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Healthy Fruit 2010 Vol. 18:8

May 25, 2010

Current (through May 24) degree day (DD) Accumulations

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

  • Base 43: 750
  • Base 50: 423

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

  • Lesser appleworm 1st flight peak: 355-773
  • Codling moth 1st flight peak: 574-1008
  • Plum curculio oviposition scars present: 485-589+
  • Pear psylla summer adults present: 737-885
  • Redbanded leafroller 1st flight subsides: 574-882
  • Obliquebanded leafroller pupae present: 601-821
  • European red mite summer egg hatch: 737-923
  • Peachtree borer 1st catch: 779-1347
  • Cherry fruit fly first catch: 755-1289

Orchard Radar insect synopsis (for Belchertown)

  • Codling moth (CM) development as of May 25: 1st generation adult emergence at 45% and 1st generation egg hatch at 1%. In most orchards, insecticide targetted against plum curculio and apple maggot prevent codling moth damage.
  • 1st generation Obliquebanded Leafroller (OBLR) flight begins around: May 28, Friday
  • Increased risk of Plum Curculio (PC) damage as McIntosh and similar cultivars increase fruit size:
    May 5, Wednesday. Earliest safe date for last PC insecticide spray: May 18, Tuesday
  • 2nd generation adult Spotted Tentiform Leafminer (STLM) begins around June 4, Friday

The way I see it

Notable recent activities:

  • evaluating frost/freeze damage to apple fruit by on-site visits and digital pictures; if you cut open an apple fruit and it is at all brown inside, it is freeze-damaged and will soon fall off; have also seen some external cracks and other defects (frost rings) to developing fruit; varies widely by orchard and within orchard; stone fruit showing lighter and lighter crop as time goes on, but depends...
  • fine-pruning peaches, removing weak and dead wood; this, after an initial round of heavier pruning; will reduce crop load some, which is good (unless there is freeze damage)
  • putting up codling moth (a little late) and oblique-banded leafroller pheromone traps to monitor and set biofix
  • pruning apple root suckers and evaluating for dogwood borer infestation; consider applying directed trunk spray of chlorpyriphos (Lorsban, generic formulations), do not contact apple foliage
  • last of herbicide application using Rely (apple only) or Roundup, Chateau, and Prowl H2O
  • applying Ethrel "rescue" thinning treatments
  • installing irrigation and watering newly planted trees -- very important to get water on trees planted this year as it is turning quite dry
  • planting (late!) Asian Pear variety trial


2010 New England Tree Fruit Management Guide still available

As a reminder, the 2010 New England Tree Fruit Management Guide is still available for purchase

Massachusetts airports on NEWA

Through a cooperative effort with the New York State IPM Program, and the Northeast Regional Climate Center, Massachusetts airport locations have been added to the NEWA (Network for Environmental and Weather Applications) website. (Note that the map is draggable to the left wherein the Massachusetts airport locations are revealed on the map. You can also choose a location from the drop-down list.) Pests forecasts, typically based on temperature, precipitation, and relative humidity are available for various crops (fruit and vegetable). For apples, available forecasts include: codling moth, Oriental fruit moth, obliquebanded leafroller, plum curculio, spotted tentiform leafminer, apple maggot, apple scab, and fire blight.

For more information on how to use NEWA, see 'Pest Forecasts in Real Time -- NEWA' in the April 19, 2010 issue of Scaffolds. I urge you to look at the NEWA website and give us your feedback. This is the future of IPM information delivery! JC

Pest watch

  • fireblight might be of concern still if you have bloom on newly planted apple or pear orchards; a streptomyin spray is warranted if it gets at all wet (rain or heavy dew) on these young trees with bloom; streptomycin should NOT be sprayed on orchards where bloom is past UNLESS there is active (observed) fireblight of shoots or spurs AND you have a significant trauma event (hail, wind-driven rain); you should be scouting for fire blight strikes that will be showing up now from the significant bloom-time fireblight infection event
  • plum curculio will be active with this weather, however, if you sprayed recently, that should be the last spray against curculio you will need this year -- in Belchertown we have accumulated 245 out of the 308 degree days (base 50 from petal fall) that indicate when the last protection for plum curculio will be needed; best non-organophosphate options for controlling plum curculio include Avaunt (6 oz/acre), Actara (5 oz/acre), Assail (6-8 oz/acre), and Calypso (4-8 oz/acre)
  • peach and nectarine fruit are susceptible to tarnished plant bug (or other plant bug) injury, particularly if you mow the orchard or adjacent fields (see picture below); Imidan is NOT particularly effective on plant bug; pyrethroids (Ambush, Pounce, Asana) are excellent for contolling plant bug, OR you could use Actara, Assail, Beleaf, or Leverage (all excellent except for Beleaf which is good); the latter insecticides are better for preserving beneficial insects while the pyrethroids are hard on mite predators

