SW Michigan Fruit Update
August 8, 2006
Mark Longstroth
Bill Shane
Weather.
Temperatures over the past week had highs from mid 80s to mid 90s. Rainfall on August 2nd and 3rd totaled 3 to 4 inches, with high temperatures favorable for fruit rot development. The GDD below are from the Michigan State University Enviro-weather (http://www.enviroweather.msu.edu) site.
GDD totals March 1 through August 6 |
|||
| Location | GDD 42 | GDD 45 | GDD 50 |
| SWMREC | 2865 | 2470 | 1887 |
| Lawton | 2932 | 2549 | 1964 |
| Fennville | 2661 | 2294 | 1737 |
General insect
activity
Japanese beetles continue to
emerge. Fruit flies such as cherry fruit fly, apple maggot and blueberry maggot continue
to be out, with generally low numbers for apple maggot. Leafhopper numbers are increasing.
Watch for possible European corn borer flight into fruit orchards as corn fields begin to
dry down.
Tree fruit
Peach varieties being harvested in
Berrien County include final harvests of Red Haven, continued harvests of John Boy,
Starfire, Blazingstar, and first picks of Allstar and PF17. Hot weather has caused
flesh of some varieties to ripen faster closer to the peel than near the pit. Brown
rot is becoming more prevalent on fruit especially where spray programs have been light
and nicks caused by insect and bacterial spot provide entry points for the pathogen.
Fruit size, skin color and quality have been good. Two-spotted mites are at
significant levels in some sites, especially on mite-prone varieties. Western flower thrip
damage (1/2 to 1 inch diameter tan spots on skin) is becoming more widespread with recent
hot, dry weather. Spintor, the most effective material against thrips has a 2 week
preharvest interval. The flight of second generation of Oriental fruit moth has been
steady over the past three weeks. Growers should have protection in place against egg hatch of the second
generation of OFM, which is underway.
Sweet cherry and tart cherry growers need to protect against cherry leaf spot to maintain tree health. Defoliation of tart cherry tree tops due to cherry leaf spot is common in some orchards. Pruning of mature tart and sweet can be done now for trees with good vigor, otherwise wait for the traditional time in the spring. Japanese beetles have been skeletonizing leaves in tops of sweet cherry trees.
Plums coming into harvest now are Burbank and Ozark Premier. Growers should maintain brown rot program for plums close to harvest and watch for potato leafhoppers and deer damage, especially on young trees.
In apples, Oriental fruit moth flight for the second generation has been underway for over a month. Codling moth trap catches have increased over the last 2 weeks for the second generation flight, with egg hatch well underway. Fruit entries from these two are now being reported. Obliquebanded leafroller trap catch has increased for the area, with a biofix for the 2nd generation of approximately August 1. Growers have been treating for European red mites populations which have caused leaf bronzing. Green aphid numbers are increasing. Apple maggots are being trapped but the pinpoint holes that are the sign of egg laying are still rare. Sooty blotch and flyspeck symptoms are being seen but still at low level. Fungicides to reduce sooty blotch and flyspeck should be included in cover sprays. Leaf drop due to scab is common in unsprayed orchards.
Pear fruit should be protected from second-generation codling moth.
Small
fruit
Blueberry harvest of
Bluecrop and now Jersey harvest is underway. Berry size and quality are generally
excellent and price has been holding well. The recent wet weather increases the likelihood
of fruit rots such as anthracnose
and alternaria. Japanese beetle
numbers have stabilized somewhat. Blueberry
maggot flies are still scarce. Growers should be scouting for leaf rollers and tussock moth larvae.
Grapes are past berry touch. Grape berry moth trap catch numbers are up and larvae are feeding in the clusters. Grape leafhoppers are scarce. Phomopsis is easy to find in most plantings. Other diseases such as black rot, powdery mildew and downy mildew are appearing. Grape scouting reports can be found at the MSU grape resources web site: www.grapes.msu.edu.
Raspberry flower clusters are opening appearing on the primocanes of fall bearing varieties. Japanese beetles are still actively feeding.
