Spraying pecans to prevent diseases

   I've been scouting pecans for pecan nut casebearer every-other-day but as of June 11, I haven't seen anything. What I have seen, is lots of pecans. Every native pecan tree in our area seems to have a nut cluster on every terminal. In addition, my improved cultivars have a great crop. So this year I've decided to change my pest control priorities and concentrate on preventing pecan diseases.

    The photo at right shows a typical cluster of Gardner pecans. Gardner is a scab susceptible pecan cultivar that produced high quality large pecans. Right now every nut in the cluster is clean; no casebearer and no scab. If all the nuts currently set on this Gardner tree stay perfect until August, I'll need to shake about half the crop off the tree to insure good kernel fill and a decent return bloom.
   A light infestation of casebearer would actually be beneficial in helping thin down the crop. In sharp contrast, there is no way I want to allow scab to get established on this year's nut crop.
   Looking at the weather predictions for the coming week it looks like we can expect several rainy days. With the rain comes high humidity and perfect conditions for scab to spread. So today, I sprayed my trees with a systemic fungicide that will work to prevent scab infection for the next 10 to 14 days.
   I sprayed the fungicide even on scab resistance cultivars such as Kanza, Hark, and Lakota because these cultivars are not resistant to all pecan diseases.  I've found that early season fungicide applications can help prevent pecan anthracnose and downy spot from creating serious late season problems during wet summers.
  I plan on making additional fungicide applications as the season progresses depending on rainfall patterns.