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Healthy Fruit 2011 Vol. 19:8

May 24, 2011

Current (through May 23) degree day

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

Base 43: 531

Base 50: 304

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

Spotted tentiform leafminer sap-feeders present: 343-601

Oriental fruit moth 1st flight peak: 350-552

Lesser appleworm 1st catch: 263-567

Lesser peachtree borer 1st catch: 479-685

European red mite 1st summer eggs: 447-555

Codling moth 1st catch: 400-578

Plum curculio oviposition scars present: 485-589

Orchard Radar insect synopsis

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

  • Codling moth (CM), 1st generation, first sustained trap catch biofix date: May 16, Monday. 1st generation adult emergence at 7% and 1st generation egg hatch at 0%.
  • Oriental fruit moth (OFM) 1st generation - 55% egg hatch and first treatment date, if needed: May 29, Sunday.
  • Increased risk of Plum Curculio (PC) damage as McIntosh and similar cultivars increase fruit size: May 20, Friday. Earliest safe date for last PC insecticide spray: May 29, Sunday.
  • Spotted Tentiform Leafminer (STLM): 1st generation sapfeeding mines start showing: May 21, Saturday. Optimum sample date is around Monday, May 23, when a larger portion of the mines are visible.
  • 1st generation White Apple Leafhopper (WAL) found on apple foliage: May 54, Sunday
  • Estimated apple sensitivity to chemical thinners: Increased sensitivity, May 24 (Tuesday); Stronger influence for increased sensitivity, May 25-27 (Wednesday-Friday); Increased sensitivity, May 28 (Saturday); intermediate sensitivity May 29-31 (Sunday-Tuesday.

Upcoming meetings

June 14, 15, 16: Tree fruit twilight meeting, TBA

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

The way I see it

Yesterday I attended a meeting at Fix Brothers Orchards in Hudson, NY sponsored by the Hudson Valley Regional Fruit Program. Topics were disease and insect management presented by David Rosenberger and Peter Jentsch, and nutrient management and fruit thinning presented by Steve Hoying and Terence Robinson. My take-home follows:

Disease management

Apple scab is not done -- wetting periods have been frequent and extended. Scout orchard for primary infections on all foliage for another couple weeks at least before stopping scab sprays, particularly during wet weather. Although primary scab season is not over yet, ascopores will be mature in all MA locations by the end of next week. Inspire Super is probably the best SI fungicide if you need kickback. Particularly if you suspect shift towards resistance. (Need your orchard tested for SI resistance? Contact us for details.) Be careful with Captan as tender foliage makes phytotoxicity more likely, particularly when combined with micro-nutrients such as urea. Be careful.

Powdery mildew conditions are ideal. If you have not included a SI fungicide such as Rally in scab sprays, do it now. Unfortunately, Inspire Super is weak on mildew. Don't forget newly planted trees, spray with fungicide!

Fire blight is a threat, and strep sprays will likely not be wasted if there is any lingering bloom in apple or pear. Copper should be applied to newly planted trees (no fruit) but use low rate. In addition, strep should be applied if these trees are in bloom. (Don't use copper on bearing trees unless you want russet.)

Pear fabraeae leaf spot conditions are ideal. The critical control period is petal fall to July 4. Mancozeb are the (EBDC) fungicides of choice, however Syllit can also be used.

Brown rot blossom blight

European brown rot

European brown rot (EBR), vs. the more common American brown rot (ABR) has been a problem on peaches this year. EBR is not controlled by Bravo at bloom, hence Indar is advised. EBR is more serious than ABR and will re-emerge when fruit ripen if not controlled now. (Ed. note: last week in RI, we saw a serious case of what might be EBR. Grower used Bravo at bloom but that was it. Grower advised to spray Indar a couple times now to halt the spread of this serious infection.)

Bacterial spot of peach and nectarine is infecting now, Mycoshield sprays need to be applied starting now to control or diminish. The best defense against bacterial spot is to avoid planting susceptible cultivars.

Insect management

Insect activity is within a few days of 'average.' Tarnished plant bug and European apple sawfly activity has been minimal to date.

Plum curculio (PC) will be ramping up. Fruit need to be 6-7 mm in size to be attractive. Insecticide options include: Guthion at higher rate (excellent while we have it); Calypso (very good, good OP replacement, has contact, residual, and systemic activity, controls other insects); Imidan (fair to good, does not last as long as Guthion, need to use high rate on PC); Actara (good at high rates, but does not control codling moth); Leverage (very good, pre-mix so might want to save for other problem pests like brown marmorated stink bug if it appears). Do not use Assail for PC, weak on this pest, save for others.

Codling moth (CM) adults should be flying now and caught in pheromone traps. Apply insecticides targeting early egg laying period at 100-200 DD from trap catch. Many insecticides to choose from, including: Alatacor, Assail, Calypso, Delegate, Voliam Xpress, Leverage, Guthion, Imidan, pyrethroids, and Lannate.

Fruit thinining

Apple and pear are under carbohydrate deficit since green tip, however, little stress. (Yet.) When the sun comes out and temperatures warm trees will be under stress (want to grow) and fruit will naturally be sacrificed. Don't panic - watch and wait (late this week, this weekend?) to see what appears to be staying and what appears to be going. When applying chemical thinners, reduce rates by 25 to 50% from what you 'normally' use depending on fruit set and variety. Fruit are predisposed to come off easily this year.

Thanks Dave, Pete, Steve and Terence for sharing your knowledge. And Mike Fargione for sponsoring the meeting.

JC

2011 New England Tree Fruit Management

As a reminder, the 2011 New England Tree Fruit Management Guide is still available for purchase

The 2011 New England Tree Fruit Management Guide (NETFMG) is available NOW. For $50 you will receive the printed guide by postal mail. You can download and print a mail-in form to order the NETFPMG by personal check here.

