Fruit tree damage from the cold

With the frigid temperatures blanketing the state, damage to fruit crops is likely. We were fortunate in having good snow cover prior to cold temperatures to protect roots from damage. Trying to predict the amount of bud/tree/vine damage we might expect is a little complicated because damage is influenced by many factors including minimum temps, duration of cold temps, acclimation and previous season's crop load.

Apples and pears are very hardy but we're close to the temperatures where we could start to see some bud damage. It seems unlikely that bud damage will be severe enough to reduce crops.

Peaches and Nectarines -- The rule of thumb I learned from Dick Hayden is that you start to see some flower bud kill at --10 F and for every degree below --10 F you lose 10% of your flower buds. At --20F expect complete flower bud mortality. Given that the temperature here right now is --13 F (and assuming this is as bad as it gets), we expect to have some early thinning occurring but crop reduction shouldn't be too severe.

Sweet and tart cherries -- tart cherries are a little more hardy than sweets, but we could see a little bud damage to both sweets and tarts, but at current temps this is unlikely to limit 2014 crops.

Blueberries -- highbush blueberries are generally tolerant of temperatures down to --15, but the extended period of cold will likely lead to some flower bud kill.

Blackberries -- thorny and thornless blackberries are not hardy below --10 so we would expect to see considerable damage to vascular tissue in canes and potentially buds themselves. In severe cases we would expect all above ground growth to be killed. Blackberries commonly exhibit a delayed winter injury response where the buds may have survived the winter cold and begin to grow in the spring, but the damage to the vascular tissue in the canes results in collapse of the new growth a few days or weeks after the start of growth.

Raspberries -- red and black raspberries are fairly cold hardy and we would expect minimal damage to varieties that are adapted to the Midwest. Some red raspberry varieties from the Pacific Northwest are not very cold hardy and may have been damaged.

Grapes -- varieties will vary widely in amount of damage. Grapes have a compound bud, with primary, secondary and tertiary growing points. The primaries are usually the first to show cold damage. We would expect hardy hybrid and American varieties to have 0-25 percent primary bud damage at the temperatures we experienced. That is manageable, as we can adjust pruning severity to account for those losses. Less hardy hybrids may have 50 percent or more bud damage, which could lead to some yield reduction and potentially cane and cordon damage. Cold tender vinifera varieties likely have experienced considerable damage to buds, canes, and cordons and possible damage to trunks above the snow line.

The extended duration of cold temperatures expected may increase the amount of damage we see. We'll know more in a week or so. Right now there's nothing growers can do except stay inside, keep warm, and keep their fingers crossed. (written by Peter Hirst and Bruce Bordelon)

Winter damage of Shade Trees

The weather has been hard on shade trees too. The heavy wet snow then freezing temperatures have made these tree more susceptible to braking limbs and other damage. Please use caution when dealing with damaged trees. Safety should be the priority at all times. Use caution in and around trees during and after extreme weather as falling limbs and debris may pose a hazard long after the storm has passed.

Even after the snow is gone use caution when inspecting trees for storm damage, look for splits or cracks in the trunk and major limbs, as well as disturbed soil around the trunk. These are signs of a structural problem in the tree. Never climb a damaged tree to remove limbs or attempt any type of clean-up on a tree that is leaning or has a split trunk or branches. These tasks are best left to professionals. Never remove or trim branches that are interfering with power lines. Instead, contact your local power company, they have the proper equipment to deal with power line problems.

When removing fallen branches under the tree's canopy, watch for falling ice and limbs. Icicles can form high in the canopy and be hard to spot. Icicles can be very dangerous. Wait for the ice and snow to melt before pruning damaged branches that can be reached from the ground.

Always be wary of individuals who go door-to-door soliciting your business. Reputable tree-care companies are typically too busy to do this. Say "no thank you" to anyone who offers to top your tree. It is not too early to begin planning to replant trees destroyed by storms. It is said the best time to plant a tree is yesterday. Good luck and be safe.

For more information please call contact Ann Delchambre 765-653-8411 or email adelchambre@purdue.edu

Upcoming Events

January 13 - Area Indiana Beef Cattle Association meeting, Clay County Fairgrounds

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