SW Michigan Fruit Update
August 21, 2006
Weather
The heat of the summer has past. We have cooled off in the last few weeks. Highs fell from the 90s two weeks ago to the 80s last week. Rain showers moved across the region Friday night. Rain totals were as high as four inches in the south. Most areas received one to two inches the weekend. Topsoils have good moisture away from the lake. Soil temps are in the 70s. Heavy morning dews are common. Heavy dews increase some diseases late in the season. This week’s forecast is for warm weather with highs in the 80s with little chance of thunderstorms until the weekend. In the last week we picked up 160 GDD base 42 and 120 base 50. In the coming week we will pick up about 180 GDD base 42 and 150 base 50. The GDD below are from the Enviroweather site.
Southwest
Michigan Growing Degree Day Totals
|
Grapes, from April 1 |
|||
Location |
GDD 42 |
GDD 45 |
GDD 50 |
GDD 50 |
3275 |
2859 |
2218 |
2188 |
|
3176 |
2766 |
2133 |
2101 |
|
3237 |
2823 |
2183 |
2149 |
|
2994 |
2595 |
1981 |
1956 |
|
3316 |
2894 |
2237 |
2222 |
|
3265 |
2851 |
2226 |
2189 |
|
3028 |
2626 |
2008 |
1992 |
|
General Insect Activity
Japanese beetles numbers are low. Apple maggot flies are out in relatively high numbers. More will emerge after our weekend rain. Trap catches for both oriental fruit moth and codling moth are declining. You can use the Enviroweather site GDD model for some pests if you know its emergence or Biofix at your site.
Tree fruit
Peach harvest continues volume and quality are good. Varieties being harvested include Glowing Star and PF23. We are about half way through the third generation of oriental fruit moth. Trap numbers vary quite a bit in area orchards. Egg hatch of the third generation of OFM should end about 3260 GDD base 45 at SWMREC. Brown rot has been a problem for some growers.
Sweet cherry and tart cherry orchards generally look good. Some are suffering from cherry leaf spot, the leaf yellowing and leaf drop is apparent from the road.
In Plums, harvest of early European varieties has begun. Plum pox was detected in a plum planting at SWMREC. See the special plum pox edition of the Fruit CAT Alert.
In Apples, Paula Red harvest has begun. Zestar and Ginger Gold are also being harvested. Apple maggot fly trap catches have increased. The third generations of oriental fruit moth and codling moth are out. Trap catches for these two pests are low. Egg hatch for the second generation of codling moth should end in about 2 weeks at about 2425 GDD base 50 at SWMREC. Sooty blotch and flyspeck is appearing in unsprayed orchards.
Pear harvest has begun. Bartlett pears are being harvested for processing.
Small fruit
Blueberry harvest continues. Elliot harvest is underway. Quality is generally excellent. Clean up harvests of Jersey and other varieties are still occurring. Berry size and quality are falling off in these fields. Alternaria is the most common fruit rot at this time. Blueberry maggot flies are high in some fields. Recent rains should bring these flies out.
In Grapes, veraison has begun. Grape berry moth trap catch numbers are up and larvae are feeding in the clusters. Grape leafhoppers numbers are increasing scarce. It is too late in the season to treat diseases such as phomopsis and black rot. The heavy dews each morning are excellent conditions for downy mildew; this disease is widespread and common. Heavy morning dews will cause this disease to spread quickly. Growers who plan on harvesting should treat. See the article in this week’s Fruit CAT Alert. 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 and leaf spot are common in many fields.
Fall Raspberry harvest has begun. Growers should be scouting for Japanese beetles. Monitor pre harvest intervals (PHI) for fungicide and insecticide sprays. Heavy morning dews are common and this increases the likelihood of gray mold.
