August 6, 2007
|Upcoming Events||Pheromone Trap Counts||Plant Pathology|
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 presentation on apple maturity testing will be provided by Mark and Karen Burkhart. For more information contact the WVU KTFREC at 304-876-6353.
Tufted apple bud moth second generation egg hatch is estimated at 7% complete through August 5, based on an accumulation of 2258 degree days (DD) since biofix of first brood moths on May 11 at the WVU KTFREC. Development is about 3 days behind last year based on DD accumulations through August 5. This week is the ideal time to initiate applications of Intrepid, Rimon, SpinTor, Proclaim, or Lannate plus an organophosphate [Azinphos-methyl (Guthion), Imidan] insecticide. See the July 23rd issue of this newsletter for more information on materials and application timing for second generation control.
Codling moth second generation egg hatch is estimated to be 89% complete through August 5, based on an accumulation of 1903 DD since biofix of first brood moths on May 5. Third generation egg hatch is predicted to begin on August 13-16. Insecticides should be applied for third generation control in those orchards where the pheromone trap capture exceeds 5 moths/trap/week. Spray timing for control, based on DD accumulations after biofix, depends on the material selected. If using Rimon, Intrepid, Assail, Calypso, Cyd-X or Carpovirusine, initiate control at 2160 DD after biofix (1% egg hatch, estimated on August 13-16). If using Avaunt, Azinphos-methyl (Guthion), Imidan or pyrethroids, initiate control at 2270 DD after biofix (6% egg hatch, estimated on August 17-21). An initial spray of any material should be followed by a second complete application in about 10-14 days (7-10 days for Cyd-X or Carpovirusine), or up to three additional alternate-row-middle applications 5-7 days apart (3-5 days apart for Cyd-X or Carpovirusine), if needed based on pheromone trap capture, proximity to harvest, and warm temperatures that favor continued mating and egg-laying.
Oriental fruit moth third generation egg hatch is estimated at 66% complete on peach, based on an accumulation of 2578 DD since biofix on April 21. Egg hatch is most likely lagging behind a little on apple due to slower development on this fruit crop. It is important to remember that third generation adults that emerge in peach orchards will fly to adjacent apple orchards to deposit fourth generation eggs if peach fruits have been harvested. Therefore, an apple orchard that is clean at this point could sustain late season fruit injury if adjacent to an infested peach orchard. Because there is typically overlap between the third and fourth generations, the best policy for the remainder of the season is to base the need for treatment on pheromone trap capture. Initiate insecticide applications about 7 days after exceeding a trap threshold of 10 moths/trap/week, and maintain spray intervals on a 2 week (complete) or 5-7 day (alternate-row-middle) schedule for as long as this condition continues. Control options on peach [days to harvest] include Imidan , Ambush , Asana , Pounce , Proaxis , Warrior , Intrepid , Baythroid (7), Lannate , and carbaryl (Sevin) . Control options on apple include Calypso , Asana , Battalion , Decis , Proaxis , Warrior , Azinphos-methyl (Guthion) , Intrepid , Avaunt , Danitol , Rimon [14}, Assail , Baythroid , and Imidan . In addition, CheckMate OFM-F sprayable pheromone  may be applied on both apple and peach to provide up to 4 weeks of adult control through mating disruption.
White apple leafhopper second generation nymphs will soon begin to appear on the undersides of apple leaves. These may be accompanied by third generation (second generation on apple) nymphs of rose leafhopper in some orchards. Young nymphs of both leafhopper species appear identical, but older nymphs of rose leafhopper can be differentiated by their spotted appearance (black spots on the back). Nymphs of both species will reach the adult stage during the harvest period and, if abundant, can become a nuisance to pickers. In addition, excretion of honeydew from high populations can result in sooty mold deposits on fruit. Examine the undersides of 10 older leaves per tree on 5-10 trees per block and determine the average number of nymphs per leaf (both species combined). To prevent economic impact from leafhopper feeding, an average of 3 nymphs per leaf is recommended as an action threshold. An average of 1 nymph per leaf is recommended as an action threshold where the nuisance to pickers from adults is a concern during harvest. Recommended materials for control include Lannate, Vydate, Provado, Actara, Assail, Calypso, Clutch, and Avaunt.
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.
PHEROMONE TRAP COUNTS
WEST VIRGINIA UNIVERSITY KTFREC
|DATE - 2007||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.
Infection periods. We recorded three new infection periods since the last Orchard Monitor on July 23 (Table 1). Rainfall totals for July were about 2 inches below normal in most locations in the Eastern Panhandle, according to our weather stations. Rainfall for June was about 1 inch below normal, for May about 2.5 inches below normal, and April about 1 inch below normal. In the two-week period from July 23 through August 6, we accumulated 76 additional wetting hours for a total of 327 (AWH = 447 last year at this time). Normal rainfall (65-year average) for August is about 3.9 inches.
Control failures with sooty blotch and flyspeck on apple 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. Maintaining fungicide coverage at normal, extended intervals will protect apple fruit from summer diseases as long as we remain in the dry weather pattern we've been experiencing so far this season.
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|
|19.||July 27-28||12 hr/68° F|
|20.||July 28-29||15 hr/69° F|
|21.||August 5-6||18 hr/71° 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
TREE FRUIT RESEARCH AND EDUCATION CENTER
P. O. BOX 609
KEARNEYSVILLE, WV 25430-0609
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