Every year I seem to spot just a few leaves distorted by the pecan leaf roll mite (
Aceria caryae). Generally, the amount of damage is minor and we can simply ignore this pest. However, this year I have noted several trees in my orchard that are heavily infested with leaf roll mites (photo at right). In the photo, you'll note that the older leaves have thin leaflets but the newest leaves on the end of the shoot appear normal.
Looking closer at the mite-damaged leaves you will note that the edges of each leaflet are curled upwards and a roll of gall tissue has formed along the outside edge (photo at left). Leaf roll mites are in the eriophyid mite family: a family known for causing galls on plants.
I can not find any information on the life cycle of this pest but I don't expect the problem to become more prevalent in my orchard next year. Currently, there are no chemical control measures recommended for this pest but I may try applying a dormant oil spray on infested trees before bud break next spring. For the most part naturally occurring predatory mites keep the population of the leaf roll mites in check. Hopefully, nature's balance of predators and prey will be restored in the Spring of 2020.
