RUTGERS COOPERATIVE EXTENSION
of Hunterdon, Morris, Somerset, Sussex and Warren Counties
New Jersey Agricultural Experiment Station
NORTHWEST JERSEY
PRODUCTION NEWS
Horticultural Information for the Commercial Grower
In Hunterdon, Morris, Somerset, Sussex and Warren Counties
Vol. 7 No. 4 May 8, 1997
SECOND NORTH JERSEY TWILIGHT FRUIT MEETING
Thursday, May 15, 1997
Terhune Orchards
Princeton, NJ
Apple Thinning and Foliar Nutrition for North Jersey
Win Cowgill, RCE
Area Fruit Agent
Regional Fruit Crop Outlook/Fruit Thinning
Considerations
Dr. Robert Belding, RCE
Extension Specialist in Pomology
Tree Fruit Insect Pest Management Update
Dr. Peter Shearer, RCE
Extension Specialist in Entomology
Pesticide/Worker Protection Standard Update
Carmen Valentin
Public Outreach Coordinator (NJDEP)
Tree and Small Fruit Weed Control
Dr. Brad Majek, RCE
Extension Specialist in Weed Science
Pesticide Units
1 Core 4 PP2 4 1A
6:00-7:00
Orchard Tour
Gary and Pam Mount have a diverse fruit growing operation. During the orchard tour we will see:
* a 20 year old block of Red Delicious and Stayman on M-26
* newly established staked apple plantings on M-9 and Crispin on M-27
* high density peach block
* new raspberry plantings
* a 9 year old blueberry planting - 2 acres - which is covered with bird netting.
* new pesticide/spray shed facility
* demonstration of VICON spreader
* cider pressing equipment
7:00-9:00
North Jersey Fruit IPM Update/Blueberry IPM
Dean Polk
Rutgers Cooperative Extension
NJ Fruit IPM Agent
Ken Petersen, RCE
North Jersey IPM Program Associate
Tree Fruit Disease Control Update
Dr. Norman Lalancette, RCE
Extension Specialist in Plant Pathology
Directions to Terhune Orchards:
From the North: Take Route 31 South, make left turn onto Route 518 East to Hopewell. In Hopewell make right turn onto Carter Road (Route 569). Proceed South on Carter Rd. for approx. 6 miles to Cold Soil Road (right turn). Farm is on left. From the South: Take Route 206 North from Lawrenceville, make left onto Carter Road (Route 569). Approx. 2 + miles to Cold Soil Road make left turn - farm on left. Terhune Orchards - 609-924-2310
Cooperating Agencies: Rutgers, The State University of New Jersey, U.S. Department of Agriculture, and County Boards of Chosen Freeholders. Educational Programs are offered without regard to race, sex, age, handicap or disability, color or national origin. Rutgers Cooperative Extension is an Equal Opportunity Employer
Cider Recommendations
The Food and Drug Administration recently recommended that all apple cider be pasturized. These recommendations are not yet the law and it is unclear if, and when, they will be. The US Apple Association has developed a survey for cider producers to receive input about the FDA proposals. If you would like to participate in the survey, call the USAA at (800) 781-4443.
Catfacing insects: Both tarnished plant bugs and stink bugs can be found in low numbers in sweep samples. In most cases, no catfacing insect activity is being seen. Where present, insects can be found at 1 to 3 adults per 50 sweeps. If the first sprays have been applied for OFM, the present catfacing insect pressure does not justify any additional insecticides until needed for the second OFM treatment. While pyrethroids (Ambush, Pounce, Asana) will control both OFM and catfacing insects, their use will build mite populations. While we have effective miticides, repeated pyrethroid/miticide programs do not make for good resistance management,and will eventually lead to increased use and pesticide costs.
Green peach aphids: Aphids are starting to show up in a few blocks. Highest levels average .3 colonies per tree.
