It is not fun to write about a problem that has not been a problem! This picture was taken by David Schwegman in his orchard north of Georgetown. He showed me pictures of scale on some limbs he took earlier in the year when I spoke at the San Saba Pecan Field Day. Since then, he has more pictures and according to his email he is now seeing the immature “crawlers” as the young scale insects hatch and begin moving to a new location on the limb. I thought this was obscure scale, but others think it may be lecanium scale.
This might not be such a worry except that David is finding it more and more. Also, I am getting reports from other orchard owners finding scale on pecan limbs in their orchards. So, is this becoming a problem for pecan growers? Maybe, or maybe this is just one of those isolated issues that we occasionally see. Either way it is important to be scouting, especially when trees are bare (winter), and the scale is easy to see.
Organic treatments are dormant oils in winter, when there are no leaves, or now with Certis Biologicals Des-X or Sil-Matrix, Marrone Bio’s Venerate or Grandevo, and/or possibly some of the botanical organic oils (cinnamon, garlic, thyme, etc.). Be sure to spray a limb or two in the afternoon heat first before treating the whole orchard with anything that has an oil or soap base. Shouldn’t take more than 30 minutes to see if it affects the green leaves in the heat!