Wednesday, October 5, 2016

Hurricane Matthew Preparation for Caneberries

The latest forecasts have Hurricane Matthew just skidding the southeastern coast of NC. Caneberry Growers in Eastern NC (and the rest of the southeastern US) should be preparing their fields now and be prepared after the rains leave.

Here are some things that can be done before the storm:

IF YOU ARE IN AN AREA WITH HIGH PREDICTED WINDS: You should consult with your tunnel manufacturer to determine how much wind your tunnels can withstand. Removing or skinning the plastic off the tunnels  is a whole lot less costly than having the entire tunnel mangled.

IF YOU HAVE A SHIFT OR ROTATING ARM TRELLIS: Lay the trellis in the horizontal or down position and make sure it can stay in that position. Some trellises do not have the capability to lock in the horizontal position. If that is the case, it may be better in the upright position.

POTENTIAL FOR ELEVATED DISEASES: Canes if properly trellised should not lodge as a result of the wind and rain. However, there may be some physical damage to canes. Make sure you walk your fields before and after the storm. There may be a need to do some extra pruning and use of a fungicide if you can get out into the field after the storm. Phil Brannen, UGA plant pathologist recommends a spray for Cane blight, before the storm. See the SRSFC for recommended chemicals.

After the hurricane passes there may be some soils that have flooded. Here is some information from a previous post from Cornell University. Since most of the berry crops have already been harvested, we are primarily concerned with flooded fields effects on roots.

This is an excerpt form an article is provided courtesy of Cornell University. It was written for flooding situations in the northeast in the late summer. However,  a flooded field poses similar problems for plant survival and is still an issue in the fall, as plants are not yet dormant. 

Steve Reiners and Marvin Pritts
Dept. of Horticulture
Cornell University


How long a crop can live once it is flooded and what may be the effect on yield? Berry crops can tolerate a great deal of flooding when they are dormant, but when actively growing in summer, flooding for any length of time can be detrimental. This time of year is particularly bad because plants are preparing to make flower buds for next year, and stress can compromise this process. If plant roots were under water for more than 48 hours, expect next year’s crop to be compromised as well.

Plants previously flooded may develop an off-green or yellowish color.  These plants are suffering from a complex of nutrient deficiencies, nitrogen, phosphorus, potassium and perhaps others, even though the soil contains adequate amounts. But the main deficient element is oxygen. Plant roots need oxygen to take up nutrients and water to utilize the photosynthate from the tops and to grow. With the heavy rains we have had, soils are saturated; that is, nearly all of the pore space is filled with water, leaving little room for air. Ideally, for good root growth 50 percent of the pore space should be filled with air. As soils drain, air is drawn into the soil, but when it rains, the water forces the air out of the pores. As is obvious to all, what is needed now is several rain-free days so the soils can drain and draw in air to stimulate root growth and help disperse toxic compounds that accumulate when plants lack oxygen.  Once the plant roots get adequate oxygen they will begin to grow and take up the nutrients present in the soil. Anything that can be done to remove surface water will be helpful.

Many plant diseases will be much worse following flooding rains (e.g. Phytophthora and Botrytis), so closely monitor crops and manage these diseases. Phytophthora spores are spread under flooded conditions, so chemical treatment may be warranted in susceptible crops (red raspberries and blackberries).

(Thanks to Steve Rieners and Marvin Pritts at Cornell University for sharing this with us.) 

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