SW Michigan Fruit Update

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June 27, 2006

Mark Longstroth

Weather

Temperatures last week were in the 70s and 80s with lows in the 50s and 60s.  Scattered rain fell Thursday and Sunday with rainfall totals less than a tenth of an inch.  Topsoils are very dry and growers are irrigating.  Soil temps are in the 70s.  This week’s forecast is for cooler weather with highs in the 70s and chance of thunderstorms.  The GDD below are from the Enviroweather site. We picked up 200 GDD base 42, 170 base 45 and 130 base 50.

Southwest Michigan Growing Degree Day Totals March 1 through June 25, 2006				Grapes, from April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
Scottdale:	1551	1303	942	912
SWMREC:	1512	1255	886	854
Bainbridge:	1585	1324	949	915
Hartford:	1409	1165	819	792
Lawton	1605	1348	974	949
South Haven (April 1)	1239	1032	729	729
Grand Junction:	1583	1327	962	925
Fennville:	1398	1151	804	776

 

General Insect Activity

Leafhoppers are abundant.  Japanese beetles are out but not in great numbers.  Expect more beetles to emerge after a good rain.  Picture wing fruit flies such as cherry fruit fly, apple maggot and blueberry maggot will also emerge now after 0.25 inches of rain.  Red-banded and Oblique banded leafrollers are out.  Tarnished plant bug activity is declining.  Rose Chafers are declining.  Plum curculio activity is light.  You can use the Enviroweather site monitor the GDD model for some pests if you know its emergence or Biofix at your site.

Tree fruit

Apricot fruit are coloring; harvest is about two weeks away. 

Peach fruit are 1.75 inches in diameter and some growers are still hand thinning.  The second generation of oriental fruit moth is emerging.  Biofix in Southern Berrien County was about April 18 at 180 GDD base 45.  Egg hatch of the second generation of OFM should begin this week about 11500 GDD past Biofix.  Thrips are showing up.  The dry weather is helping this pest.  Peach fruit show tarnished plant bug damage and rusty spot (powdery mildew).  Bacterial spot is generally minor. 

Sweet cherry harvest is underway.  Birds are a problem.  Brown rot has been reported in fruit clusters so fungicides to control brown rot should be applied.  Cherry fruit fly traps should be out, especially where sweet and tart cherry varieties are grown together. 

Tart cherry harvest should begin this weekend.  Growers need to protect against brown rot and cherry leaf spot.  Cherry fruit flies have not been caught.

Plumsare variable.  Shoot growth is stopping so black knot is no longer a problem. Brown rot was also reported in plums.  White apple leafhoppers are causing stippling of the leaves. 

Apple fruit are about 1.5 inches in diameter.  Growers are still hand thinning.  Oriental fruit moth trap catches are up signaling the beginning of the second generation.  Codling moths were still flying and egg hatch continues. We set Biofix for CM on May 25 with 328 GDD at SWMREC.  We expect egg hatch to continue for another 1000 GDD past Biofix about 1325 GDD base 50.  Obliquebanded leafroller egg hatch is beginning. OBLR Biofix on Monday June 12 at 1150 GDD base 42 and egg hatch should begin 400 to 450 GDD after Biofix.  European red mites and predator mites are being found.  Five mites per leaf is the treatment threshold for European red mite from mid-June to mid-July.  Apple maggot has been trapped in Southern Berrien County.  Fungicides to reduce sooty blotch and flyspeck should be included in cover sprays.  Leaf drop due to scab in common in unsprayed orchards.  Growers need to maintain scab protection if they have leaf lesions in their orchards.  Fire blight shoot strike symptoms are appearing.  Shoot strike is when the bacteria are carried from infected shoots to healthy shoots by leafhoppers.  The infection occurs on new shoots but does not appear to be associated with any adjacent infections.  Trauma blight could be a problem if we get severe weather in these orchards with oozing shoots. 

Pear fruit are about an inch in diameter. Pear fruit are some time attacked by codling moth at the end of the first generation flight

Small fruit

Blueberry harvest has begun in early varieties.  Anthracnose fruit rot is the main disease concern now.  Alternaria fruit rot is more a disease of over ripe fruit.  Cane collapse due to phomopsis is common.  Powdery mildew is showing up.  Cherry fruitworm and cranberry fruitworm are still being caught in pheromone traps, this means egg laying is continuing. Blueberry Maggot flies are out and growers and scouts should have traps out.  Growers should be scouting for Japanese beetle, leaf rollers and tussock moth larvae.  Blueberry tip borer damage can be found in new unsprayed plantings.

In Grapes, primary and secondary fruit clusters are past bloom and into the small fruit stage.  Grape berry moth larvae are feeding in the clusters.  Post bloom sprays are due.  Grape leafhoppers are becoming easier to find.  Rose Chafers are scarce.  Phomopsis leaf lesions are common in most plantings. 

Strawberry harvest is over on most farms.  Sap beetles were common in many Upick fields. Some growers have begun renovation.  Potato leafhopper burn is common in many fields.

Raspberry harvest is about a week away.  Growers should be scouting for Japanese beetles. Pre harvest fungicide and insecticide sprays should go on soon. 

Cranberry bloom continues.

Miscellaneous

There will be no Monday Fruit IPM update on July3. The next and last Monday Fruit Update meeting will be Monday July 11, at the Fruit Acres Farm in Berrien County, at 5 PM.  Grape IPM meetings will be held in Berrien and Van Buren Counties on Thursday, July 13.  The morning meeting will be from 10 AM to noon at the Cronenwett Farm Shop at 70123 28th Street east of Lawton. The afternoon meeting will be at the Southwest Michigan Research & Extension Center from 2 to 4 PM.  There will also be a twilight grape IPM scouting IPM meeting July 20 at Bob Dongvillo's farm, south of Benton Harbor.