Thursday, July 28, 2011

Symptoms of drought

   We haven't had a summer this hot and this dry in SE Kansas since 1980. Talk to some old-timers and they still recall the droughts of the mid-1950's. Before that, it was the dirty '30s and the droughts that created the depression era dust bowls.   
    Pecan trees tolerate heat and dry weather better than many tree species but we are now seeing signs of drought stress especially on young trees. In the photo at left, you will note several dry, brown leaves among healthy, green leaves. This is not the result of some foliar disease but is a perfect example of how pecan trees deal with drought. When the supply of water becomes very limited, pecan trees will conserve water by shedding leaves to reduce the amount of water lost to transpiration. The oldest leaves (at the base of this years new growth) are the first to be shed.
    Watering trees at this point will not "cure" the leaves that have already turned brown but will help trees retain all the green leaves still on the tree.