June 6, 2005
|Upcoming Events||Pheromone Trap Counts||Plant Pathology||Horticulture|
June 7, 6:00 p.m. - Tree Fruit Grower Twilight Dinner and Meeting at Butler's Orchard, Inwood, W. Va. To reach the orchard, travel 1.7 miles south on Arden-Nollville Road from the junction with Tablers Station Road at Arden to the entrance on the right at the brown brick home, or travel 2.5 miles north on Arden-Nollville Road from Inwood (exit 5 off I-81) to the entrance on the left. Dinner will be followed by a presentation on hire reporting requirements by Susan Mace, Program Coordinator with the West Virginia New Hire Reporting Center, seasonal updates by Extension Specialists from the WVU KTFREC, and a tour of the orchard by hosts Bill and Todd Butler. For more information contact the WVU KTFREC at 304-876-6353.
June 9, 6:30 p.m. - Joint PA, MD and WV Twilight Fruit Growers Meeting at Barr Orchards, Smithsburg, Md. The agenda will include an orchard tour, pest management update by Henry Hogmire, a two-prong approach to orchard weed control by Rob Crassweller, and an "ask the experts" question and answer session. WV growers will receive 4 credits for Pesticide Applicator Recertification. To reach Barr Orchards from Jefferson County, take WV-480 north through Shepherdstown, crossing the Potomac River onto MD-34. In Sharpsburg, turn left onto N. Church Street (becomes MD-65, Sharpsburg Pike). Follow MD-65 north until you intersect I-70 (approx. 10 miles). Take I-70 east for 5 miles to exit 35 - Smithsburg/Boonsboro (MD-66). Follow MD-66 north (left) towards Smithsburg for 5 miles. At the intersection of MD-66 and Smithsburg Pike/Jefferson Blvd. (MD-64), turn right. Proceed on MD-64 for about 4 miles, to a left onto Gardenhour Road (look for a big apple shaped sign for Gardenhour Orchards). You'll cross a small bridge at Gardenhour Orchards where the road turns to the right, then forks; take the left-hand fork onto Durberry Road. Follow Durberry Road for about 1.3 miles (past a sign for Barr Orchards on your left at a sharp curve in the road) to a long driveway that crosses a stream on your right (look for CREP hardwoods in grow tubes); turn right and proceed to buildings. From Berkeley County, take I-81 north to I-70 east to Exit 35, Smithsburg/Boonsboro (MD-66), and proceed as above. For more information contact the WVU KTFREC at 304-876-6353.
June 23, 6:00 p.m. - Twilight Fruit Growers Dinner and Meeting at Eli Cook's Farm, Slanesville, W. Va. To reach the meeting location from Slanesville, take Route 29 south for about 4 miles, turn left on Hickory Corner Road, and travel ¼ mile to the farm on the left. From Route 50, take Route 29 north for about 3.5 miles, turn right on Hickory Corner Road, and travel ¼ mile to the farm on the left. Dinner will be followed by seasonal updates by the Extension Specialists from the WVU KTFREC and a tour by Eli Cook. For more information contact the Hampshire County Extension Office at 304-822-5013.
July 13, 5:30 p.m. - Joint WV, VA and MD Twilight Fruit Growers Dinner and Meeting at the WVU Tree Fruit Research and Education Center, Kearneysville, W. Va. The agenda will include BBQ chicken dinner, exhibits, equipment demonstrations, updates by Extension Specialists, and a tour of research plots. To plan for dinner, reservations must be made by June 30. For more information or to make reservations, contact the WVU KTFREC at 304-876-6353.
July 14, 12:00-7:00 p.m. - Fruit Grower Field Day at the Penn State University Fruit Research and Extension Center, Biglerville, Pa. The agenda will include concurrent research and educational tours, and conclude with a dinner and invited speaker. Registration of $10, which includes educational handouts, drinks, and dinner, must be postmarked by June 30 (checks payable to Penn State University). For more information contact the PSU FREC at 717-677-6116 ext. 0.
