Northern Michigan FRUITNET'99
August 19, 1999
Cooler temperatures this past week have slowed evaporation and degree day accumulation. Evaporation the past week was 1.06", with total evaporation for August of 3.04". Rainfall at the NWMHRS during the week of 8/10-8/17 was 0.3", but a trace or more precipitation was recorded on 6 of the 7 days. Since August 1, 1.26" of rain has fallen, with only 6 of the first 19 days recording no precipitation.
GROWING DEGREE DAYS
Codling Moth – Trap catches were down this week at the Station and at the abandoned orchard. Growers should continue to monitor for flight though. Last year adult flight peaked at the end of August, long after the peak should have occurred.
Apple Maggot – Adults continue to emerge and infest commercial blocks. Adult emergence has slowed in the abandoned block we monitor.
Potato Leafhoppers continue to be active in unsprayed blocks. Plums, apples and strawberries are most susceptible. This year they have also infested sweet cherries to some degree.
Green Apple Aphids have slowed way down now that the terminal buds have set.
Mites – Two spotted spider mites have not built up to the high numbers in tart cherries that they have in the last few years, although there are scattered blocks with levels above threshold. Adequate moisture in the groundcover keeps them from migrating into the trees. At the Station, European red mites have built up higher than in recent years in tarts, although still fairly low. At this time it is too late to justify any treatment for mites in tart cherries. The two spotted spider mites will start to migrate out of the trees in about two weeks. Apples may require a miticide if above threshold. The European red mites will lay their eggs in the calyx end of the apples if populations are very high. Pyramite is the best adulticide for European red mites that is available.
Spotted Tentiform Leafminer – Tissue feeding mines continue to show up. Trap catches are up this past week, so growers will likely see more mines showing up. If fruit size is critical, then a Provado spray may be worth the extra money, even this late in the year. This would more likely be worthwhile on late season varieties. Provado will also control the white apple leafhoppers.
Cherry Leaf Spot continues to show up in many orchards. The worst orchards are now defoliated. Most orchards, with only one post harvest spray, are now likely to be unprotected from further infections from leaf spot. Young trees, in particular, may benefit from another Bravo application. Leaf spot has also shown up in plums this year. Growers should check their plum blocks and if present, treat with Benlate/Captan.
Sooty Blotch/Flyspeck – The sooty blotch fungus can be found on abandoned apples. Growers of fresh market apples should apply a Benlate/Captan or Topsin M/Captan spray as soon as possible, if fungicides have not been applied in July and August.
Fireblight – If fireblight has spread further in young orchards and if it is not too advanced, it can be cut out now.
Brown Rot – Plums should be watched closely. As harvest nears, they become much more susceptible to brown rot. Peaches, that have not been harvested, should have fungicide protection against brown rot, particularly if shelf life is required.
Apple Maturity Program
Once again, we will be conducting an apple maturity program at the NWMHRS this fall. We will be running starch iodine, pressure tests and some brix tests. If you have apples that you would like tested, feel free to drop them off at the Station. Gary Thornton will be collecting samples as well, so if you let me know, I may be able to pick them up.
The data that we obtain will
then go out via this FruitNet, as well as being available on the Pome
Fruit code-a-phone – 947-3063.
NW Michigan Horticultural
Growing Degree Day Accumulations for July 26 - Aug.19, 1999
The harvest is complete. Oregon, Utah and Washington finished their harvests this week.
Total production was 251.4 million pounds. Production from normally regulated districts was 215 million pounds. Total production is about 10 million pounds less than the USDA estimated in June. Please recall, that the USDA revised Penn.'s estimate from 9 to 5.5 million pounds. This reduced the total USDA estimate to 256.2 million pounds.
It was good to have a smaller crop this season. The Board will meet Sept. 9 & 10, 1999 to set the final percentage.
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