Friday, June 7, 2019

A bad case of pecan leaf phylloxera

    I have been scouting pecan trees for signs of pecan nut casebearer activity and have made a couple of important observations. I haven't seen any casebearer as of today, June 7th and every native pecan I've looked at is loaded with nuts. It looks like 2019 will be a year of over-cropping and it may beneficial to skip the casebearer spray and to allow casebearer to help thin the nut crop.

    During my rounds of looking at wild pecan trees for casebearer activity, I came across a tree with the worst case of pecan leaf phylloxera that I have seen in a very long time (photo at right). The pecan leaf phylloxera is an aphid-like insect that causes the tree to form galls around these plant sap-feeding insects. Note that the galls are confined to the leaf blades.
    Once the galls are formed, there are no control measures for this pest. Later this summer, all seriously gall infested leaves fill drop from the tree. 
    Insecticide treatments are effective for control of this pest but must be applied before galls form over the insect. For pecan leaf phylloxera, a single insecticide application made at leaf burst will control this pest. Mark infested trees this summer and plan on spraying those trees next spring.
    You can read more about the pecan leaf phylloxera in a previous post.