Clutch T 50 WDG insecticide from Arvesta Corporation was recently registered by the EPA for use on apple and pear. As the newest member of the neonicotinoid chemical class, Clutch (clothianidin) is labeled at 2-6 oz/acre for the control of aphids, leafhoppers, leafminers, plum curculio, apple maggot, codling moth, oriental fruit moth, and pear psylla, and suppression of leafrollers. Application is limited to a season maximum of 6.4 oz of product (0.2 lb AI) per acre. Clutch has a 12 hour REI and 7 day PHI.
Tufted apple bud moth adults have been emerging since May 8 (biofix). First generation egg hatch is expected to begin at 480 degree days (DD) after biofix, which should occur on June 7, based on an accumulation of 433 DD through June 5 and warmer temperatures forecasted for today and tomorrow.
The objective in controlling this insect is to apply sprays during the period of egg hatch, which are best timed by using DD accumulations (45ºF lower and 91ºF upper threshold temperatures) after biofix. Options for controlling the first generation include Intrepid, SpinTor, Avaunt, BT, or an organophosphate insecticide [azinphos-methyl (Guthion), Imidan] with Lannate. Intrepid and SpinTor will provide the best control in most West Virginia orchards. It is recommended that either of these two products be applied as a complete spray at 585-640 DD (20-30% egg hatch, expected on June 10-12) or as two alternate-row-middle applications 7 days apart beginning at 530 DD (10% egg hatch, expected on June 8). An additional application may be needed (in 14 days for complete, in 7 and 14 days for alternate-row-middle) in high pressure situations. If using Avaunt, BT, or an organophosphate in combination with Lannate, make complete applications at 530-585 DD (10-20% egg hatch) and 805-855 DD (60-70% egg hatch). Alternate-row-middle applications of these materials are recommended at 475-505, 610-640, 750-775 and 885-910 DD, which coincide with 0-5, 25-30, 50-55 and 75-80% egg hatch, respectively.
Spirea aphids have increased on the terminals of apple trees, and will continue to be abundant for the next 2-3 weeks. In most situations, low to moderate populations of these aphids can be tolerated without detrimental effects. High populations can stunt the growth of young trees, and indirect injury can result when aphids excrete large amounts of honeydew which supports the growth of a sooty mold that discolors the leaves and fruit. The accumulation of honeydew is influenced by the amount of rainfall (less under wet conditions).
Examine the foliage and fruit for buildup of honeydew, and monitor aphid abundance by sampling 10 actively growing shoots (not watersprouts) on each of 5-10 trees per block. On each shoot, determine the number of leaves that have wingless aphids and calculate the average number of aphid infested leaves per shoot across all trees sampled. Also examine shoots and aphid colonies for the presence of aphid predators, such as ladybird beetle adults and larvae, and larvae of syrphid flies, aphid midges and green lacewings. The likelihood of biological control success from these predators has increased because of changes in pest management programs for tufted apple bud moth. Substitution of Intrepid or SpinTor for Lannate has permitted increased survival of these beneficial insects to reduce aphid populations.
An insecticide application is recommended for spirea aphid control if an average of four or more infested leaves per shoot are found, and less than 20% of the aphid colonies have predators. Materials for control include Provado, Actara, Assail, Calypso, Clutch, Lannate, Dimethoate, and Thionex.
San Jose scale infestations continue to occur in some orchards. Crawler emergence has begun and should be monitored in those blocks that had at least 1% scale injury on fruit at harvest last year. Crawlers generally begin to emerge about 3-4 weeks, or at 300-350 DD (base 50°F), after the first male catch in a pheromone trap. Crawler emergence can be detected by wrapping black electrician's tape (sticky side out) around scale-infested branches. A thin film of petroleum jelly may be spread on the tape surface to enhance crawler capture. Inspect the tape traps twice weekly for the bright yellow crawlers. On apple, apply Esteem, Centaur, Diazinon or Provado, preferably as a high volume spray, when crawlers are first detected and again in about 10 days. San Jose scale may also infest peaches and can be controlled with Diazinon. Adequate coverage of the tops of trees is critical to control of this insect.
