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Healthy Fruit 2010 Vol. 18:11

Jun 15, 2010

Current (through June 14) degree day (DD) Accumulations

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

  • Base 43: 1145
  • Base 50: 695

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

  • Lesser appleworm 1st flight subsides: 990-1446
  • Obliquebanded leafroller summer larvae hatch: 1038-1460
  • Peachtree borer 1st catch: 779-1347
  • Cherry fruit fly first catch: 755-1289
  • Spotted tentiform leafminer 2nd flight begins: 982-1152
  • Apple maggot 1st catch: 1234-1640

Orchard Radar insect synopsis (for Belchertown)

First dogwood borer (DB) egg hatch roughly: June 15. Peak hatch roughly: July 23

Codling moth (CM) development as of June 15: 1st generation adult emergence at 95% and 1st generation egg hatch at 66%. In most orchards, insecticide targeted against plum curculio and apple maggot prevent codling moth damage. If targeted codling moth control is needed, key management dates are: 1st generation 20% CM egg hatch: June 2, Wednesday (= target date where one spray needed to control 1st generation codling moth)

1st generation Obliquebanded Leafroller (OBLR) flight begins around: May 28, Friday. Where waiting to sample late instar OBLR larvae is not an option (= where OBLR is known to be a problem, and will be managed with insecticide against young larvae): Early egg hatch and optimum date for initial application of B.t., Delegate, SpinTor, Proclaim, Intrepid, Rimon, Altacor, Belt, pyrethroid or other insecticide effective against OBLR (with follow-up applications as needed): June 14, Monday. 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: June 23, Wednesday If first OBLR late instar larvae sample is below threshold, date for confirmation follow-up: June 27, Sunday

2nd generation Oriental Fruit Moth (OFM) flight begins around June 19, Sunday; first treatment date, if needed: June 26, Saturday; second treatment date, if needed, July 9, Friday

2nd redbanded leafroller (RBLR) flight begins around June 21, Monday; peak catch and approximate start of egg hatch, June 28

The way I see it

I have run two models for predicting harvest dates of McIntosh apples and Redhaven peaches. The Cornell model for Mac apples is based on bloom date and the average temperature during the 30 days after bloom. Bloom was so early in Belchertown this year (April 24) the model had to be 'modified' a bit to work -- in essence I used May 1 as full bloom. The model predicts the LAST day when Mac apples can be picked for CA harvest, which this year turns out to be September 13. More normal years run about a week later, so you can see we are easily on track for a one-week-earlier than average harvest of McIntosh apples.

For Redhaven peaches, the model comes from Bill Shane at Michigan State University. I am not sure we have good Redhaven harvest records, but the model predicts July 30 as the estimated harvest date in Belchertown. (The model is based on degree-days base 50 from Jan-1 to Jun-3.) Again, that is a good 7-10 days ahead of when I perceive average Redhaven harvest to be. Redhaven is regarded as more-or-less middle of the peach harvest season.

Othwerwise, on the disease front, most growers should have started fungicide sprays for apple summer disease control this week at the latest based on accumulation of leaf wetness hours since petal fall. Fungicide options in a include: Adament, Indar, Captan + Topsin-M (or generic), EBDC fungicide (watch pre-harvest interval) + Topsin-M, Captan + phosphite fungicide, or Ziram. See the 2010 New England Tree Fruit Management Guide for rates and details.

And on the insect front, I would be on the lookout for potato leafhopper as they are likely to be early this year, and about now is the time to treat for hatching-out obliquebanded leafroller with the 'best' insecticides Delegate, Altacor, or Intrepid. I have included the article on apple maggot from this week's Scaffolds Fruit Journal below.

JC

WANTED: Dogwood borers, Peachtree borers, Round- or Flat-headed Apple borers, or other boring insects.

We are doing biocontrol of Emerald Ash Borer (EAB), a beetle from China that has already killed 10's of millions of ash trees in the Midwest and has spread to 13 states, including NY. We have already tested and released three parasitic wasps from China for biocontrol, but we will be getting a new parasitic wasp from Russia in a few weeks. We need to conduct safety tests to ensure that if we release this species it will only attack the EAB and not other native borers. To do that, we need to find and rear native borers. Would you please help us and give us a call if your orchard is infested with boring insects (we can collect either adults or mature larvae). We would be happy to take them off your hands and put them to good use. Please contact Tracy Ayer (ext. 248) or Juli Gould (ext. 220) at 508-563-9303 or send us an email at jennifer.ayer@aphis.usda.gov or juli.r.gould@aphis.usda.gov. Thank you in advance.

