SW Michigan Fruit Update

Check the Index for earlier postings

May 31, 2005

Mark Longstroth
Bill Shane
Al Gaus

Meetings

There will be prebloom Grape IPM meetings on Thursday June 2 in Berrien and Van Buren Counties. The Van Buren Meeting is at 10 AM, at the Cronenwett Farm, east of Lawton and the Berrien County Meeting is at SWMREC at 2 PM. There will be one MDA restricted use pesticide recertification credit available at this grape IPM meeting.

The next Monday Update meeting will be, Monday June 6, at the Fruit Acres Farm in Berrien County at 5 PM. There will be one MDA restricted use pesticide recertification credit available at this meeting.

There are several Blueberry meetings planned for June 15 and June 22.

Weather

Last week was pleasant with highs in upper 60s and lows in the 40s. Rain fell as scattered showers on several days. The rain event on May 27^th was not generally an infection event for most diseases. Precipitation totals for last week were one to two tenths of an inch. Topsoils are drying. Soil temperatures are about 65. This week’s forecast is for warmer weather with highs rising into the 70s and then up to 80. There is a good chance of rain as thunderstorms on the weekend.

Southwest Michigan Growing Degree Day Totals March 1 through May 29, 2005				Grapes April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
SWMREC:	770	617	405	383
Bainbridge:	800	645	429	406
Hartford:	720	572	370	351
Grand Junction:	817	663	447	422
Fennville:	675	536	341	321

Tree fruit

Insect activity increased despite the cool evening temperatures.  Plum curculio egg laying scars have been found. Growers should apply protectant materials. We expect to see to see a lot of plum curculio egg laying this week in all fruits. See the notes on plum curculio monitoring in May 3, 2005 Fruit CAT Alert.

Apricot fruits are about an inch in diameter.

Peach fruit are 16 mm in diameter and June drop is underway. The crop is looking very thin in some areas. Oriental fruit moths are laying eggs. Biofix for the first flight was April 15 in Southern and Central Berrien County at 175 GDD base 45, we are now at 617 GDD, 442 GDD past Biofix. Oriental fruit moth egg hatch has begun in Berrien County. For the rest of the region, Oriental fruit moth Biofix was May 6 at 320 GDD base 45 and we are about 400 GDD past Biofix. The expected end of Oriental Fruit Moth egg hatch is at 650 GDD after biofix. Tarnished plant bug feeding scars have been found on young fruit. Plum curculio should be attacking peaches with the warm weather.

Cherries: Sweet Cherries are about 14 mm in diameter. June drop continues. Tart Cherries are 12 mm in diameter and at the beginning of pit hardening. Leaf symptoms of bacterial canker were found in both tart and sweet cherries. Fruit symptoms were found on sweet cherry fruit. Cherry leaf spot symptoms were also found in sweet cherry. Growers should treat for plum curculio if they have not already done so. 

Plums are 16 mm in diameter. Smaller fruit are falling. More fresh plum curculio egg laying scars were found in plums near Paw Paw. 

Apple fruit are generally 14 to 18 mm in diameter. Frost rings can be found on some of the larger fruit.  There has been little response to thinners applied two weeks ago, because of the cool temperatures. Growers should reapply thinners in this warm weather at higher rates of thinning materials. This will be the last good thinning window. Many fruit are already too large for easy thinning. The warm temperatures forecast should make thinners effective this week. The warm temperatures will also increase the natural drop we are seeing.

Oozing fire blight cankers and collapsing shoots and spurs have been found in several orchards on trees infected last year. It is still too early for blossom blight infections symptoms to be visible. Few new apple leaf scab symptoms were found. Symptoms from the May 13-14 infection should be showing up now. We are at the end of primary scab. Scab symptoms from the May 22 infection should appear by June 5. If scab lesions are found in the orchard, growers should continue to apply protectant materials to suppress fruit scab. Growers need to protect the fruit from plum curculio.  European red mites are scarce. Redbanded leafroller trap catches are low. Spotted tentiform leafminer eggs are hatching and growers should scout for sap feeders and mines. Obliquebanded leafroller larvae have been reported in several orchards these larvae will pupate soon, so there is no need to apply materials targeted specifically for this pest. Codling moth trap catches increased dramatically this week. We biofixed for codling moth on May 20 at 334 GDD base 50. We are now at 405 GDDs, 70 GDD past biofix. Traditional materials are applied at about 250 GDD after biofix, but some new materials need to be applied as early as 100 GDD past Biofix. This means these early treatments should go on early this week. Check the article in last week’s Fruit CAT Alert, which includes information on timing. The warm temperatures forecast for this week mean that we will be picking up 20 GDD base 50 for much of the week and timings for more conventional materials will come quickly.

Pear bloom is over. Fruit are 14 mm in diameter.  Frost ring are apparent on many fruit pear psylla are out at all different stages.

Small fruit

Blueberry bloom is winding down. Most varieties and sites are in petal fall. Cherry fruitworm and Cranberry fruitworm adults are being caught. Egg hatch has not begun so insecticide sprays can wait until after bloom. Remove beehives before applying insecticides in blueberries. Tussock moth larvae are being reported in fields where they are a problem. Fungicide applications should be focused on mummyberry and anthracnose control.

In Grapes, Concord and Niagara flower clusters are separating.  Grape berry moth adults are being trapped, but egg laying has not begun, so insecticide sprays are not needed now. Thursday’s rain was a black rot infection. Phomopsis and downy mildew were found late last week. Growers should be protecting the shoots and flower clusters from phomopsis and other diseases before the forecast rain this weekend.

Strawberry bloom continues many fruits are thimble sized.

Early Summer Raspberries, such as Prelude are blooming.

Cranberry shoots are elongating and flower buds are visible. Cranberry beds are greening up. Pre bloom sprays to reduce fruit rots should be applied before the flowers open.