Note that for 2011 the herbicide/weed control section has been completely revised, and all sections have been carefully reviewed for changes in 2011.

Also note that Commonwealth Quality produce certified growers should have the 2011 NETFMG in their possession to achieve the maximum score!

JC

Updated Trac pesticide recordkeeping software available

Updated for 2011 Trac pesticide recordkeeping software from the New York State IIPM Program for tree fruit (apple, cherry, peach-nectarine, and plum) is now available

It's my opinion TracApple, TracPear, TracCherry, and TracStoneFruit are the best pesticide recordkeeping applictions available, and well worth the purchase price. A single Trac software is $60;
the TracTreeFruit Bundle that includes TracApple, TracPear, TracCherry and TracStoneFruit is $180.

JC

Thinning Suggestions (Mike Fargione)

Michael J. Fargione, Extension Educator
Cornell Cooperative Extension Hudson Valley Regional Fruit Program

Tree Fruit Recorded Message for Tuesday, May 24, 201

Here are my notes from yesterday's field meetings. Steve Hoying and Dr. Terence Robinson indicated that the next 7 days will be the necessary apple chemical thinning window in much of our region. During this period, growers should reduce application of thinning agents below your "normal" rates for the following reasons:

  1. Many blocks, including some perennial heavy-bearing varieties like 'Gala', had moderate to less bloom due to 2 consecutive past years of heavy crops and some winter injury.
  2. Foliage on trees is currently greater than normal for this time of year and very succulent. More leaf area and soft tissue will mean thinning chemicals will be drawn into the plant at greater-than-normal rates.
  3. Predicted warm temperatures over the next week will mean trees will respond more to the thinners.
  4. Trees have been running a carbohydrate deficit since green tip this spring and the deficit is expected to increase this week (see updated carbohydrate models for Marlboro and Hudson). This means that reserves of carbohydrates (i.e. energy source) in the trees are likely to be reduced from "normal" and natural thinning or "June drop" may be greater than normal. (I am already seeing drop in some blocks, but we expect to see significantly greater amounts once the trees undergo some stress with the upcoming heat.

Based on the above observations, apple thinning recommendations for our area include:

  1. Wait as long as possible to thin in the hope you can determine what level of drop will occur naturally and/or the result of your petal fall thinner applications. You can get effective thinning out to about 15mm king fruit size. At least wait until Wednesday or Thursday, as the coming heat will cause fruit to start to differentiate in size and you can get some handle on how much is likely to stay and what will come off in the "June drop".
  2. Reduce "normal" thinner rates by 25% where blocks appear to have had good to snowball bloom and good pollination. Example: if you normally use 10 ppm NAA, drop back to 7.5 ppm. Where blocks appeared to have poor-moderate bloom, reduce rates further and use 50% of the "normal" rate or less. There are some blocks where natural June drop will be sufficient and no chemical thinning may be needed this year.
  3. This might be a year where NAA alone or carbaryl alone are options in blocks of moderately hard-to-thin cultivars (Jersey Mac, Paula Red, Aceymac, Spartan, Stamen) where you would normally combine the two. Given the forecast for repeated wetting this coming week, you might want to choose NAA alone because repeated wetting of carbaryl may lead to excessive thinning.
  4. Consider still using the combination carbaryl plus NAA or Maxcel on hard-to-thin cultivars (examples include Cameo, Gala, Honeycrisp, Fuji, Jonamac, Golden Delicious, Red Delicious, Empire, Lady Apple).
  5. Many growers prefer to use Maxcel instead of NAA on small-fruited cultivars like Gala and Empire. Do not use Maxcel without tank-mixing it with carbaryl as it is too weak a thinner on its own. Just drop the rate of Maxcel by 25-50% depending on the bloom.
  6. Do not concentrate the carbaryl this year to reduce residues and thinning from rewetting. Example: if you have a 500 gallon tank, only put in 1 pint per 100 gal or a total of 5 pints, regardless of the number of "X's" you spray.
  7. This would be a year to use dry powder carbaryl to reduce the greater possibility of phyto associated with the liquid formulations, particularly the XLR+ formula. However, we learned yesterday that the powder is in short supply or not available. Again, this is even more reason not to concentrate the carbaryl.
  8. It may also be wise to leave captan out of your fungicide treatments in your next spray if you are thinning this week with carbaryl, and certainly don't tank mix captan with carbaryl this week.
  9. You may not be able to see the results in time this coming week before you must re-thin if you already applied carbaryl, NAA or the combination at "petal fall". In that case, reduce the rate of NAA or Maxcel to no more than 50% of your normal rate in your next application. Some blocks thinned earlier may not need another thinning application, but we won't know that until we have a few days of heat to stress the trees. Warm night temperatures are the key factor.

The following comments by Dr. Robinson are related to pear thinning:

  1. Recent research at Geneva showed that Maxcel at 4 quarts per acre (in 100 gal of water per acre) provided excellent thinning of Bartlet pears in a "normal year". Half that rate or 2 quarts per acre was the recommended rate for Bosc. Not that 2011 is not a normal season and those rate should be reduce by 25% or more this year. This is an expensive treatment but produces great fruit size.
  2. Carbaryl is not labeled on pears, can cause damage, and should not be used with Maxcel when thinning pears.

Ed. note: Most of above applies to Massachusetts growers, however, always consider the bloom, pollination weather and bee activity, and environmental conditions in your orchard. They may be different from above. If any questions, don't hesitate to call me. JC

Useful links

UMass Extension Fruit Program

UMass Cold Spring Orchard

Scaffolds Fruit Journal

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