Problems with Pecan Tree Roots

Root Suffocation

• Suffocation of tree roots is a common problem with pecan trees growing in poorly drained soils since the trees are highly sensitive to wet soil. Poorly drained ground tends to get increasingly saturated and deprives oxygen required for optimal tree growth. Root suffocation in pecan trees is characterized by declining tree health, dying top branches and the soil turning black with a putrid odor. Root suffocation in pecan trees is also common in orchards with accumulated layers of silt around trees due to flooding or application of additional soil around trees. Management includes correcting drainage and pruning the dying and weak limbs.

Phymatotrichum Root Rot

• Phymatotrichum root rot of pecan trees is a fungal root disease of pecans also referred to as cotton root rot and Texas root rot. The fungus causing the disease thrives mostly in poorly fertile, warm soil with high levels of calcium and leads to the rotting of tree roots. Closer examination reveals thread like fungus strands wrapped around sick roots. Early symptoms of the disease include yellowing foliage followed by sudden wilting and death. Start treatment with first evident signs of fungus on the tree. Prune the top half or more of tree growth and remove all foliage to reduce rate of transpiration. Do not use nitrate fertilizers in grounds where phymatotrichum root rot is a known problem.

Nematodes

• Nematodes are very small, microscopic worms that infest the roots of many plants. Pecan tree roots are susceptible to infestation from the ring, root knot, lesion and dagger nematodes such as Helicotylenchus, Mesocriconema, Pratylenchus and Trichodorus. Infestation of root nematodes are classified as a secondary root disease in pecan trees. To manage the disease, apply aldicarb to the soil or the use pre-planting fumigation in the ground prior to planting. There are no post-planting nematicides recommended for use in pecan tree roots.