Back to top

Healthy Fruit 2011 Vol. 19:13

Jul 5, 2011

Current (through July 4) degree day (DD) Accumulations

Location: UMass Cold Spring Orchard (CSO), Belchertown, MA

Base 43: 1548

Base 50: 1059

Significant upcoming orchard insect events based on degree days (Base 43):

Obliquebanded leafroller summer larvae hatch: 1038-1460

Apple maggot 1st catch: 1230-1632

Peachtree borer 1st flight catch: 789-1353

Oriental fruit moth 2nd flight begins: 1281-1491

Redbanded leafroller 2nd flight begins: 1244-1576

Orchard Radar insect synopsis

Note: with each issue of Healthy Fruit we will be reprinting selected apple insect degree-day model highlights from Glen Koehler's (U. of Maine) Orchard Radar output for Belchertown, MA.

  • Codling moth (CM), 1st generation adult emergence at 100% and 1st generation egg hatch at 94%. 2nd generation 7% CM egg hatch: July 27, Wednesday, = target date for 1st spray where multiple sprays needed to control 2nd generation CM (if needed and allowed by pre-harvest interval).
  • 1st generation obliquebanded leafroller (OBLR) flight begins around: June 5, Sunday. Early egg hatch and optimum date for initial application of B.t., Delegate, Proclaim, Intrepid, Rimon, Altacor, Belt, pyrethroid or other insecticide effective against OBLR (with follow-up applications as needed) : June 21, Tuesday. Where waiting to sample late instar OBLR larvae to determine need for treatment is an option, or to check on results from earlier sprays: Optimum sample date for late instar summer generation OBLR larvae: July 1, Friday. If first OBLR late instar larvae sample is below threshold, date for confirmation follow-up: July 4, Monday.
  • Oriental fruit moth (OFM) 2nd generation OFM flight begins around: June 27, Monday. 2nd generation - first treatment date, if needed: July 4, Monday.2nd generation - second treatment date, if needed: July 15, Friday.
  • 2nd redbanded leafroller (RBLR) flight begins around June 28, Tuesday. Peak catch and approximate start of egg hatch: July 10.
  • Spotted Tentiform Leafminer (STLM): 2nd STLM flight begins around: June 12, Sunday. Rough guess of when 2nd generation sap-feeding mines begin showing: July 3, Sunday. Optimum first sample date for 2nd generation STLM sapfeeding mines is July 9, Saturday. Second optimized sample date for 2nd generation sapfeeding mines, if needed: July 15, Friday.
  • Rough guess of date first apple maggot flies (AMF) are caught on traps is: Tuesday, June 28. Rough guess of peak AM trap captures is: August 1, Monday.

Orchard Radar preliminary McIntosh harvest date forecast

Harvest date estimates are based on temperature observations from the first 30 days after Full bloom.

  • Date to apply ReTain to delay first harvest for apples which without treatment would be ready for storage harvest on September 5 is Monday, August 8. Begin measuring actual McIntosh starch-iodine index no later than Wednesday, August 24.
  • The Michigan formula estimates that non-spur McIntosh will reach starch index 4.0 and start the optimum harvest window for long term storage on Monday, September 5.
  • Using the Hudson Valley NY formula, McIntosh maturity is forecast to reach starch index 6.0 in
    Belchertown MA on Wednesday, September 21.

Upcoming meetings

July 13, 2011: TREE FRUIT TWILIGHT MEETING Poverty Lane Orchards, 98 Poverty Lane, Lebanon, NH. 5 PM. Sponsored by U. of New Hampshire Cooperative Extension and New Hampshire Fruit Growers' Association. 2 pesticide re-certification credits. Contact Heather Bryant (603-787-6944) for more information.

July 18, 2011: Massachusetts Fruit Growers' Association Summer Meeting, Parlee Farms, Tyngsoboro, MA.

August 3, 2011: Lake Ontario Summer Fruit Tour, Presented by Cornell Cooperative Extension, Cornell University, & the New York State Agricultural Experiment Station.

The way I see it

Classic summer weather is here. Some spots have received more rain than others. It's actually drying out a bit in some orchards -- don't hesitate to run trickle irrigation where you have it.

You should be scouting for obliquebanded leafroller now, and if necessary treat ASAP. From this week's Scaffold Fruit Journal:

Populations of OBLR have not been very high the last couple of years, but for whatever reason, they seem to be rebounding with renewed vigor in WNY this season. Pheromone traps in some Wayne Co. orchards have been catching upwards of 50–60 moths per week, and larger larvae are easily able to be found in growing terminals of certain apple varieties. From the generalized biofix period spanning June 1–14 (Hudson Valley to WNY, respectively), we have accumulated anywhere from about 460–850 DD base 43F. This represents egg hatch as being 25% to over 90% complete, and the timing for the larger (IV instars and beyond) caterpillars that are large enough to start doing noticeable damage to foliar terminals and, ultimately, the young fruits. Moreover, with the predicted week-long stretch of continued warm temperatures, we will be accumulating an additional 30 DD or so every day, which will further boost the progress of larval development. Sampling for evidence of a treatable OBLR infestation is recommended now in orchards where a preventive spray has not already been applied; see p. 69 in the Recommends.