Juli Gould, Entomologist

USDA-APHIS-PPQ

Buzzards Bay, MA

Guest article—Return of the Fly

Art Agnello and Harvey Reissig, Cornell/Geneva NY

reprinted from Scaffolds Fruit Journal, Vol. 19, No. 13, June 14, 2010

It is once again the time we anticipate the first appearance of apple maggot (AM) flies in wild apple trees and abandoned orchards, particularly in eastern N.Y.; western N.Y. could be about a week later (or not, depending on what kind of temperatures we get over the next week or so). Crop scouts and consultants have been using traps to monitor AM populations for a long time, but this tactic, useful as it is, nevertheless is not recommended in all cases. Some orchards have such high or such low AM populations that monitoring for them is not time-efficient. That is, in some blocks, sprays are needed predictably every season, and on a calendar basis; conversely, they are rarely needed at all in other blocks. However, most commercial N.Y. orchards have moderate or variable pressure from this pest, so monitoring to determine when damaging numbers of them are present can reduce the number of sprays used in the summer with no decrease in fruit quality.

Sticky yellow panels have been in use for over 40 years, and can be very helpful in determining when AM flies are present. These insects emerge from their hibernation sites in the soil from mid- June to early July in New York, and spend the first 7–10 days of their adult life feeding on substances such as aphid honeydew until they are sexually mature. Because honeydew is most likely to be found on foliage, and because the flies see the yellow panel as a "super leaf", they are naturally attracted to it during this early adult stage. A few of these panels hung in an orchard can serve as an early warning device for growers if there is a likely AM emergence site nearby.

Many flies pass this period outside of the orchard, however, and then begin searching for fruit only when they are ready to mate and lay eggs. That means that growers don't always have the advantage of this advance warning, in which case the catch of a single (sexually mature) fly indicates that a spray is necessary immediately to adequately protect the fruit. This can translate into an undesirable risk if the traps are not being checked daily and produce an immediate response, something that's not always possible during a busy summer.

To regain this time advantage, researchers have developed traps that have the form of a "super apple"— large, round, deep red, and often accompanied by the smell of a ripe apple — in an attempt to catch that first AM fly in the orchard. Because this kind of trap is so much more efficient at detecting AM flies when they are still at relatively low levels in the orchard, the traps can usually be checked twice a week to allow a 1–2-day response period (before spraying) after a catch is recorded, without incurring any risk to the fruit. In fact, research done in Geneva over a number of years indicates that some of these traps work so well, it is possible to use a higher threshold than the old "one fly and spray" guidelines recommended for the panel traps. Specifically, it has been found that sphere type traps baited with a lure that emits apple volatiles attract AM flies so efficiently that an insecticide cover spray is not required until a threshold of 5 flies per trap is reached.

The recommended practice is to hang three volatile-baited sphere traps in a 10- to 15-acre orchard, on the outside row facing the most probable direction of AM migration (towards woods or abandoned apple trees, or else towards the south). Then, periodically check the traps to get a total number of flies caught; divide this by 3 to get the average catch per trap, and spray when the result is 5 or more. Be sure you know how to distinguish AM flies from others that will be collected by the inviting-looking sphere. In home apple plantings, these traps can be used to "trap out" local populations of AM flies by attracting any adult female in the tree's vicinity to the sticky surface of the red sphere before it can lay eggs in the fruit. Research done in Massachusetts suggests that this strategy will protect the fruit if one trap is used for every 100–150 apples normally produced by the tree (i.e., a maximum of three to four traps per tree in most cases), a density that makes this strategy fairly impractical on the commercial level.

A variety of traps and lures are currently available from commercial suppliers; among them: permanent sphere traps made of wood or stiff plastic, disposable sphere traps made of flexible plastic, and sphere-plus-panel ("Ladd") traps. The disposable traps are cheaper than the others, of course, but only last one season. Ladd traps are very effective at catching flies, but are harder to keep clean, and performed no better than any other sphere trap in our field tests. Brush-on stickum is available to facilitate trap setup in the orchard. Apple volatile lures are available for use in combination with any of these traps. These tools are available from a number of orchard pest monitoring suppliers, among them:

• Gempler's Inc., 100 Countryside Dr., PO Box 328, Belleville, WI 53508; 1-800-382-8473, Fax,

1-800-551-1128 <http://www.gemplers.com/>

• Great Lakes IPM, 10220 Church Rd. NE, Vestaburg, MI 48891; 800-235-0285, Fax 989-268-5311

mailto:glipm@greatlakesipm.com <http://www.greatlakesipm.com>

• Harmony Farm Supply, 3244 Hwy. 116 N, Sebastopol, CA 95472; 707-823-9125, Fax 707-823-1734 mailto:info@harmonyfarm.com ">www.harmonyfarm.com>

• Ladd Research Industries Inc., 83 Holly Court, Williston, VT 05495; 800-451-3406, Fax 802-660-8859 mailto:sales@laddresearch.com <http://www.laddresearch.com>

• Olson Products Inc., PO Box 1043, Medina, OH 44258; 330-723-3210, Fax 330-723-9977 <http://www.olsonproducts.com/>

• Suterra-Scenturion, 213 SW Columbia, Bend, OR 97702-1013; 866-326-6737, Fax 541-388-3705 <http://www.suterra.com>

By preparing now for the apple maggot season, you can simplify the decisions required to get your apples through the summer in good shape for harvest.

Useful links

UMass Fruit

Scaffolds Fruit Journal

NEWA (Network for Environmental and Weather Applications)

JMCEXTMAN Blog

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