SW Michigan Fruit Update
July 25, 2006
Weather
Last week cooled off. Highs fell from the 90s two weeks ago to the last week. Rain and strong thunderstorms moved across the region several times. Topsoils are dry near the lake but with good moisture away from the lake. Soil temps are in the 70s. This week’s forecast is for warm weather with highs in the 70s and chance of thunderstorms, with a cooler weekend. The GDD below are from the Enviroweather site.
In the last week we picked up 260 GDD base 42, 240 base 45 and 200 base 50. In the coming week we will pick up 200 GDD base 42, 175 base 45 and 130 base 50.
Southwest
Michigan Growing Degree Day Totals
|
Grapes, from April 1 |
|||
Location |
GDD 42 |
GDD 45 |
GDD 50 |
GDD 50 |
2148 |
1826 |
1347 |
1315 |
|
2223 |
1903 |
1424 |
1383 |
|
1971 |
1662 |
1210 |
1182 |
|
Bill, these are last week’s numbers. Add this week's to total and correct for grape. I have made a bunch of changes below so you need to crosscheck with last week. None of the GDD info below is updated.
General Insect Activity
Japanese beetles numbers have increased. Fruit flies such as cherry fruit fly, apple maggot and blueberry maggot are out in generally low numbers. More will emerge after our rain. The second generation of oriental fruit moth is out. Codling moth trap catches are low but the second generation flight should begin this week or next. You can use the Enviroweather site GDD model for some pests if you know its emergence or Biofix at your site.
Tree fruit
Apricots are still being harvested.
Peach fruit are coloring. Garnett Beauties and other early peaches are being harvested. Split pits are common. Recent rains have caused quality to suffer. Skin cracking and brown rot are increasing. The second generation of oriental fruit moth is out. Trap numbers are up sharply this week. Egg hatch of the second generation of OFM should begin this week. Egg hatch in Southern Berrien County has probably already begun. Biofix in Northern Berrien County for the second generation was probably about July 7 at 1540 GDD base 45. First egg hatch in Southern Berrien County for the second generation was predicted to be June 29 at 1330 GDD base 45. Growers should protect against brown rot. This disease was a problem in sweet cherries.
Sweet cherry and tart cherry harvests have ended. Growers need to protect against cherry leaf spot after harvest.
Plumsare coloring.
In Apples, Oriental fruit moth trap catches are up signaling the beginning of the second generation. Codling moth trap catches are low and the first generation flight should be over. We expect the second generation to emerge this week, and egg hatch to begin at about 1250 GDD past Biofix or about 1578 GDD base 50. We are at 1380 GDD now and 1580 GDD is about 10 days away, about July 27. Obliquebanded leafroller egg hatch is ending. OBLR Biofix was June 12 at 1150 GDD base 42 and egg hatch should end 1000 GDD after Biofix (2150 GDD base 42). European red mites populations have exploded in some orchards and bronzing can be seen. Five to seven mites per leaf is the treatment threshold for European red mite in July. Aphid numbers are increasing. Apple maggots are being trapped. Fungicides to reduce sooty blotch and flyspeck should be included in cover sprays. Leaf drop due to scab in common in unsprayed orchards. Fire blight shoot strike symptoms are reported to be less in orchards treated with Provado. Shoot strike is when the bacteria are carried from infected shoots to healthy shoots by leafhoppers.
Pear fruit are attacked by second-generation codling moth.
Small fruit
Blueberry harvest continues. Bluecrop harvest is underway. Berry size and quality are generally excellent. This wet weather increases the likelihood of fruit rots such as anthracnose and alternaria. Japanese beetle numbers are increasing. Blueberry maggot flies are still scarce. Recent rains should bring these flies out. Growers should be scouting for leaf rollers and tussock moth larvae.
In Grapes are at or past berry touch. Grape berry moth trap catch numbers are up and larvae are feeding in the clusters. Applications to control this pest timed for the end of July are recommended to growers who have not been trapping and scouting due to the light crop. Many growers are reconsidering harvest. This would be a good time to determine your potential yield by harvesting ten vines or one tenth of the vineyard. We recently passed 1200 GDD from April 1 where berries are 50% of harvest weight. Since most of this year’s crop is from secondary buds we are still probably close to 50% for this years berries. 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 recourses page at www.grapes.msu.edu.
Strawberry new growth is off to a good start. Potato leafhopper burn is common in many fields and growers need to treat for this pest to prevent stunting of the new growth.
Raspberry harvest is slowing. Growers should be scouting for Japanese beetles. Monitor pre harvest intervals (PHI) for fungicide and insecticide sprays. Flower clusters are appearing on the primocanes of fall bearing varieties.
Cranberry bloom is ending and post bloom sprays to prevent fruit rots should be applied.
Miscellaneous
Viticulture Day is July 26 at the SWREC.