Apple
European red mite (ERM): Mites are present, but average less than 1 mite per leaf where present, although certain spots have up to 5 mites per leaf. Growers who are trying to decide on early miticide treatments can consider Agrimek, Vendex, or Kelthane. Given the present timing, Agrimek will probably give the most consistent results, and control early spotted tentiform leafminer. If using Agrimek, remember that it must be combined with oil, or a silicon based penetrant. According to Merck these include: Silwet, Kenetic, and Silguard. Other suitable penetrants include LI700 and Regulaid. Do Not use plant oil based surfactants, since they will cause phytotoxic results; and stay away from non-ionic surfactants, since most of these are wetting agents, spreaders and stickers, but not penetrants.
Codling moth: The first adults were caught in pheromone traps
in southern counties on 4/30, 5/2, and 5/4 (Burlington Co.). The first generation
flight will peak in about 2 to 3 weeks, which will roughly coincide with
the first insecticides that are due for this insect. The first CM sprays
should be applied after 250 DD (base 50) have accumulated since first catch.
Fruit IPM
5/6/97
Please Note: This week's IPM Newsletter information is being mailed to you because there is an omission in the Plant & Pest Advisory Fruit
Edition of May 6. The degree day table that is in the last part of this newsletter was not included in the regular edition. Please note the 200 DD and 400 DD spray timings for OFM treatment as they relate to your area. Please also note that this version does not have the Trap Count or Blueberry sections, since these sections did not relate to the degree day table at the end.
Thank you.
Dean Polk
IPM Agent-Fruit
Peach
Oriental fruit moth (OFM): The first sprays for first generation
OFM should already have been applied in southern counties. We have a week
to 10 days to go before the second application is applied at 400 DD after
biofix (predicted at 5/12 in Hammonton). The first treatments will be due
in central counties (Mercer/Monmouth) by the end of the week, and in northern
counties by the follow
Production News, 1997 Page
White apple leafhopper (WALH): Nymphs are starting to hatch, and
are being seen well below treatment thresholds. This insect should not be
a target in the petal fall spray, unless it is controlled by a product already
being applied for another pest.
Spotted tentiform leafminer (STLM): Sap feeding miners are present at low numbers in some plantings, but few eggs have been seen. Given the relatively low number of mines being seen, any (petal fall) applications of Provado or Agimek can probably be delayed about a week. Delaying applications until mines are present will result in improved control.
European apple sawfly: Sawfly eggs were seen on poorly sprayed trees this past week. If growers have had sawfly damage in the past, then petal fall sprays should not be delayed, and applied in a full cover (both sides) application. Newly emerged larvae will mine just under the skin of the fruit and produce a small serpentine scar at the calyx end.
Disease
Apple scab: The last wetting events registered infection periods on 4/27 (.75"), and again on 5/3 (.87") in Gloucester County. Powdery mildew is present on a number of Rome blocks. The proximity of powdery mildew on apples is a major factor in rusty spot infection on peaches. If susceptible varieties of peaches are planted close to Rome apples, the peach blocks should be treated with Nova for rusty spot control.
Tree Fruit Pest Degree Day Accumulations Since 1st Catch
Skybit as of May 5, 1997
Site Biofix/1st OFM
Catch Date
Hammonton - At. Co. 3/25 331
Hardingville - Glou. Co. 3/30 286
Bridgeton - Cumb. Co. 4/7 228
Princeton - Mercer Co. 4/1 157
Oldwick - Hunt. Co. 4/21 140
Hackettstown - War. Co. 4/28 90
Summary of Apple Thinning for
North Jersey
Win Cowgill, County Agricultural Agent
Rutgers Coop. Extension of Hunterdon County
No single practice in apple production will have a greater impact on the bottom line than the utilization of plant growth regulators (PGR's) for chemical thinning.
Chemical thinning stabilizes annual crop production and improves size, color and quality of fruit. Research has shown that fruit size is directly related to how early fruits are thinned. Thinning that reduces the clustering of fruit will improve fruit color and quality. Adequate chemical thinning will promote or guarantee return bloom, and promote consistent annual production of crops.
No single thinning program is applicable to all orchards because of the many variables. Past experience combined with detailed records of materials, rates, crop performance, crop management practices, yield and weather conditions are you best guide.
It is essential to understand which thinning materials are available, how they work, and the different windows of opportunity available for their application. Knowing the cultivar response to these different materials will greatly increase the success of your thinning program.
