitor was published on August 15th. Other rain events have occurred in other locations, so your records may differ from those presented below. Total rainfall in the past two weeks has been 0.71 inches and for the past four weeks, 1.35 inches. 

 Table 2. Dates and conditions for summer infection periods at the WVU - KTFREC, 2005.

No. Date 2005 Hours/ degrees F
10. June 9 - 10 13 hr/70 F
11. July 5 - 6 18 hr/68 F
12. July 8 18 hr/66 F
13. July 13 - 14 15 hr/71 F
14. July 15 7 hr/72 F
15. July 16 10 hr/74 F
16. July 16 - 17 14 hr/74 F
17. July 25 6 hr/72 F
18. Aug. 7 - 8 19 hr/69 F
19. Aug. 9 14 hr/ 70 F
20. Aug. 19 9 hr/ 69 F
21. Aug. 26 - 28 37 hr/ 66 F

Accumulated wetting hours.  Threshold warning - threshold exceeded: As of August 29, 2005, we have accumulated 399 to 445 wetting hours, for petal fall dates of May 14 and May 7, respectively. Signs of flyspeck were first observed on July 20th at WVU - KTFREC (between 244 to 290 AWH depending on whether accumulations began on May 14 or May 7, respectively).

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.


READ THE LABEL CAREFULLY AND USE THE CHEMICALS IN ACCORDANCE WITH LABEL CAUTIONS, WARNING AND DIRECTIONS. REQUEST A MATERIAL SAFETY DATA SHEET (MSDS) FROM THE MANUFACTURER FOR EACH PRODUCT YOU USE.

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.


Helping you put knowledge to work


WEST VIRGINIA UNIVERSITY
TREE FRUIT RESEARCH AND EDUCATION CENTER
P. O. BOX 609
KEARNEYSVILLE, WV 25430-0609
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
Boards of Education and County Commissions Cooperating.  Equal Opportunity / Affirmative Action Institution


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