SW Michigan Fruit Update

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Southwest Michigan Freeze, April 30, 2008

Weather

A radiation freeze stuck Southwest Michigan on Wednesday April 30, with lows in the 20 to 29 F range. Freeze injury was wide spread but the severity of damage varied a great deal depending on the crop’s stage of development, the duration of cold temperatures and especially how good was the fruit site. Flatter sites with poor air drainage suffered the most. This freeze was very similar to freezes in 2002, 2004 and 2006.

Overnight Temperatures Report: Hourly average temperatures (Report issued 4/30/2008 8:51)
	4/29/2008					4/30/2008
Station	10-11 PM	11-12 PM	12 - 1 AM	1-2 AM	2-3 AM	3-4 AM	4-5 AM	5-6 AM	6-7 AM	7-8 AM
Bainbridge	29	26.8	25.6	25.1	24.4	24.7	24.2	23.3	22.2	26.1
Benton Harbor (SWMREC)	33.2	31.2	28.9	27.8	27.5	27	27	26.8	26.6	28.8
Berrien Springs	31.5	30.9	29.4	28.6	27.9	27.2	26.8	27.8	28	31.4
Fennville	33	32.5	31.6	27.8	27	25.9	25.1	24.8	24.3	27.5
Grand Junction	30.8	28.7	27.8	26.6	25.9	25.1	24.2	24.2	23	25.9
Hartford	29.2	27.7	27	25.9	25.3	24.6	24.1	23.5	23	26.6
Keeler	33.8	33.6	33.8	31.6	30.5	30.5	30.7	30.6	29.6	31.9
Lawton	32.7	31.5	30.7	28.5	27.1	25.8	26.3	27.5	26.3	29.2
Scottdale	32.4	31.1	30.1	29.7	28.8	28.4	28	27.6	27.5	29.7
South Haven	28.7	27.6	27.3	27.2	26.4	26.2	25.3	25.4	25.1	26.5

Tree fruit

Temperatures below 28F will damage the flowers on blooming fruit trees. While the recorded lows could have caused severe damage our examination shows that damage in stone fruit does not seem to be as bad as the critical temperature table would indicate. Damage in some apple varieties was worse than I would have expected from the table. We did have cold temperatures for a relatively long time. Longer than the 30 minutes uses for determining the critical temperature.

Apricots were in the shuck. Damage was very site specific. Poor sites suffered greatly, but good sites still have good crop.

Peaches were blooming. Damage is generally light at good sites in the major production area of Berrien County. Early non-showy types were hit hardest. Many unopened flowers were not damaged. A good crop remains for most varieties but some varieties suffered and there might be times when flow to the market is light during peach season.

Sweet Cherries had bloomed and the leaves were emerging. Damage seems to be variety specific, varies from heavy to light. Better sites and later varieties suffered less damage.

Tart Cherries were blooming. Damage seems to be site specific, but generally light.

In Plums, Japanese plums bloomed and were at petal fall. European plums were blooming. Stanley plums were just beginning to bloom. Damage in plums varied widely with early blooming varieties fairly hard hit. Good sites still have a crop.

Apples were at pink. King bloom of early varieties such as Idared and Zestar were open and killed. Damage varies by variety, often the king bloom was killed. Some growers report very heavy damge. There are big differences within the orchard and less in good sites. There were big differences between varieties and they were not always based on bloom timing or development. Late varieties in tight cluster were also hurt.

Pears were at first bloom. Pear damage varied by site, close to the lake there was little damage.

Small fruit

Blueberry fruit buds were at pink bud and suffered little damage. Early varieties were nearing bloom and the petals were damaged and may not open. Few growers used sprinklers.

In Grapes, I have learned that you cannot estimate injury soon after a freeze but need to wait about a month to see which buds survived and the number and fruitfulness of secondary shoots. Juice grapes were at bud burst stages. Damage in the Paw Paw area to juice grapes was severe. In Berrien County damage varied. It was not unusual to see the buds at the tip, which had burst killed by the freeze and buds at the base of the shoot, at bud swell undamaged. In wine grapes, damage varied greatly by variety. Some French Hybrids were advance enough to be hurt, but other varieties were not damaged. Vinifera grapes were at swollen bud and suffered little damage. Southern Berrien County suffered much less damage.

Strawberry flower trusses were emerging from the ground. Many strawberry growers protected with sprinklers and little damage was reported.

Raspberry and Blackberry leaves were unfolding and some show frost/freeze puckering but few new primocanes were damaged

Cranberry beds are greening up and tip buds are swelling and beginning to burst. Some growers protected with sprinklers. There seems to be little damage.