Oriental fruit moth hatch of first generation eggs is complete and the second flight of moths has begun. Orchards should be inspected for shoot injury at this time in order to evaluate the effectiveness of first generation control measures.
There are various options for controlling the second generation. One strategy that could be targeted against adults is pheromone mating disruption, with various hand applied dispensers and a sprayable pheromone available. A second strategy is to control larvae later this month with insecticides in those orchards where the pheromone trap catch exceeds 10 moths/trap/week. On peach, apply azinphos-methyl (Guthion) or Imidan at 1150-1200 DD after biofix (15-20% egg hatch). A second application may be needed at 1450-1500 DD after biofix (65-72% egg hatch) in high pressure situations. On apple, apply Intrepid, Assail, Calypso or Clutch at 1350-1400 DD after biofix (45-55% egg hatch), or Avaunt, azinphos-methyl (Guthion) or Imidan at 1450-1500 DD after biofix (65-72% egg hatch).
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 and apple scab. We recorded two new infection periods since the last Orchard Monitor was published on May 23rd. On May 23 - 25, we experienced 42 hours of wetting at an average temperature of 54° F. A second wet period occurred on June 2 - 3 with 33 hours of wetting at 60° F. Visible scab lesions have been reported from Jefferson County, West Virginia, on May 12, 2005. In orchard blocks with established scab lesions, consider making two to three applications of captan over a 3-week period. Captan and the current temperatures in the mid to high-80's should act to diminish the production of conidia on lesions and protect the fruit from further infection.
Table 1. Dates and conditions for apple scab infection periods at the WVU - KTFREC, 2005.
|No.||Date 2005||Hours/ degrees F|
|1.||April 7 - 8||14 hr/58° F|
|2.||April 22 - 23||33 hr/52° F|
|3.||April 30 - May 1||19 hr/57° F|
|May 12||Scab lesions observed in Jefferson County, W.Va.|
|4.||May 14 - 15||15 hr/64° F|
|5.||May 19 - 21||18 hr/54° F|
|6.||May 21 - 22||13 hr/48° F|
|7.||May 23 - 25||42 hr/54° F|
|8.||June 2 - 3||33 hr/60° F|
Fire blight. Conditions favorable for fire blight occurred on April 20th, if wetting occurred on the 19th or 20th. Symptoms from that infection would have been visible on or around May 14. The weekend of May 14 - 15 also experienced weather favorable for fire blight infection on both days. Symptoms are visible from the blossom infections. Shoot blight has been observed developing in the immediate vicinity of infected blossoms, which developed in the immediate vicinity of overwintering cankers.
Summer fungicide programs. Excellent control of our summer disease complex can be achieved with well-timed fungicide sprays. Timing is one of the most important aspects of effective disease management. As always, read the labels for more detailed information about these materials.
1. EBDC fungicides (Dithane, Manzate, Penncozeb, Polyram): Will provide excellent control of summer diseases when combined with Captan, Ziram, or Topsin-M. EBDC's can be applied up to 77 days before harvest when using the extended application schedule at the 3 lb per acre rate. Early use of these materials provides the foundation for managing these diseases for the remainder of the season.
2. Topsin-M: Highly effective against sooty blotch, fly speck, and the Botryosphaeria rots (black rot and white rot). In wet growing seasons, the spray interval should not be longer than 14 - 21 days, or 2 inches of rain. Adjust the rates of Topsin-M toward the high end of the rate range (10 oz per acre) when disease conditions are highly favorable. Use Topsin-M in mixtures with protectant fungicides to help prevent the emergence of fungal strains resistant to Topsin-M.
