SW Michigan Freeze May 3, 2004
Van Buren MSUE Home
Fruit Pages
For more information on recognizing frost injury in tree fruits see my Freezing Injury Page.
Weather
A frost occurred across Western Michigan on May 3, 2004. Temperatures ranged from 28 to 26 in most of the fruit sites. Lows of 25, 24 and even 22 were also reported. These freezing temperatures are in the middle of the damage range for fruit at and after bloom. Damage varies widely from site to site depending on elevation, air drainage and crop development. Southern Berrien suffered more damage. Losses across all fruit crops are consistent with 28-26 degree temps and a relatively high temperature inversion.
Tree fruit
Peach fruit were in the shuck. It is hard to assess frost damage now. The heavy bloom means that we probably did not suffer yield losses in peaches. Large fruited fruits need less flowers to become fruit for a full crop of 3" peaches. Our bloom was so heavy that we could have lost 90% of the flowers and still had a good marketable crop.
Sweet
cherry fruit were at shuck split and suffered heavily from the frost with cherries in
the higher sites suffering less damage. The sweet cherry fruit to the right were frozen
and have a "watersoaked" appearance after they have thawed out.
Tart cherries bloom
was ending. Tart cherries suffered lighter damage than sweet cherries and it is hard to
assess damage now. It appears that we suffered about 25% losses in the bottoms of the
trees and I feel that we suffered little loss in the upper portions of the trees. We will
know more when the fruit emerge from the shuck. The flower cluster to the left shows
little damage to the pistils inside the shuck. In some cases the style was burned by
frost but this will not hurt if the ovule ,which becomes the seed) has been fertilized.
Plums: European plum fruit are in the shuck. Japanese plum buds are at shuck split and suffered heavy damage. Growers should be applying black knot sprays. Protection needs to be maintained until the end of shoot growth.
Apples are at full bloom. Late varieties are at
king bloom. While the frost caused browning of the petals especially in Golden Delicious,
a lot of the pistils are undamaged. The picture above shows damaged petals and some of the
styles in the middle of the flower are black indicting that the flower was killed. We have
lost some of the king bloom but the heavy bloom this year means that harvest yields should
still be good. The picture to the right shows a dead king bloom and live side bloom. The
picture below shows live king bloom. The king bloom has the potential to be the
largest apple fruit in the cluster. Apple growers would prefer to set the king bloom and
thin off the side bloom. But having some live side blooms is better than losing your crop
to Frost
Pollination conditions over the bloom period have alternated between hot
and windy or 
cold and windy so pollination may be
more important than this frost in determining apple yield.
Pear bloom was ending. At this time pears do not appear to be much damaged.
Small fruit
Blueberries are at late pink bud and early bloom.
In general blueberries were not damaged. During bloom, sprinkler irrigation for frost
control is effective; see my articles protecting blueberries from freezing damage. Frost
damage was most severe in the southern areas where development was most advanced with
early varieties at full bloom. Leaves have unfolded.
Grape shoots had several leaves out and losses to
frost were about 10 to 20% of the shoots killed. Some
vineyards in low areas and in Southern Berrien County suffered more damage. The true
extent of the injury will not be known until the secondary buds came out. See the article
on the 2002 April 23 freeze. The photo at the right shows
the pattern of the loss. grape shoots were either killed or not killed and live shoots
were located on the same cane as ones that died.
Less advanced vineyards suffered less damage. Growers should maintain protective fungicide
sprays against powdery mildew, black rot and phomopsis. Early fungicide applications as
the flower cluster emerge will prevent infection of the cluster rachis during spring
rains.
This is a veiw of a frost pocket in a
grape vineyard where all the shoots were killed by the May 3 freeze in a low area where
the 
cold air settled. Areas that are green still have lots of green shoots
while dark areas have few green shoots. After the secondary buds begin growth, the frost
affected areas will green up and then we can assess the crop potential of frost damaged
vines.
Strawberry bloom has begun. There was light damage to the bloom where growers did not frost protect Monday morning.
Raspberries have leafed out and seemed to suffer little from the frost. Fall raspberries shoots were emerging from the ground and about 6 inches tall. It is likely that frost damage to the base of the shoots will stunt future growth and this year's primocanes will be short.
Cranberries were beginning to green up and not damaged by the frost.
