Identification of structural and chemical traits in Juglans regia associated with host plant preference of Batocera horsfieldi

Abstract

AbstractCommon walnut Juglans regia L. suffered devastating damage from the white‐striped longhorn beetle Batocera horsfieldi (Hope) in southwest China, which resulted in a dramatic decrease of local walnut production. However, the control of this wood‐boring pest with traditional methods is difficult as a result of its cryptic feeding habit. We proposed that developing host‐plant resistance is a more effective way of controlling this insect with long‐term benefits. One way of improving host‐plant resistance is to identify plant traits related to host‐plant preference of targeted insects. In the present study, we investigated the differences in feeding and oviposition preferences of B. horsfieldi on four J. regia cultivars in the field and tested whether such preferences are associated with structural and chemical traits in plant branches. The results obtained showed that the host‐plant resistance of J. regia cultivars to B. horsfieldi was related to increased wood density, higher amounts of cellulose and lignin, and higher contents of tannins, total flavonoids and total phenolics, whereas the susceptible cultivars were characterized by thicker bark, higher contents of water, sugar and soluble protein. The identified traits involved in host‐plant preference can subsequently contribute to the selection and breeding of resistant J. regia cultivars to B. horsfieldi.