Tuesday, May 7, 2013

Slight freeze damage on young pecan leaves

     Last week, temperatures dropped to near freezing and we had a record breaking snow in May. Since that time,  spring temperatures have returned and pecan trees have resumed growing new leaves and shoots. Once the new growth expanded a little bit, I noticed a touch of frost bite along the margins of some leaves (photo of Gardner terminal at right).  Not every leaflet is affected and the terminals of new shoots look fine.
    This marginal leaf burn reminds me of potato leaf hopper damage. However, if you inspect the leaves carefully you won't find the feeding scars on main leaflet veins that are the tell-tale sign of leaf hopper damage. This cold weather leaf burn appears more random, with the severity and location of damage related to the leaf growth stage during the cold snap more than anything else.
    So far, I've found some freeze injury on all  pecan cultivars  and native pecan trees I've inspected. However, some trees have only a few minor spots of cold injury (like  USDA 75-8-9 pictured at left).

    Since new shoot terminals were not damaged on any pecan tree I've looked over, pistillate flower production should not be effected by last weekend's cold and snow.