Effect of narrow-leaved plantain cultivar on development of two geometrid pests, Scopula rubraria and Epyaxa rosearia.

The increased use of narrow-leaved plantain Plantago lanceolata as forage in New Zealand has led to the emergence of two native moths, Scopula rubraria and Epyaxa rosearia, as significant pests. Plantain is known to contain defensive compounds against insects and a laboratory study was undertaken to compare the growth and development of both moth species on four plantain cultivars and one breeding line. Larval feeding and development was found to vary with plant line and leaf age, with Ceres Tonic and especially SF Boston the most favourable plantain lines for both pests. No E. rosearia completed larval development on mature foliage from Luisetti Tuatara or the breeding line JC Upright. While the differences between plant lines appeared to be related to foliar digestibility and metabolisable energy indices, rather than glycoside levels, the results indicate that narrow-leaved plantain has attributes that could be exploited to achieve better resistance against these pests. [ABSTRACT FROM AUTHOR]