SW Michigan Fruit Update

Check the Index for earlier postings

April 18, 2006

Mark Longstroth, Bill Shane, Al Gaus

Weather

Last week was warm and mild.  Temperatures were above 70 and above 50 at night.    Growing Degree Day accumulations are a little ahead of normal for this time of year.  We are caught up with last year and should fly by 2005 on April 22 (It snowed last year).  We are still behind 1998 and 2000 be a week or more.  This week’s forecast is for cooler weather, with highs above 60 and lows above 40. This should slow down fruit bud development. Currently, fruit bud development is similar to last year.  There is a chance of rain and thunderstorms late in the week.  These could be infection periods for early fruit diseases if the wetting periods last long enough.  Look at the new Weather for IPM decisions in Michigan site at http://www.enviroweather.msu.edu/home.asp.  The weather stations below are linked to the respective pages at this new site.

Southwest Michigan Growing Degree Day Totals March 1 through April 16, 2006				Grapes, from 4/1
Location	GDD 42	GDD 45	GDD 50	GDD 50
Scottdale:	234	178	107	77
SWMREC:	250	186	110	78
Bainbridge:	263	197	114	70
Hartford:	226	164	95	68
Lawton (est.)	265	200	119	84
Grand Junction:	251	189	112	75
Fennville:	208	152	88	60
Lawton site is estimated using Bainbridge data for March since this was the best match for temps in April when both stations were operating

Tree Fruit

Tree fruits are blooming.  Bee activity is heavy.

Apricot bloom is ending; most fruit are in the shuck.  Growers need to protect against brown rot.

Peaches are blooming. On some trees the fruit buds have fallen off but generally the bloom is very heavy.  Growers should watch the weather and be prepared to control brown rot. This disease likes warm wet weather like fire blight.  Temperatures from 70-77 F are ideal, and under humid wet conditions infections can take place in less than 6 hours. Infection takes 12 hours at 60F and 18 to 24 hours as the temperatures go below 50F.  Bloom is so heavy that some growers are considering blossom thinning.  We caught the first Oriental Fruit Moth over the weekend.  We will use April 16 with a GDD of 180 Base 45 at SWMREC for Biofix.  Egg hatch should begin about 150-170 GDD base 45 after Biofix and chemical controls are focused on egg hatch. Growers planning to use pheromone disruption should have their dispensers out now. 

Sweet cherry bloom has begun. Early varieties are in full bloom. Hedelfingen is at first bloom. Sweet cherries are very susceptible to brown rot.  The window for copper on sweet cherries is closed. 

Tart cherries: Montmorency cherries are at tight cluster and should be at white bud by the end of the week. Balaton cherries are more advanced open cluster.  Growers can still apply copper to reduce bacterial canker, but these warm dry weather conditions are not what that bacteria needs to infect. Canker prefers cold wet conditions and invades freeze-damaged tissues.  Cherry leaf spot is not a concern until the leaves begin to unfold after bloom.

In Plums, Oriental plums are in full bloom. European plums buds are at open cluster and will be at white bud soon.  Bloom is about a week to 10 days off.  Black knot control normally begins at bloom when shoot growth starts, but if you have black knots in the orchard apply you should apply controls as soon as growth begins. 

 

Apples are tight cluster and ‘Red Delicous’ is showing pink.  The window for applying oil to control European red mite and Rosy apple aphid with oil is closing rapidly.  Several wetting events were marginal infection periods for apple scab. You can check for scab and several other pests at the Weather for IPM decisions in Michigan site. Lawton was the only site to record an infection period but several others with scab forecasters also predicted scab. The symptoms should show up about April 23.  We are now trapping Redbanded Leafroller and Oriental Fruit Moth.  Leafroller should be feeding in shoot tips and flower clusters.  Scout now to determine if pink sprays are needed. Spotted Tentiform Leafminer should be flying.

Pears are at white bud. Growers need to worry about Pear Psylla and pear scab.

Small Fruit

The Blueberry and Grape links below lead to the MSU websites for these fruit developed from the pocket-scouting guides for these crops.  These sites are excellent resources for cultural and pest control information.

Blueberry fruit buds are opening and leaves from upper vegetative buds are half an inch long and will unfold soon.  Mummy berry shoot strike infection can still occur.  Lower leaf buds are at about 1/8 inch green tissue exposed.  Mushrooms were found at the SWMREC station so wet weather can lead to infections. 

Grape buds are swelling and pink is visible on the more advanced buds.  Some growers are applying dormant sulfur and copper sprays to reduce overwintering phomopsis.  This will be a topic addressed at the Grape IPM meetings Thursday in Berrien and Van Buren counties.  Flea beetle were found last week and yesterday.  Growers should also be scouting for cutworms.

Strawberry flower buds are emerging from the crown.  Growers are putting down straw mulch and setting up irrigation systems for frost control.

Raspberries leaves are emerging on blackberry and summer raspberry canes.  Fall raspberry shoots are 2 to 6 inches tall.

Cranberries are still dormant, but some areas of the beds are greening up.

Miscellaneous

Growers are finishing pruning, clearing brush and applying herbicides.

The current Fruit CAT Alert should be available at http://www.ipm.msu.edu/fruit-cat.htm the next issue will be April 24.

The next Monday Fruit Update meeting will be, Monday April 24, 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, April 20.