3. Protectant fungicides (Captan, Ziram, Sulfur): Captan and Ziram applied by themselves or in combination will provide adequate control of summer diseases if applied often enough at the proper rates (6 to 8 lb per acre total). Spray intervals should be 21 days under moderate disease pressure, and should be shortened to 10 - 14 days under prolonged, highly favorable conditions. The 8 lb per acre rate also is preferred under highly favorable conditions. Sulfur by itself is only fair, at best, in limiting these diseases. However, sulfur and copper are the only choices for organic spray programs. Under extreme disease pressure, the addition of Topsin-M at a "half rate" improves control of Botryosphaeria rots and sooty blotch and fly speck. Where scab is well established, captan (8.0 lb. per acre) is the better choice to limit secondary infections.
4. Strobilurin fungicides (Sovran and Flint): These fungicides are very effective for controlling fly speck and sooty blotch and could be used as substitutes for Topsin-M + protectant (captan or ziram) sprays during summer. The best timing for Sovran and Flint in summer sprays remains to be determined. If Sovran or Flint were used to control scab at tight cluster and pink, then they should not be used again prior to second cover. Sovran and Flint suppress sporulation of scab lesions, so their use at this time may be beneficial if your control of primary scab hasn't been completely effective. During early summer, good spray coverage is still possible whereas dense foliage, fruit clustering, and limbs drooping under heavy crop loads often compromise spray coverage in late summer. However, if Sovran or Flint is applied at petal fall and first cover, then additional summer applications would need to be delayed until July or August because of the requirement for intervening applications with some other class of fungicides.
Sovran has a 30-day preharvest interval and the label indicates that it should not be used as the last spray of the season. This prohibition was based on the assumption that growers might apply Sovran for scab control starting at green tip, and using it both to end the season and begin the following season would compromise resistance management. Flint has a 14-day preharvest interval. Both Flint and Sovran have residual activity against fly speck, although recent research suggests that the residual activity is not equivalent to that provided by Topsin-M.
Summary. Control of early-season diseases with a program that includes an EBDC material, alternated with the strobilurin fungicides, provides a solid foundation for controlling summer diseases. The most flexible program for controlling sooty blotch and fly speck is ziram or captan + Topsin-M, and optionally alternated with two applications of the strobilurin fungicides. This program may need to be modified if other summer diseases occur at moderate to high levels. For example, the combination of ziram + Topsin-M is rated as only "good" (rather than "excellent") against white rot and black rot, and is only "fair" against bitter rot. Alternating applications of ziram + Topsin-M or captan + Topsin-M with full rates of ziram or captan alone will improve your management of the summer rots. Remember that management of diseases with fungicides is improved if other cultural practices that reduce inoculum and improve coverage are employed. Good disease management may require some flexibility in application timing and rates of materials.
Accumulated wetting hours. As of June 6, 2005, we have accumulated 100 to 146 wetting hours, for petal fall dates of May 14 and May 7, respectively. 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.
See our "Current Conditions" Web page for details that are updated at least three times weekly.
Provide® for Improving Fruit Finish
Fruit russetting is a common disorder that reduces the market value of 'Golden Delicious' in most years. Provide® is a combination of gibberellins that may reduce the severity of russet on 'Golden Delicious' when applied during the first 50 days after bloom.
Apply Provide® in 2-4 consecutive sprays, beginning at late bloom to petal fall, and continuing at 7-10 day intervals for remaining sprays. Apply 10-13 oz of Provide® in 100 gallons of spray solution per acre. Do not apply more than 40 oz in a single season. Do not use spreader stickers or other spray adjuvants in combination with Provide® because they may aggravate russet development. Provide® can be used to suppress russet of varieties other than 'Golden Delicious.'
Provide® for Reducing 'Stayman' Cracking
Provide® is a mixture of gibberellins that can reduce 'Stayman' cracking if applied before cracking begins. Apply Provide® 3 or 6 times at 14- to 21-day intervals, starting 2 to 3 weeks before cracking begins (mid-June to early July). Apply Provide® at the rate of one to two pints per acre per application and enough water should be used to wet the fruit (100 to 200 gallons per acre). Do not apply more than 12 pints in a single season. If Provide® is used to suppress russet on 'Stayman,' it cannot be used to suppress cracking. See pages 127-128 of the 2005 Spray Bulletin for more information.
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