If you have specific thinning questions do not hesitate to call me.
Windows of application for thinning apples
Bloom thinner's-the only labeled material in NJ is Wilthin. It is a new material that has been written up in many popular articles. Applied at 70-80% full bloom at 2-3 pints per 100 gallons of water at a minimum of 150 gallons of water per acre. It has been effective primarily on the west coast on Red Delicious cultivars. In last years trials in Hunterdon County, NJ on Macouns, no significant difference was seen on thinning or on return bloom this week.
Not enough information is available yet on this product on east coast varieties to gauge its effectiveness. Indications are that much higher rates are needed on the east coast. Additional research this year should provide better information.
Production News, 1997 Page
Bloom thinning is a good idea in apple production theoretically, as the
earlier we thin the better fruit size that can be obtained.
Thinning early lets us come back for repeat applications with other materials if necessary at petal fall and later.
Petal Fall Window (PF up to 8mm size)
All labeled thinning materials are effective at this time including NAA, NAD, ACCEL, Vydate, Sevin. Thinning early gives us greater fruit size, but usually at PF we do not take enough fruit off and must come back again with another application.
Early Fruit Set Window (8mm up to 12mm)
This is the traditional time for chemically thinning apples. All labeled thinning materials are effective at this time including NAA, NAD, ACCEL, Vydate, Sevin. Slightly higher rates are needed on some materials, combination treatments have generally been more effective than single materials.
Late Fruit Set Window (15-20MM)
All labeled thinning materials are effective at this time including NAA, NAD, ACCEL, Vydate, Sevin. The high rates of these materials must be used at this timing.
· In general early applications of good rates thin aggressively. Moderate and mild thinning occurs at lower rates and/or at later timings.
· Rates of individual thinners and/or combina- tions should be based on past grower experi- ence with individual cultivars in each fruit block or use variety and rate guidelines as outlined in our 1997 NJ Commercial Tree Fruit Manual.
Some notes on thinning from North Jersey research and demonstration trials and 19 years of observation
· Climatic conditions cannot be controlled but can greatly effect the strength of fruit set and the effectiveness of chemical thinning materials.
Dr. Rich Marini, VPI reports that a combination of temperature , humidity, wind and elevation will all effect chemical activity. Thinners when applied during poor drying conditions will general increase activity. Dew or light rain following treatment may resuspend the chemical and cause additional uptake.
Cloudy conditions cause shading and reduce carbohydrate levels in young fruits, causing poor fruit retention. Marini reports applying thinners just before, during, or just after a three day cloudy period, especially when temperatures are above 65F would likely increase the thinning response.
Michigan information indicates that thinning activity is related to temperature with more activity when materials are applied in a warming trend.
What does the above mean to you the grower? It means that good records and daily observation are essential when working with chemical thinners. Rates, materials and timing must be adjusted based on the seasons current weather conditions.
Chemical Choice
NAA- is one of our oldest and most reliable thinners. It can be applied from petal fall to 20MM fruit size at rates of 5ppm to 20ppm per 100 gallons.
Caution: on red delicious do not apply concentrations more than 5ppm to avoid pygmy fruits. Do not use NAA or NAD on any trees that are to be treated with Accel, Promalin or Provide this year! Pygmy fruits may result.
NAD- is a mild form of NAA and is used at PF and early fruit set only! It is very affective on summer varieties such as Paulared, Jerseymac, Macintosh cultivars and Macoun. It is usually applied at 40-50 ppm per 100 gallons at PF-5mm. (See above caution).
Accel- is a newer material that works as a mild thinner but has
the ability to increase fruit size over and above the thinning response.
It is valuable for use on small fruited cultivars like Empire. (See Dr.
Ed Stover Comments Below). It is best applied PF to 8mm and used at the
maximum rate which is 30
Production News, 1997 Page
gms/A. It is best used in combination with other materials for effective
thinning. Sevin or Vydate are our two choices for combination.
Caution: Do not use on any trees treated with NAA or NAD this year, they are not compatible. Avoid drift on threes that have been treated with either NAA or NAD.
