Tuesday, June 21, 2011

Pecan scab development 2011

   Over the past several years, pecan scab has developed into a massive problem for northern pecan growers. This year in SE Kansas weather conditions in May were perfect for scab infection of new leaves (photo at left) and new stem growth (photo below).
    I hope I convinced all growers to apply a fungicide with their casebearer spray (insecticide) to stop the spread of the scab fungus onto the nuts of scab susceptible cultivars. Today, I went out to scout the grove for scab infections on nuts and found that the combination of a fungicide application in early June and hot dry weather has prevented new infections on the developing nut crop.(Photo below)
    The question becomes--will additional fungicide applications be necessary?  The answers depends on you location. It seems that rain has been falling everywhere except extreme SE Kansas. We are dry and will probably skip additional scab sprays this year. In other northern pecan areas, rainfall has been abundant. This means a second fungicide spray should be applied 2 weeks after the 1st spray was made. Keeping scab off of expanding nuts is critical for achieving full nut size and kernel quality.