WVU Extension Service: The Orchard Monitor: Committed to the Integration of Orchard Management Practices
July 23, 2007

Upcoming Events

Entomology

Pheromone Trap Counts Plant Pathology

 

UPCOMING EVENTS

August 14, 6:00 p.m. – Tree Fruit Grower Twilight Dinner and Meeting at Knouse Foods Cooperative, Inc., Inwood, W. Va. Following dinner, seasonal updates will be provided by Extension Specialists from the WVU KTFREC, and a tour of the processing plant will be provided. For more information contact the WVU KTFREC at 304-876-6353.

ENTOMOLOGY

Oriental fruit moth hatch of third generation eggs has begun and is estimated at 14% complete through July 22, based on an accumulation of 2137 degree days (DD) since biofix on April 21 at the WVU KTFREC. Development on this date is about 3 days later than last year. The third generation poses a threat to peach and nectarine fruits near or during harvest.  Larvae can enter anywhere on the fruit, resulting in the exudation of gum and frass (excrement) from the wound area.  As the gum ages, a sooty mold may form on it, turning the entire wound area black.  Larvae can also enter the fruit through the inside of the stem, and therefore leave no evidence of entry except for a small mark at the stem end of the picked fruit. 

Control of the third generation is justified where the pheromone trap capture exceeds 10 moths/trap/week in both peach and apple.  In peach and nectarine, apply either Imidan, Lannate or Carbaryl (Sevin) at 2100-2200 DD (11-19% egg hatch, occurring now).  A second application may be needed in about 2 weeks (300-350 DD), depending upon pest pressure and proximity to harvest.   Be sure to consider the following days to harvest limitations when selecting materials for application in peach and nectarine:  Imidan [14], Lannate [4 on peach, 1 on nectarine], and carbaryl (Sevin) [3]. 

As a general guideline in apple, apply Rimon at 2300-2350 DD (29-36% egg hatch, estimated on July 28-30); or Assail, Calypso or Intrepid at 2350-2400 DD (36-42% egg hatch, estimated on July 30 to August 1); or Avaunt, azinphosmethyl (Guthion) or Imidan at 2450-2500 DD (49-56% egg hatch, estimated on August 2-4).  A second application may be needed in about 2 weeks (450-500 DD), depending upon pest pressure.  Since the egg hatch model is based on development on peach (which is faster), actual egg hatch on apple often falls behind DD based predictions by this time of the season. Therefore, in apple, it is best to treat within 7-10 days of exceeding the above trap threshold and to maintain spray intervals on a 2 week (complete) or 5-7 day (alternate-row-middle) schedule for as long as this condition continues.  Sprayable pheromone (CheckMate OFM-F) is also an option that can be targeted against adults to provide mating disruption in apple, peach and nectarine.  Pheromone traps should be used to monitor performance and schedule applications, which provide about 4 weeks of control.

Oriental fruit moth fruit injury
Brown stink bug on peach

Stink bugs can pose a threat to peach and nectarine near harvest. Feeding on fruit often results in the exudation of gum in droplets or strings. Although this injury is usually of no direct consequence, it does provide a wound for the entry of brown rot that can result in significant losses under favorable environmental conditions. Occasionally, late season feeding may be expressed as darker green “water-soaked” areas on the fruit surface, which can result in downgrading. A third type of injury is often not evident until harvested fruit are brought out of storage, which consists of small, tan-colored, surface depressions with internal tissue breakdown. This injury can result in losses after fruit are shipped for sale. 

Pyrethroid insecticides, followed by Lannate, are considered the most effective control options to prevent this late season injury, and will also provide control of oriental fruit moth. The following days to harvest limitations should be considered when selecting these materials for stink bug management: Ambush [14], Asana [14], Pounce [14], Proaxis [14], Warrior [14], Baythroid [7], and Lannate [4 on peach, 1 on nectarine]. These materials, especially pyrethroids, may result in an increased mite population during harvest, and/or a higher incidence of overwintering mite eggs.

Gummosis and water-soaked injuries on peach

Codling moth hatch of second generation eggs continues and is estimated at 42% complete through July 22, based on an accumulation of 1536 DD since biofix of first brood moths on May 5 at the WVU KTFREC.  A second complete insecticide application approximately 2 weeks (300-400 DD) after the initial application, or up to four alternate-row-middle applications, 5-7 days apart, are recommended in those orchards where the pheromone trap capture has exceeded 5 moths/trap/week.  Options include azinphosmethyl (Guthion), Imidan, Rimon, Intrepid, Esteem, Assail, Calypso, or Avaunt. CM granulosis virus (Cyd-X, Carpovirusine) is only recommended as a complete spray every 7-10 days for a total of 3-4 applications. 

Tufted apple bud moth adult emergence (second flight) has just begun.  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 [azinphosmethyl (Guthion) or Imidan], or BT 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, SpinTor, or Proclaim 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, or BT, 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 DD (1% egg hatch).  For Intrepid, Rimon, SpinTor, or Proclaim 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 22, 1817 DD have accumulated since biofix of first brood moths on May 11 at the WVU KTFREC.  Based on forecasted temperatures, second brood egg hatch is predicted to begin on August 4-6.

PHEROMONE TRAP COUNTS
WEST VIRGINIA UNIVERSITY KTFREC

DATE - 2007 RBLR STLM OFM CM TABM DWB LPTB PTB AM
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
July 2 36 1664 62 0 0 3 4 1 0
July 9 23 640 113 22 0 2 2 1 0
July 16 12 1120 89 1 0 2 1 5 1
July 23 20 1760 49 29 3 3 0 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.

PLANT PATHOLOGY

Infection periods.  We recorded no new infection periods since the last Orchard Monitor on July 9.  Rainfall totals for July are about 0.4 inches in most locations in the Eastern Panhandle, according to our weather stations. The 65-year average rainfall for July is 3.7 inches. In the two-week period from July 9 through July 23, we have accumulated 6 additional wetting hours for a total of 239 (AWH = 406 last year at this time).

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

No. Date 2007 Hours/ degrees F
9. June 1-2 14 hr/65 F
10. June 3-4 24 hr/65 F
11. June 12-13 18 hr/63 F
12. June 13-14 21 hr/60 F
13. June 19-20 11 hr/69 F
14. June 21-22 11 hr/63 F
15. June 27-28 12 hr/70 F
16. June 28-29 16 hr/69 F
17. July 4-5 14 hr/70 F
18. July 5-6 14 hr/ 66 F

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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