Wednesday, February 4, 2015
Pecan scab on dormant twigs
During the winter months, you can check your trees for scab lesions on the one-year-old twigs. The amount of scab seen on the twig pictured at right is a good indication that Hirschi is very susceptible to the disease. All of those black lesions will be releasing spores next spring that will start new infections on leaves, nuts, and new shoots.
In 2009, the USDA released Mandan and promoted this new cultivar as being scab resistant. If you look at the twigs pictured at right, you will note that both Pawnee and Mandan have scab lesions. This tells me that Mandan is not scab resistant as promoted. However, we have yet to produce enough nuts on our young Mandan trees to determine how susceptible this cultivar is to nut scab.