Sevin is a carbamate insecticide that is a standard thinner for apples. Only Sevin XLR-Plus should be used. It is safer on bees and has been reported to have less toxicity to mite predators. It has the same concentration of active ingredient as Sevin 50W and thins the same way. Sevin is a mild thinner at the full rate 1quart/acre. It can be used at PF till 20 mm and is best used in combination with other thinners (NAA or Accel) with most varieties. When used alone it may underthin some cultivars in NJ. (Do not use Vydate in combination with Sevin).
Vydate L is a carbamate insecticide that works the same way as Sevin. It has been a state label in NJ since 1996 based on our research trials in North Jersey. It too is a mild thinner like Sevin and should be used in combination with another thinner for best results (NAA or Accel). At 1-2 pints per 100 gallons it should be applied dilute between PF/5MM and 20MM. Up to two applications can be made per season. Vydate may be less toxic to mite predators than Sevin and at the 1-2 pint /100 rate may have activity on spotted tentiform leafminor and white apple leafhopper.
The following are
summaries and comments
from Dr. Ed Stover
formally of the Cornell Univ. Hudson Valley Lab
Time of Thinning
· in general earlier thinning will give larger fruit size at a comparable cropload.
· use of multiple thinning treatments may give
better control of cropping in difficult to thin blocks, with higher profitability
and probably better return bloom.
· NAA/Sevin on "Empire': 1) has been remarkably consistent from petal fall through 15 mm king fruit diameter (KFD), but usually yields better fruit size relative to cropload comparable to the best Accel/Seven treatments; 3) usually breaks up clusters more effectively than Accel/Sevin.
Use of Accel
· much more consistent response from Accel/ Sevin combination than Accel alone, still more variable than NAA/Sevin.
· no benefit to using Accel unless you get significant enhancement of fruit size.
· in 'Empire' best fruit size enhancement from Accel around 10 mm KFD, some response at 5-15 mm KFD but only thins from earlier treatments.
· with 'Empire', in most cases, Accel/Sevin gives substantially greater crop value than NAA/Sevin.
· excellent results in 'Empire' from using Accel or Accel/Sevin at 10 mm KFD after earlier thinning treatment: resulted in similar fruit size advantage relative to cropload as Accel/Sevin alone.
· we had poor results with Accel or Accel/Sevin in 'Delicious' in 2 of 3 years of trials; other researchers (especially in Mid-Atlantic) report better response with lower rates than we have tried. Note: Accell/Sevin has not provided good results in nothern NJ as well on Red Delicious, it has provided good results on Macintosh (Win Cowgill).
Effect of Environmental Conditions
· in two years of trials there has been no significant difference
in thinning or fruit size from NAA/Sevin or Accel/Sevin when applied in
Production News, 1997 Page
days with high temperature of 58-60 degrees F vs. 70-75 degrees F.
· in one year there was significantly more thinning when Accel was combined with oil, Silwet, or Sevin as opposed to Regulaid or no adjuvant when rain followed within two hours of application.
· it appears that prolonged uptake under cool conditions that provide long drying may be as effective as more rapid but shorter uptake under warm "ideal" conditions.
· there is considerable evidence that warm weather in the few days after application is the most important weather consideration for good thinning.
Economics of Apple Thinning
· for most 'Empire' blocks, greatest profitability (considering only the current season) is at croploads too high to ensure good return bloom thus greatest long term profitability result from pushing cropping near but not up to the point of compromising return bloom.
· to achieve croploads near the point of maximum economic return it will be necessary to: keep records on cropload and returns within each block; and thin some blocks in stages, evaluating cropload before each subsequent treatment.
· depending upon the block and the growing season, 40-75% 100 count fruit may yield the highest returns in "Empire" - thinning to higher percent 100s, reduces number of 120's without increasing 100s.
· for "Empire" in most blocks, use of Accel or Accel/Sevin will likely enhance profits .
· in many "McIntosh" blocks, significant thinning reduces profit in such blocks it is probably best to use either Sevin only, 3 ppm NAA only to break up clusters, or 35-50 ppm Accel only to enhance fruit size.
