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Healthy Fruit 2011 Vol. 19:15

Jul 19, 2011

Current (through July 18) degree day (DD) Accumulations

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

Base 43: 1972

Base 50: 1388

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

Apple maggot 1st oviposition punctures: 1605-2157

Apple maggot flight peak: 2104-2542

Codling moth 2nd flight begins: 1569-2259

Codling moth 2nd flight peak: 1931-2735

Lesser apple worm 2nd flight begins: 1418-2002

Oriental fruit moth 2nd flight peak: 1455-1995

Oriental fruit moth 2nd flight subsides: 2049-2515

Redbanded leafroller 2nd flight peak: 1546-1978

Redbanded leafroller 2nd flight subsides: 2192-2668

STLM 2nd gen. tissue feeders present: 1378-2035

Spotted tentiform leafminer 2nd flight subsides: 1977-2371

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) 2nd generation 7% CM egg hatch: July 24, Sunday, = target date for 1st spray where multiple sprays needed to control 2nd generation CM (if needed and allowed by pre-harvest interval). 2nd generation 30% CM egg hatch: August 2, Tuesday, = target date where one spray needed to control 2nd generation CM.
  • Spotted Tentiform Leafminer (STLM): Third optimized sample date for 2nd generation STLM sapfeeding mines, if needed: July 24, Sunday.
  • 2nd generation White Apple Leafhopper (WAL) found on apple foliage: August 1, Monday.
  • 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: July 29, Friday.

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

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

I am no entomologist, but if you examine the list of insect pests above under 'Significant upcoming orchard insect events based on degree days (Base 43),' there seems to be a lot of potential activity right now. I think we sometimes get in trouble this time of year -- particularly with the lepidopteran pests like codling moth and leafroller(s) -- by ignoring it. Spotted tentiform leafminer (STLM) warrants keeping an eye on too in some orchards. So, if you have a history of any of these pests in your orchard, you should consider scouting and treatment if warranted. Consult the New England Tree Fruit Management Guide for specific chemical treatments for each pest.

Japanese beetles are still around but don't seem to be doing a lot of concentrated damage (yet). Again, control options 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).

Other than that, in apples, continued summer disease management and calcium sprays should be ongoing. Summer disease sprays can be stretched out in dry weather of course.

As peaches ripen, controlling brown rot will be mandatory if we get any rain. Because of the wet spring, there is probably a lot of 'dormant' brown rot fungus out there just waiting to get a foothold.

Finally, now is a good time to start collecting leaves if you need to leaf analyses. We recommend doing your block(s) of tree fruit every 3 years. Form and details attached, as well as following article from Michigan State University.


Guest Article: Mid-summer leaf samples for nutrient analysis

Reprinted from Michigan State University Extension News for Agriculture, Fruit

Now is the time to collect leaf samples for nutrient analysis, which is the best way to assess the nutritional health of perennial fruit plantings.

Eric Hanson, Michigan State University Extension, Department of Horticulture

As shoots grow and leaves age, nutrient concentrations change. Mid-summer is the standard time to sample because levels of most nutrients are relatively stable and are most easy to interpret by comparing them to known values. Sampling tissues at other times can also be useful to diagnose specific problems. In this case, samples from affected and healthy plants are needed for comparison since desired values at non-standard sampling times are less well-defined.

Many growers rely too heavily on soil testing to guide fertilization practices. Although soil tests provide a useful measure of pH, soil phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) levels are often misleading because they do not closely reflect levels in perennial fruit plants. This may be due to several factors, but the bottom line is that basing fertilizer choices on soil nutrient levels only is inadequate. Most importantly, there is no effective means of monitoring soil nitrogen (N) availability to perennial crops, so soil tests are of no value in guiding fertilization decisions for this key nutrient.

Leaf analyses can be used to diagnose nutritional problems and to identify developing problems before growth or yield is affected. Sample young plantings every one to two years and established plantings every two to three years. The whole farm can be sampled in the same years, or portions sampled more frequently.

Define sampling units. Divide the farm into sampling units or areas that have uniform soil types, management history and variety. Farms with variable soils or history will require more sampling units to provide an accurate picture of the nutritional health. If the farm is very uniform, with large blocks of the same age and varieties, units can be as large as 15 acres.

Sampling. Sample leaves in late July to early August. Collect at least 50 leaves from different plants throughout the sampling unit. Select healthy leaves from the middle of this year's shoots. If the leaves are dusty, rinse briefly in tap water and lay leaves out on a table top until they are dry to the touch. For vineyards, only the petioles, or leaf stems, are collected.

Submitting samples. Package leaves in clearly labeled paper bags and send them to a reputable laboratory.

Diagnosing nutritional problems. If you wish to diagnose a suspected nutritional problem, collect one sample from plants beginning to develop symptoms of the problem and a second from nearby healthy plants. These samples can be collected at anytime during the season.

The total cost tissue analysis (sampling labor, postage, laboratory fees) can be as high as $40. However, if the sample represents 10 acres, per acre cost is $4. This small input can readily be covered if results show that fertilizer rates can be reduced. Test costs are incidental if fruit yields or quality are improved due to fertilization changes.

Ed. note: some labs offering tissue analysis (no endorsement is implied)

UMass Soil and Plant Nutrient Testing Laboratory, West Experiment Station, 682 North Pleasant St., Amherst, MA 01003
A & L Analytical Laboratories, Memphis, TN (800-264-4522)
Spectrum Analytic, Washington Court House, Ohio (800-321-1562)

Useful links

UMass Extension Fruit Program

UMass Cold Spring Orchard

Scaffolds Fruit Journal

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