Repeating our treatment guidelines from last week: Delegate, Belt, Altacor and Proclaim are our preferred choices in most cases; Rimon, Intrepid, a B.t. material or a pyrethroid are also options, depending on block history and previous spray efficacy against specific populations. If the average percentage of terminals infested with live larvae is less than 3%, no treatment is required at this time, but another sample should be taken three to five days (100 DD) later, to be sure populations were not underestimated.

I was out hand-thinning Honeycrisp apples yesterday and came back to the office with a Japanese beetle on my hat. They love Honeycrisp (and cherries, and peaches) and things can get out of control fast unless you keep an eye out for them. Suggested chemical treatments include: Assail, Calypso, Voliam Xpress or Sevin (in apple) or Assail, Leverage, Voliam Xpress, or Provado (in cherries; add Sevin to the list for peaches).

Also watch for potato leafhopper and treat young orchards at the first sign of infestation. The list of chemical control options is long, including (all rated excellent): Imidan, Lannate, Provado, Actara, Assail, Calypso, and Belay.

Guest Article: Managing Peach Harvest Qualtiy with ReTain

Win Cowgill, Area Fruit Agent (Reprinted from Rutgers Plant & Pest Advisory, Fruit Edition, July 5, 2011

Retain has had a label for peaches since 2004. It has not been used widely by peach growers but has some specific benefits for PYO and direct market peaches, specifically the ability to manage maturity and fruit firmness. It is also labeled on plum, prune and apricot. NJ growers have used it to help reduce premature fruit drop in late (September) ripening cultivars.

New Jersey growers must focus harvest management strategies for optimum fruit quality. Consumer demand, market demand, storage requirements and labor availability all influence harvest decisions. Retain can be a tool for peach growers to manage peaches. Retain has been evaluated on multiple peach varieties over multiple years. In general ReTain is a harvest management tool that slows the fruit maturation process.

ReTain works by retarding the development of ethylene, the chemical that causes ripening. The active ingredient is a natural occurring product aminoethoxyvinylglycine (AVG), which is produced by fermentation. The fermentation process required to produce AVG is very difficult and very expensive. Because of this, ReTain should only be used in high value varieties with a large crop of unblemished fruit.

Benefits on Peach include:

  • Allow you to let peaches hang on the tree longer, allowing greater color development.
  • Allow you to stager harvest of a particular variety if needed, delaying harvest up to four days
  • Increased fruit firmness at harvest across most varieties tested allowing you to pick more mature fruit that is still firm when handled
  • Increased fruit firmness in cold storage over several weeks time

Retain works slightly different on each variety; you will need to evaluate it on a variety-by-variety basis. On a few cultivars there is very little effect, Redhaven is the most notable example.

ReTain must be applied 7-14 days prior to anticipated harvest to be effective, therefore it is essential growers carefully project ripening dates of each individual block which they plan to use ReTain this season. There is a 7-day PHI on Retain with peaches and nectarines.

Important considerations to follow with ReTain applications on peaches in New Jersey:

  • Use the full rate of ReTain (1 pouch or 333 grams/Acre of formulated product) for peaches and nectarines
  • Apply 7-14 days before normal anticipated harvest. (When harvest would be expected if not treated with Retain.)
  • Use of organosilcone surfactant is not required on stone fruits but may be beneficial.
  • If desired use an organosilcone surfactants such as: Silwet L77 at 6.5-13 fluid ounces per 100 gallons, or Sylguard 309 at 6.5-13 fluid ounces per 100 gallons. When high temperatures prevail, the lower rate of surfactant is recommended.
  • Non ionic surfactants may also be used.
  • ReTain should be applied with a sufficient amount of water to ensure thorough wetting of the fruit and foliage while avoiding spray run-off. Adjust water volume based on tree size and spacing. No alternate row spraying. 100 gallons per acre at 2x has shown to be effective.
  • For optimum results apply during periods of slow drying weather conditions. No rainfall or overhead irrigation should occur within six hours of ReTain application.
  • Do not apply ReTain to trees under stress. They may not respond to the benefits of ReTain.
  • Tank-mixes of ReTain with other agricultural products have not been fully evaluated.

Note: read the label completely to fully understand the use of Retain on stone fruit, there are significant differences in use as compared to apple. If you have specific questions regarding the use of Retain on peaches do not hesitate to contact me <> or Jon Clements <

Useful links

UMass Extension Fruit Program

UMass Cold Spring Orchard

Scaffolds Fruit Journal

Follow me on Twitter and Facebook