WVU Extension Service: The Orchard Monitor: Committed to the Integration of Orchard Management Practices
July 24, 2006

Upcoming Events


Pheromone Trap Counts Plant Pathology



August 1, 6:00 p.m. - Tree Fruit Grower Twilight Dinner and Meeting at Twin Ridge Orchards, Inc., Shenandoah Junction, W. Va.  To reach the orchard, travel approximately 3 miles from Kearneysville on Rt. 480 to Rt. 16 (Ridge Road) on the right.  Travel Ridge Road for 3 miles to the barn on the right.  Following dinner, seasonal updates will be provided by Extension Specialists from the WVU KTFREC, and a tour will be conducted by Mary Frances Hockman and Gordon Hockman.  For more information contact the WVU KTFREC at 304-876-6353.


Pesticide update.  The U.S. Environmental Protection Agency (EPA) has proposed changes to the Imidan label for apples, peaches and nectarines.  The specific proposed changes include:  1) increasing the restricted-entry interval (REI) from 3 to 7 days; 2) requiring buffer zones around houses and occupied dwellings; 3) eliminating use in "pick your own" operations; and 4) eliminating aerial applications.  You are encouraged to submit your comments to EPA on the impact of these proposed changes by the deadline of August 8.  Comments must include the docket identification number (EPA-HQ-OPP-2002-0354), and may be submitted on-line at www.regulations.gov (follow on-line instructions), or by mail to Office of Pesticide Programs, Regulatory Public Docket (7502P), Environmental Protection Agency, 1200 Pennsylvania Ave., NW, Washington, DC 20460-0001.  Alternatively, individual and organization comments may be sent by mail or e-mail to James Cranney, U.S. Apple Association, 8233 Old Courthouse Road, Vienna, VA 22182, jcranney@usapple.org by August 4 for collective submission to the docket. 

Codling moth hatch of second generation eggs continues and is estimated at 49% complete through July 23, based on an accumulation of 1576 degree days (DD) since biofix of first brood moths on April 26 at the WVU KTFREC.  A second insecticide application is recommended approximately 2 weeks (300-400 DD) after the initial application in those orchards where the pheromone trap capture has exceeded 5 moths/trap/week.  Options include Rimon, Intrepid, Esteem, Assail, Calypso, CM granulosis virus (Cyd-X, Carpovirusine), Avaunt, Azinphos-methyl (Guthion) or Imidan.

Oriental fruit moth hatch of third generation continues and is estimated at 27% complete through July 23, based on an accumulation of 2281 DD since biofix of first brood moths on March 31 at the WVU KTFREC.  Refer to the July 10 issue of The Orchard Monitor newsletter for control options and timing in those apple and peach orchards where the pheromone trap capture has exceeded 10 moths/trap/week.

Tufted apple bud moth adult emergence (second flight) is expected to begin this week.  This would be a good time to assess fruit injury from first brood larvae to aid in developing the specific program needed for second brood control.  In orchards with very little, if any, fruit injury and low second flight trap captures, a combination of Lannate plus organophosphate [Azinphos-methyl (Guthion) or Imidan] would probably provide sufficient control of second brood larvae.  Higher levels of fruit injury and/or trap captures would require one or more applications of Intrepid, Rimon or SpinTor to minimize second brood fruit injury.

All materials will perform best if spray applications are timed to coincide with egg hatch based on degree day accumulations.  For organophosphate + Lannate combinations, make two complete applications at 2280-2355 DD (10-20% egg hatch) and 2665-2740 DD (60-70% egg hatch), or four alternate-row-middle applications at 7-day intervals, beginning at 2210-2245 DD (1-5% egg hatch).  For Intrepid, Rimon or SpinTor, make an initial complete application at 2355-2435 DD (20-30% egg hatch), and then again at 2665-2740 DD (60-70% egg hatch) where pest pressure is high.  If alternate-row-middle application of these materials is planned, begin at 2280 DD (10% egg hatch) and repeat at 7-day intervals for up to four applications, depending upon pest pressure.  Through July 23, 1905 DD have accumulated since biofix of first brood moths on May 3 at the WVU KTFREC.  Based on forecasted temperatures, second brood egg hatch is predicted to begin on July 31 to August 2.

