Friday, July 27, 2018

Low pecan scab pressure this summer

Scab lesions on Peruque, 2018
    Many northern pecan growers have experienced a drier and hotter summer than normal in 2018. The downside of this weather pattern is that I find it hard to work outside in the heat of the afternoon, that is, unless I'm sitting in an air-conditioned tractor cab. The plus side is that we have seen a lot less pecan scab this summer. The other day, I searched my farm for signs of scab and found none. Although you should remember that I applied two fungicide cover sprays to my pecan trees back in June.
     So, I drove down to the old Pecan Experiment Field to see if I could find any scab. I started my search with two of the most scab-susceptible cultivars in our area--Peruque and Hirschi.  The Pecan Field was sprayed only once this year (shortly before I retired) so my chances for finding scab were much better.

Scab lesion on Hirschi, 2018
     I found scab lesions on both Peruque (photo above) and Hirschi (photo at left). Over the past three to four years, I was finding it almost impossible to produce these two cultivars without crop loss from scab. With just the few scab lesions present on these nuts this summer, Peruque and Hirschi should develop full-sized pecans and split their shucks normally. The hot, dry weather (especially in June) has sure helped slow the spread of scab this summer.

Scab on Peruque, 2015
    To remind you how bad scab can get on Peruque, I've reprinted a photo I took in 2015 (photo above). This scab infested nut was smaller than normal and produced far less kernel.