Biology and Feeding Preferences of Spodoptera Frugiperda (Lepidoptera: Noctuidae) On Maize And Selected Vegetable Crops

Abstract

Purpose : Fall Armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera, Noctuidae) was recently reported for the first time in Sri Lanka in Oct 2018 as a new invasive pest of maize. Therefore, the objectives of present study were to study biology and to evaluate feeding preferences of S. frugiperda on maize and selected vegetable crops. Research Method : During the experiment, newly hatched larvae were fed with maize, cabbage, okra, beans, radish and brinjal leaves under laboratory conditions. Maize was used as the positive control. Duration of development from larva to adult, pupal weight, pupal length, sex ratio, survival percentage, and oviposition (Choice and No-Choice test) on different vegetable crops were evaluated. Findings : Results of the feeding preference test envisaged that there was no host dependent variability among neonate larvae for maize, cabbage, raddish and brinjal. The highest damage (50-75%) was reported in larvae fed on okra, and (25-50%) damage was showed in beans after 24 hours of inoculation. The highest survival percentage of larvae (80%) and shortest larval development period (23.8±0.3days) were reported in larvae fed with maize where as it was the longest in brinjal. The highest oviposition (4.1±1.2 in Choice test and 3.6±0.7 in No-choice test) was observed in maize compared to other crops. With the absence of the most preferred host (maize) for oviposition, other hosts were used by the pest. During the off season Fall armyworm could survive in alternate crops. Research Limitations : Field observations were not carried out to confirm (validate) the laboratory observations with the time limitation. Originality/ Value : The research provides interest and idea about the survival mechanism of S. frugiperda during off season of maize and potential alternative host plants of the pest. It identifies the possibility of moving of S. frugiperda into five vegetable crops and thereby make awareness of the farmers about the pest to follow the suitable management practice of the S. frugiperda.