San Jose scale fruit injury

San Jose scale second generation crawler emergence should be monitored over the next 4-5 weeks in those blocks in which greater than 1% of the fruit was injured at harvest last season.  Monitor crawler emergence by wrapping black electrician's tape (sticky side out) around tree limbs that are encrusted with dark scale coverings.  A thin film of petroleum jelly may be spread on the tape surface to enhance crawler capture.  An alternative approach is to cover the black electrician's tape (wrapped with sticky side against the branch) with double sided cellophane tape.  Inspect the tape traps twice weekly for the bright yellow crawlers, and apply Esteem, Centaur, Diazinon or Provado as a high volume spray when emergence is first detected and again in 10-14 days.  Adequate coverage of the tops of trees is critical to control of this insect.

San Jose scale tape trap


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

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.  At WVU-KTFREC, we recorded two significant wetting periods since the last newsletter on July 10th (see the list below). Our total rainfall for the month of July as of Monday morning July 24 is 1.61 inches at WVU-KTFREC.

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

No. Date 2006 Hours/degrees F
16. July 4 - 5 16 hr/71 F
17. July 5 - 6 16 hr/66 F
18. July 9 - 10 13 hr/65 F
19. July 12 - 13 15 hr/72 F
20. July 18 - 19 14 hr/68 F

Accumulated wetting hours.  As of July 10, 2006, we had accumulated 357 wetting hours, for petal fall date of April 27. Sooty blotch and fly speck were first observed on nonsprayed fruit during the week of July 10th. As of July 24, we have accumulated 390 wetting hours.  Accumulated wetting hours are useful for predicting the appearance of sooty blotch on nonsprayed fruit. Symptom development for these diseases is highly dependent upon temperature and moisture conditions surrounding the fruit. The appearance of sooty blotch symptoms has been predicted with reasonable accuracy by using accumulated wetting hours (AWH). Visible signs of sooty blotch may appear following approximately 260 ‑ 300 AWH (earlier in the season (260 AWH) if the disease was severe last year, later in the season (300 AWH) if not). The AWH threshold for making the decision to include Topsin-M in the spray program is 225 for high disease pressure and 275 for low disease pressure. Each of these threshold values presumes that 25 additional AWH will occur in the next 5 days after reaching the threshold.

USDA laboratory confirms plum pox virus in New York.  WASHINGTON, July 17, 2006--The U.S. Department of Agriculture's National Plant Germplasm and Biotechnology Laboratory in Beltsville, Md., today confirmed the presence of the plum pox virus (PPV) on plum tree leaf samples collected by New York State Department of Agriculture and Markets (NYSDAM) officials.

As part of a seven-year survey for the virus, state and federal agriculture officials collected 22 leaf samples from a 108-tree orchard located in Niagara County, N.Y.--within five miles of plum pox eradication zones in Canada. The samples were sent to Cornell University's diagnostic laboratory for testing, where researchers obtained positive results. The virus was first detected in Canada back in 2000. The plum pox strain identified in New York is identical to the D strain of the virus found in both Canada and Pennsylvania. The D strain of the virus is less virulent than other strains, making it easier to contain.

NYSDAM's early discovery of PPV is credited to the department's active surveys for plant pests and diseases. Survey specialists are currently surveying a 5-mile radius surrounding the initial detection to determine the extent of infestation. USDA will establish a cooperative eradication program with the state of New York. The program will include conducting extensive detection and delimiting surveys, establishing quarantine areas where infestations are found, and the removal of infested orchards and other host material within a buffer area of any infestation.

Plum Pox is a viral disease of stone fruit species that first appeared in the United States in Pennsylvania in October 1999. The plant virus does not pose any human health risks. Since the discovery, agriculture officials there have successfully contained its spread. New York is only the second state where plum pox has been detected. PPV is the cause of a serious plant disease, affecting a number of species, including peach, nectarine, apricot and plum. Several aphid species can serve as carriers of the virus. The virus stays viable in the aphid's mouthparts for a period of approximately one hour and most aphids can generally transmit infection several hundred meters from the initial source plant. The finding of plum pox will not hinder the production or harvest of stone fruit in Niagara County this year.


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

P. O. BOX 609
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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