Laboratory evaluation of host plant resistance on Sri Lankan Maize Landraces to fall Armyworm (Spodoptera frugiperda Smith) (Lepidoptera: Noctuidae)

Abstract

Recently invaded fall armyworm in Sri Lanka has been regarded as a major maize pest and became a crucial pest with substantial yield losses. Management of the pest via sustainable environmentally friendly measures is essential and encourages rather than the usage of synthetic chemicals. The latent resistivity of traditional maize landraces, which are favoured by the Sri Lankan farmers has not yet been investigated. Thus, a laboratory experiment was designed to investigate the leaf-feeding and oviposition resistance of FAW in Sri Lankan maize landraces. Eight local (OP) maize landraces (SEU02, SEU06, SEU09, SEU14, SEU15, SEU16, and SEU17) with comercial varieties (Bhadra and GT722) were used. The feeding and oviposition preference assays were conducted and revealed that none of the accession showed complete resistance to FAW feeding, but detected differences in acceptance and preference with varying degrees. Nevertheless, a significant difference was observed in morphological traits viz. leaf trichomes density and leaf thickness. The Oviposition preference bioassay found that Bhadra (χ2=5.4, df =1, p=0.02,12/3) reported highly preferred by females as oviposition with the high mean number of eggs (638.40 ± 4.20), while SEU02, SUE06, SEU09, SEU10 and SEU17 (χ2=5.4, df=1, p=0.02, 3/12) reported with low preference. Our study provides insight into the density of trichomes on leaves does not seem to be linked to larvae feeding preferences at later stages of the larval phase.