Recommendations for Apples
From Ed Stover, Hudson Valley Lab
· prepare to apply your primary thinner (NAA/Sevin, NAA alone, or Sevin alone) as early as conditions permit following petal fall. Make this application when conditions are good and warm weather is expected within 1-3 days.
· When poor weather conditions prevent thinner application to all blocks under ideal conditions if warm conditions are expected in the next 2-3 days, rather than delay application to large fruitlet size, it is probably better to make some applications when conditions are cool but provide good spray coverage.
· in "Empire", Accel/Sevin appears to be the best choice when a single thinning treatment will be used.
Suggested Beginners Chemical Thinning Program
From Win Cowgill
For growers who have never chemically thinned before or are nervous about chemical thinning (if all the above is Greek to you, try the following program developed by Mike Thomas, retired fruit agent, MSU). I have used this program with numerous growers in northern New Jersey with good success. The idea is to get some NAA on all apples. NAA will give some thinning response and will assist with return bloom. The number of application you make will depend on your comfort level and the weather.
NAA is one of our oldest most reliable thinners. It is effective from bloom until 20mm fruit size, some times are more optimal than others. NAA does not have a 'memory' and multiple applications after 24 hours are not cumulative.
Spray #1- at petal fall of your latest blooming variety, apply 3-5ppm
NAA/100 gallons on all apples (whether you think they need thinning or not).
Do not use this method on varieties ripening earlier than Paulared.
Production News, 1997 Page
Wait 5-7 days. Evaluate thinning results.
Note: no additional applications should be made to spur red delicious.
Spray #2-Apply 7-15ppm of NAA/100 on those varieties that still need thinning.
Wait 5-7 days and evaluate thinning.
Spray #3- Apply 10-20ppm of NAA/100 on varieties that still need additional thinning.
Wait 5-7 days and evaluate thinning.
Spray #4 - Apply 20ppm NAA/100 and 1 Quart of Sevin-XLR-Plus/A. This is a desperation spray.
There are a few other rules to follow with this program:
· If you need a lot of thinning use the higher rates.
· Apply early morning or late evening to get slow drying.
· Spray dilute mixtures.
· Make sure your sprayer is calibrated. On most medium density planting systems with airblast sprayers, 2/3 of the spray should be directed to the tops of the trees, so as to not overthin (overapply) the lower branches.
New Jersey Nursery and Greenhouse
Film Recycling Project
In an effort to provide NJ growers with an alternative to disposing of used greenhouse and nursery films in the landfill, a project has been developed to recycle this material. Nursery overwintering films (both white and clear) and clear multiseason (2yr., 3yr, 4yr) greenhouse covers will be collected for recycling this spring. Collection sites conventiently located in Central andSouthern NJ will be accepting deliveries of plastic film from March 15, 1997 through June 30, 1997.
There is no charge for dropping greenhouse or nursery film off at any approved collection site. Growers from all counties in NJ can participate. Since this is a recycling project, the transporting vehicle does not have to be registered as a solid waste hauler with the NJDEP. You can haul the plastic film to the collection site yourself or contract with a third party. The participating collection sites, sponsored by Monmouth, Burlington and Cumberland Counties, will waive tipping fees for all greenhouse and nursery plastic delivered to the approved collection sites. This applies to growers from any area of NJ - not justs the three counties listed.
This project is jointly sponsored by AT Plastics Inc., NJ Dept. of Ag., NJ Nursery and Landscape Assoc., Inc., NJ Dept of Environmental Protection, Rutgers Cooperative Extension, E.C. Geiger, Inc., Monmouth County, Burlington County Office of Solid Waste, and the Cumberland County Improvement Authority.
For more information, please contact: NJ Dept. of Agriculture (609) 984-2506;
NJNLA (609) 291-7070; AT Plastsics, Inc. (800) 661-3606. Or your County
Extension Office.
DID YOU KNOW Rutgers Cooperative Extension offers educational programs without
regard to race, sex, age, handicap or disability, color or national origin?
Rutgers Cooperative Extension is an equal opportunity employer.
Production News, 1997 Page