Hort notes

  • Ethephon (Ethrel) can be used for "rescue" thinning when fruit reach 15-25 mm in size. See the fact sheet 'F-129R Late-season "Rescue" Thinning with Ethephon' for application rates and details
  • As soon as new growth exceeds a couple inches, newly planted trees should have their leaders 'stripped' to focus growth into the leader; see 'Training Techniques for Young Apple Trees'
  • Install and turn on irrigation ASAP after planting young trees; the root system is not established enough yet to support the flush of growth these trees are putting out; also, just-planted trees need a good soaking to get the settled and so their is no air contact with roots; thereafter, my recommendation for trickle irrigation is each (dwarf) tree should get 15 gallons of water per week -- so, if you have 3 ft. tree spacing, and are using 0.6 gph emitters spaced at 3 ft., and you leave the water on for 24 hours one time a week, each tree is getting 14.4 gallons of water (0.6 X 24) per week. Of course that regimen can be modified somewhat.

Guest article

Now Sesiid Here (perfectly clear-wing)

by Art Agnello, Entomology, Geneva NY. Reprinted from Scaffolds Fruit Journal, Vol. 9, No. 10, May 24, 2010.

Plant bug injury to peachIn NY, there are two species of sesiid moths that attack peaches — the peachtree borer (PTB), Synanthedon exitiosa, and the lesser peachtree borer (LPTB), S. pictipes. The adult borers are striking clear-winged moths with yellow and steel-blue body markings. The adults of these insects have from one to four yellow-orange stripes across the abdomen, depending upon species and sex. The PTB enters the tree near soil level and does not require the presence of wounds or breaks in the bark for entry, but the LPTB nearly always enters the tree at a pruning scar, canker, mechanical injury, or winter-injured area. The LPTB additionally attacks cherries, causing the same type of injury in the upper trunk and scaf- fold branches of these trees. Both species pass the winter as borers inside the tree, and in the spring emerge as moths that lay eggs on or in the trunk during the summer. The LPTB moth emerges first, normally in late May (although we caught our first of this season a couple of weeks ago), and the PTB doesn't show up until mid-June; both stay active
(laying eggs) through August. When the borer stages hatch, the PTB tends to crawl down the tree to soil level and burrow in there, but the LPTB will move to the nearest injured area, which may be on the lower trunk or just as easily up in the scaffold limbs. LPTB completes its development in one year, but some PTB larvae take two years to develop, so any control measure a grower would elect will require repeating for at least 2–3 years.

Injury is caused by larval feeding on the cambium and inner bark of the trunk close to the soil level (PTB) or on the upper trunk and lower scaffold branches (LPTB). Occasionally, larger roots are also attacked by PTB. Areas attacked often have masses of gum, mixed with frass, exuding from the bark. All ages of trees are injured.

Young trees are at times completely girdled and subsequently die. Older trees are often so severely injured that their vitality is lowered and they are rendered especially susceptible to attack by other insects or by diseases. Although both species may be found in infested trees, younger plantings and those not afflicted by extensive cankers or other bark splits are attacked primarily by PTB.

Control is difficult, owing to the concealed habit of the larvae. Growers have traditionally relied on one or more coarse insecticide sprays (e.g., Asana, Lorsban, Proaxis, Thionex, Warrior) of the trunks and lower scaffold branches to deter egg laying and kill newly established larvae. Because this is a labor-intensive measure that often fails to completely control these pests, many growers choose not to elect treatment, or else do an incomplete job, with the intention of getting what they can out of a planting until infestations combine with other peach production factors to warrant tree removal. However, there is a good alternative in the form of pheromone mating disruption (MD) tools for the control of these perennial pests.

Isomate-PTB Dual (Pacific Biocontrol/CBC America, EPA Reg. No: 53575-34) is a new twist-tie pheromone dispenser labeled for use against both of these species in all NYS stone fruits. They are placed in the trees at a rate of 150-250 ties/Aat or before the first flight, with the higher rate (250/A) recommended when pest pressure is high. This product replaces the Isomate-LPTB formullation. We have conducted trials on the efficacy of Isomate-LPTB with and without the addition of directed trunk sprays in peaches, and after 2 years we saw that the pheromone dispensers completely suppressed trap catches of both PTB and LPTB for both seasons, compared with relatively heavy flights noted in the non-disrupted comparison blocks, showing that pheromone treatment was highly successful in disrupting the chemical communication of males and females of these two species.

These trials provided sufficient evidence that mating disruption alone is able to provide adequate protection from borer infestations in commercial orchards, giving growers an effective non-chemical alternative to trunk sprays for managing this pest complex in their stone fruit plantings. Growers interested in this approach should be placing the pheromone ties during these next 1-2 weeks, before the LPTB flight gets solidly under way statewide.

Useful links

UMass Extension Fruit Program

UMass Cold Spring Orchard

Scaffolds Fruit Journal

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