Saturday, October 10, 2015

Dooley and Hirschi crops destroyed by scab

    Thirty years ago, the Dooley pecan cultivar was the nut prized for home consumption by all the workers at the Pecan Experiment Field. Although not a large nut, Dooley shells out in halves producing a beautiful light colored kernel with outstanding flavor. However, over the years this cultivar has become increasingly susceptible to pecan scab. In 2015, our Dooley trees received the same three applications of fungicide that we sprayed on all of our pecan cultivars. Somehow, Dooley nuts still became covered with black scab lesions (photo at right).  This year, the Dooley crop will be 100% stick-tights and we'll suffer a total crop loss on this cultivar.

  Hirschi was another cultivar that suffered from extreme scab infection in 2015.When I inspected the crop on our Hirschi trees, I found that some shucks had split in spite of a 100% scab infection. The photo at right gives you a good idea of how scab effects nut production. The Hirschi nut cluster on the left side of the photo was photographed in Illinois and was largely free of scab infection. The scab covered Hirschi cluster came from our trials in Kansas. Nut size is significantly smaller for the Kansas grown Hirschi pecans where shucks are covered in scab.
    The difficultly we've experienced controlling scab on Dooley and Hirschi in 2015 has also occurred in previous growing seasons. Our inability to control scab on these two cultivars means that I definitely won't be grafting any more Dooley and Hirschi in the future.