August 7, 2006

PESTICIDE RECYCLING PROGRAM

The West Virginia Department of Agriculture is conducting a Pesticide Recycling Program again this year.  Please contact Wayne Casto at 304-229-5828 (office) or 304-621-0336 (cell) for review and listing of your pesticide removal inventory.

ENTOMOLOGY

Tufted apple bud moth second generation egg hatch has begun and is estimated at 22% complete through August 6, based on an accumulation of 2371 degree days (DD) since biofix on May 3 at the WVU KTFREC.  Development is about 1 day ahead of last year based on DD accumulations through August 6.  The end of last week was the ideal time to initiate applications of Lannate plus an organophosphate [Azinphos-methyl (Guthion), Imidan] insecticide.  Applications of Intrepid, Rimon, or SpinTor should be initiated this week.  See the July 24th 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 93% complete through August 6, based on DD accumulations (1965) since biofix on April 26.  Third generation egg hatch is predicted to begin on August 12-15.   Insecticides should be applied for third generation control in those orchards where the pheromone trap capture exceeds 5 moths/trap/week.  If using Intrepid, Rimon, Assail, Calypso, Cyd-X or Carpovirusine, initiate control at 2160 DD after biofix (1% egg hatch, about August 12-15).  If using Avaunt, Azinphos-methyl (Guthion), Imidan or pyrethroids, initiate control at 2270 DD after biofix (6% egg hatch, about August 17-21).  An initial spray of any material should be followed by a second complete application in about 10-14 days, or up to three additional alternate-row-middle applications 5-7 days apart, if needed based on pheromone trap capture, proximity to harvest, and warm nighttime temperatures that favor continued mating and egg-laying. 

Oriental fruit moth third generation egg hatch is estimated at 84% complete on peach, based on an accumulation of 2745 DD since biofix on March 31.  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 Azinphos-methyl (Guthion) [21], Imidan [14], Ambush [14], Pounce [14], Proaxis [14], Warrior [14], Intrepid [7], Baythroid (7), Lannate [4], and carbaryl (Sevin) [3].  Control options on apple include Calypso [30], Asana [21], Battalion [21], Decis [21], Proaxis [21], Warrior [21], Azinphos-methyl (Guthion) [14], Intrepid [14], Avaunt [14], Danitol [14], Rimon [14}, Assail [7], Baythroid [7], and Imidan [7].  In addition, CheckMate OFM-F sprayable pheromone [0] 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.

Lesser peachtree borer and peachtree borer larvae can be controlled on peach and nectarine trees in the postharvest period (not necessary if pheromone mating disruption dispensers were applied earlier for adult control).  For lesser peachtree borer (LPTB), inspect wounded areas on the upper trunk, scaffold limbs and branches to determine the average number of empty pupal cases per tree protruding from the bark.  Also inspect wounds for evidence of larvae or fresh (amber colored) gum exudates mixed with wood borings and sawdust-like frass (excrement).  Control is recommended if there are more than a total of 2 larvae or empty pupal cases per tree.  For peachtree borer (PTB), inspect the base of trees for an exudation of gum containing frass and sawdust, and examine the soil at or near the base of trees for cocoons and empty pupal cases.  Control is recommended for trees up to 3 years old if any evidence of PTB infestation is detected.  In older orchards, an average of more than 1 cocoon and/or empty pupal case per tree would warrant treatment.  Chlorpyrifos (various 4E products and Lorsban 75WG available) is the preferred choice for postharvest control of either borer species.  Most effective control is achieved with a handgun application.  For LPTB control, thoroughly wet all wounds on the trunk, scaffold limbs and small branches.  For PTB control, thoroughly drench the lower trunk, allowing the liquid to pool at the base of the trees.

PHEROMONE TRAP COUNTS
WEST VIRGINIA UNIVERSITY KTFREC

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.   At WVU-KTFREC, we recorded only one significant wetting period since the last newsletter on July 24th (see the list below). Our total rainfall for the month of July was 2.22 inches at WVU-KTFREC and 2.53 inches at Butler's Farm Market. Our recent high temperature measurement was 98.2 F on August 3, 2006. Some scattered showers occurred on August 7, 2006, and may have provided wetting conditions favorable for disease development at some locations.

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

Accumulated wetting hours.   As of August 7, 2006, we have accumulated 414 wetting hours. Accumulated wetting hours are useful for predicting the appearance of sooty blotch on nonsprayed fruit. Sooty blotch and fly speck were first observed at WVU-KTFREC on nonsprayed fruit during the week of July 10th.

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.

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