August 15, 2005
|Upcoming Events||Pheromone Trap Counts||Plant Pathology|
September 14, 8:00 a.m. - noon. - Chemical Evaluation Field Day at WVU's Kearneysville Tree Fruit Research and Education Center. Pesticide Industry Representatives, Agricultural Research and Extension Personnel, Consultants and other interested persons are invited to tourc research plots and obtain preliminary results from evaluations of acaricides, insecticides and fungicides on apples and peaches. For more information contact the WVU KTFREC at 304-876-6353.
Tufted apple bud moth second generation egg hatch is estimated at 53% complete through August 14th, based on an accumulation of 2610 degree days (DD) since biofix on May 8. Based on forecasted temperatures, egg hatch is expected to continue for about two more weeks. See the August 1st issue of The Orchard Monitor newsletter for control options and application timings.
Codling moth second generation egg hatch is estimated to be 100% complete, based on DD accumulations (2133) since biofix on May 6. Third generation egg hatch is predicted to begin on August 16th. 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, Clutch, Cyd-X or Carpovirusine, initiate control at 2160 DD after biofix (1% egg hatch, about August 16th). If using Avaunt, Azinphos-methyl (Guthion), Imidan or pyrethroids, initiate control at 2270 DD after biofix (6% egg hatch, about August 20th). An initial spray of any material should be followed by a second complete application in about 10-14 days, or three additional alternate-row-middle applications 5-7 days apart.
Oriental fruit moth third generation egg hatch is estimated at 90% complete on peach, based on an accumulation of 2844 DD since biofix on April 11th. Egg hatch is lagging behind on apple due to slower development on this fruit crop. Because of 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) , Imidan , Ambush , Pounce , Proaxis , Warrior , Intrepid , Lannate , and carbaryl (Sevin) . Control options on apple include Calypso , Asana , Proaxis , Warrior , Azinphos-methyl (Guthion) , Intrepid , Avaunt , Danitol , Assail , Imidan  and Clutch .
White apple leafhopper second generation nymphs are beginning to appear on the underside 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. 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. Lorsban 4E 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
|DATE - 2005||RBLR||STLM||OFM||CM||TABM||DWB||LPTB||PTB||AM|
|DATE - 2005||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 two rain events since the last Orchard Monitor was published on August 1st. Other rain events have occurred in other locations, so your records may differ from those presented below. Total rainfall in the past two weeks has been 0.64 inches.
Table 1. Dates and conditions for summer infection periods at the WVU - KTFREC, 2005.
|No.||Date 2005||Hours/ degrees F|
|8.||June 2 - 3||33 hr/60° F|
|9.||June 6 - 7||12 hr/64° F|
|10.||June 9 - 10||13 hr/70° F|
|11.||July 5 - 6||18 hr/68° F|
|12.||July 8||18 hr/66° F|
|13.||July 13 - 14||15 hr/71° F|
|14.||July 15||7 hr/72° F|
|15.||July 16||10 hr/74° F|
|16.||July 16 - 17||14 hr/74° F|
|17.||July 25||6 hr/72° F|
|18.||Aug. 7 - 8||19 hr/69° F|
|19.||Aug. 9||14 hr/ 70° F|
Accumulated wetting hours. Threshold warning - threshold exceeded: As of August 15, 2005, we have accumulated 219 to 365 wetting hours, for petal fall dates of May 14 and May 7, respectively. Signs of flyspeck were first observed on July 20th at WVU - KTFREC (between 244 to 290 AWH depending on whether accumulations began on May 14 or May 7, respectively).
Red Raspberry Resistance to Phytophthora Root Rot. Based on trials conducted at the New York Agricultural Experiment Station in which several red raspberry cultivars were artificially inoculated with two strains of Phytophthora fragariae var. rubi, some commercially available cultivars show "high to moderate" resistance to Phytophthora root rot (an important contributor to decline of red raspberry plantings). The most resistant cultivars in the trials, in order of symptom severity (from least to most severe), were 'Prelude', 'Anne', 'Latham', 'Nova', and 'Josephine'. Cultivars with high severity of symptoms included 'Polana', 'Lauren', 'Titan', 'Encore', 'Autumn Byrd', 'Esquimalt', 'Cowichan', and 'Dinkum'. Cultivars with symptoms intermediate in severity to those of the other two groups were 'Killarney', 'Caroline', and 'Boyne'. From: J.A. Pattison and Courtney A. Weber (Dept. of Horticultural Sciences, New York State Agricultural Experiment Station, Cornell University, Geneva, NY 14456), "Evaluation of Red Raspberry Cultivars for Resistance to Phytophthora Root Rot," Journal of the American Pomological Society 59(1), January 2005, 50-56.
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