WVU Extension Service: The Orchard Monitor: Committed to the Integration of Orchard Management Practices
June 25, 2007

Upcoming Events


Pheromone Trap Counts Plant Pathology



June 28, 6:00 p.m. – Tree Fruit Grower Twilight Dinner and Meeting at Levels Fire Hall, Levels, W. Va. Following dinner, seasonal updates will be provided by WVU Extension Specialists, and a peach orchard tour which will include a deer fence and irrigation system will be provided by hosts Garry and Kane Shanholtz. For more information contact the Hampshire County Extension Office at 304-822-5013. 

July 10, 6:00 p.m. – Tree Fruit Grower Twilight Dinner and Meeting at Ridgefield Farm and Orchard, Harpers Ferry, W. Va. To reach the orchard, take Flowing Springs Road (Route 17) from Shepherdstown for 2 miles to Route 230. Travel 3 miles on Route 230 to crossroad (Kidwiler Road) and turn left. Orchard is 0.4 mile on right. The agenda will include dinner sponsored by various orchard support industries, seasonal updates by WVU Extension Specialists, and a tour by hosts Alan Gibson and Scott Beard. For more information, contact the WVU-KTFREC at 304-876-6353 or by e-mail at Libby.Nester@mail.wvu.edu

July 12, 8:45 a.m. – 12:40 p.m. – Maryland Summer Tour sponsored by the Maryland State Horticultural Society and Maryland Cooperative Extension. Participants will meet at Sandoe’s Fruit Market and carpool to the Round Barn Farm Market and Hollabaugh Brothers Fruit Farms and Market, concluding back at Sandoe’s Fruit Market for lunch. Registration of  $10 is due by July 5. For a registration form, contact the WVU-KTFREC at 304-876-6353 or by e-mail at Libby.Nester@mail.wvu.edu. For more information, contact Cindy Mason at 301-432-2767 ext. 301.

July 12, 12:00-6:30 p.m. – Grower Field Day at The Pennsylvania State University Fruit Research and Extension Center, Biglerville, PA. Concurrent research and educational sessions will be held throughout the afternoon, which will include tours of facilities and research field plots. Topics will include presentations on newest directions in orchard establishment and maintenance, biorational and alternative methods of controlling insect pests, diseases and weeds, as well as updates on organic apple production and vineyard establishment. Registration of $15 (includes dinner and educational packets) is due by June 30. For a registration form, contact the WVU-KTFREC at 304-876-6353 or by e-mail at Libby.Nester@mail.wvu.edu. For more information, contact Karen Weaver at 717-677-6116 ext. 0.


Oriental fruit moth second generation egg hatch continues and is estimated at 39% complete through June 24, based on an accumulation of 1322 degree days (DD) since biofix on April 21 at the WVU KTFREC. For control options, refer to the June 11th issue of this newsletter.

Codling moth first generation egg hatch is almost complete (estimated at 97%) based on an accumulation of 865 DD since biofix (May 5) through June 24 at the WVU KTFREC.  Apple orchards should be inspected at this time for first generation larval injury to fruit in order to evaluate the effectiveness of management programs.  Fruit injury is more likely to occur in the upper parts of apple trees since more moth mating and egg-laying occurs in this area, and spray coverage is likely to be weakest in this portion of the tree.  Larvae may enter fruit from either the side or calyx end, resulting in the presence of frass (excrement, see photo) on the surface where tunneling has been successful.  First generation larvae usually have greater success entering the calyx end because the side of the apple is harder early in the season.  Injury also may be expressed as “stings”, which consist of small shallow holes resulting from the death of young larvae that have been poisoned after puncturing the apple skin.  The absence or size of larvae (1/2-5/8 inch long when mature in 3-4 weeks) found in injured fruit can indicate when the control failure occurred during the egg hatching period.  The absence of a larva and the presence of an exit hole in apples with frass indicates that the larva has already matured and left the apple, having entered the apple early in the egg-hatching period (latter part of May).  The presence of larger larvae in fruit indicates a control weakness during the first half of the egg-hatching period (early June), whereas smaller larvae indicate inadequate control during the second half of the egg-hatching period (mid June and later).  Knowledge of larval size in injured fruit, when coupled with pesticide record information can increase understanding of management failures and lead to improved control against future generations. 

The second moth flight is expected to begin within a week.  In order to prevent fruit injury, control of the second generation should be implemented in those orchards where the pheromone trap capture exceeds 5 moths per trap per week.  In order to delay the development of resistance, materials selected for control of the second generation should be from a different chemical class (different mode of action) than was used against the first generation (see page 39 of the 2007 Spray Bulletin for a listing of chemicals by class).  Recommended options include Rimon at 1050-1150 DD (0-2% egg hatch); Intrepid, Esteem, Assail, Calypso, or CM granulosis virus (Cyd-X, Carpovirusine) at 1150 DD (2% egg hatch); or Avaunt, Azinphos-methyl (Guthion) or Imidan at 1250 DD after biofix (6% egg hatch).  An initial spray should be followed by a second complete application in about 10-14 days (300 DD), or three additional alternate-row-middle applications 5-7 days apart.  Complete sprays of Cyd-X or Carpovirusine should be repeated every 7-10 days for a total of 3-4 applications. Based on DD accumulations since biofix, development on this date is only one day ahead of last year.

Codling moth fruit injury
Japanese beetle adults and leaf injury on apple

Japanese beetle adults are expected to begin emerging very soon, most likely following a rain event this week.  The most important threat from this insect is to dwarf and non-bearing apple trees and to stone fruits near and during harvest.  Feeding injury on apple leaves results in a “lace-like” appearance as beetles consume the leaf tissue between the veins.  Injury to apple fruits is not common and usually only occurs on mature fruits that have already been damaged by some other factor.  Sevin is considered the most effective control option, with the XLR Plus formulation considered to be less disruptive to mite predators than other formulations.  Other options include Lannate, Assail and Surround.  Surround is most effective if application begins before beetles begin feeding on trees.

