Sunday, April 15, 2012
Twig girdler damage on pecan
After laying eggs, the female cuts a grove in the stem. The girdling of the stem causes all the carbohydrates manufactured by the leaves above the girdle to become concentrated in the stem rather that being set down to the roots. The eggs she lays in late summer don't hatch until the following spring. But when they do hatch, the larvae feast on the carbohydrate enriched twig.
Twig girdlers are most often a problem in non-bearing pecan groves. Once pecan trees start to bear, insecticides applied in August and September to control pecan weevil also control twig girdler. In young orchards, picking up girdled branches every spring and burning them will help reduce the population of twig girdlers in the future.