Japanese beetles feeding in apple
Apple maggot adult

Apple maggot (AM) poses a threat to commercial apple orchards in West Virginia that are adjacent to abandoned orchards or wild hosts.    Fly emergence, which typically begins after mid-June, should be monitored in all commercial apple orchards that are adjacent to these sites.  Yellow pre-baited panel traps or red sphere traps should be installed on the outside row closest to the wild hosts or abandoned orchard.  Position traps about 5-6 ft above the ground so they are surrounded, but not touched or obstructed from view, by fruit and leaves.  Traps should be inspected and AM flies counted weekly.  When using the yellow trap, an insecticide [azinphos-methyl (Guthion), Imidan, Diazinon, Assail, Calypso, or Avaunt] should be applied within 7-10 days of catching a single fly.  With the red sphere trap baited with apple volatiles, apply one of these insecticides immediately if an average of 5 or more flies per trap are caught within a week.  If no apple volatiles are used with the red sphere trap, the threshold should be lowered to 1 fly per trap.  Capture of flies for 1-14 days following the insecticide application can be discounted.  Once 14 days have elapsed since the last application, retreat immediately if the threshold is reached again.

Yellow panel trap
Red sphere trap


March 19 0
March 26 2 0
April 2 121 3 0
April 9 54 28 1
April 16 23 93 0
April 23 18 640 68
April 30 22 1220 230 0 0
May 7 6 396 404 3 0 0 0
May 14 1 132 120 33 2 0 33
May 21 0 12 74 17 17 0 23
May 29 0 64 22 22 43 4 30 0
June 4 3 1280 4 17 12 3 15 1
June 11 59 1472 12 5 0 8 12 0
June 18 50 960 33 1 0 1 7 2 0
June 25 50 2656 69 0 3 0 4 1 0

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. We recorded four new infection periods since the last Orchard Monitor on June 11. Please refer to the table below for details. Rainfall totals this month range from about 1.4 to 2.7 inches in various locations in the Eastern Panhandle, according to our weather stations (2.5 inches at WVU-KTFREC). The 65-year average rainfall for June is 3.4 inches. So far we have avoided the long infection periods (48 to 72 hours) that are often accompanied by fungicide residue removal and poor spraying conditions.

Table 1. Dates and conditions for infection periods at the WVU - KTFREC, 2007.


Date 2007

Hours/ degrees F


June 1-2

14 hr/65 F


June 3-4

24 hr/65 F


June 12-13

18 hr/63 F


June 13-14

21 hr/60 F


June 19-20

11 hr/69 F


June 21-22

11 hr/63 F

Accumulated wetting hours.  As of June 25, 2007, we have accumulated 177 wetting hours from a petal fall date of May 4 (last year at this time AWH = 206). 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.

Brown rot.  Incidence of brown rot fruit infection is proportional to temperature and wetness duration. Optimum temperature range is 72-77 F for infection of peach fruit and infection can occur following only 3 hr of wetness at high inoculum concentrations. Longer wet periods during infection result in shorter incubation periods. Insects (nitidulid beetles and honeybees) also can be important as vectors of the brown rot fungus during fruit ripening, carrying conidia to injury sites produced by oriental fruit moth, Japanese beetle, green June beetle, stink bugs, and other insects, or birds, that injure fruit. Wounded fruit are infected much more readily than nonwounded fruit. Hail damage near harvest can lead to a devastating brown rot problem. At harvest, apparently healthy fruit usually are contaminated with spores or latent infections that, under favorable conditions, may later produce decay during storage and marketing.

Effective control of brown rot depends on attention to orchard sanitation; proper pruning of trees to facilitate drying and penetration of spray materials; monitoring for disease every 3 to 5 days during the preharvest period, being aware of favorable weather and the potential for bird, insect and hail damage; and use of effective fungicides at 7 to 10 day intervals during the preharvest and harvest periods. See the 2007 Spray Bulletin for suggested chemicals and rates of application. The sterol-inhibiting fungicides, Orbit, Elite, and Indar, are the best fungicides for controlling the disease and show generally similar performance in preharvest assessments. Fruit treated with Indar right before harvest generally shows less rot in the postharvest environment. Recent data from studies in Virginia, New Jersey, and California show that the recently-registered reduced-risk fungicides Pristine and Elevate are very good to excellent for managing pre- and post-harvest brown rot. Reduced-risk fungicides have a low impact on the environment, high specificity to target organisms, low potential for groundwater contamination, and low potential for human health risks. Pristine is registered for use on all stone fruits, whereas Elevate is limited to use on peaches, nectarines and cherries.

Alternation of the sterol-inhibiting fungicides with Pristine or Elevate may help reduce the risk of the brown rot fungus becoming resistant to the SI’s. If fruit are washed during the packing operation, the efficacy of Pristine and Elevate for preventing wound infections is likely to be reduced relative to the sterol-inhibiting fungicides. For this reason, in years when the risk of brown rot is high or if packing conditions are unsanitary, the use an SI fungicide right before harvest is recommended.

Scholar (fludioxonil), another reduced-risk material, is available for postharvest use on all pome and stone fruits (excluding cherries). Data show that infections of wounds that occur in the field at harvest are effectively stopped by post-harvest treatments with Scholar, which is typically done on the same day that fruit are harvested. Including Scholar as a postharvest treatment may be useful in years when inoculum pressure is high, conditions at harvest are favorable for brown rot infection, or packinghouse conditions are unsanitary. Scholar is stable in 100 ppm chlorine.

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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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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