Growth inhibition of Fall armyworm (Lepidoptera: Noctuidae) Larvae Reared on Leaf Diets of Non-Host Plants

Abstract

Chemists and natural plant product scientists have shown an interest in compounds from exotic plants that are considered non-hosts for the fall armyworm, Spodoptera frugiperda (J. E. Smith), but may serve as sources of materials that reduce feeding and growth of herbivorous insects. We report here results of laboratory bioassays with neonate and fifth instar fall armyworm fed on a standard diet alone and on an amended diet with celufil or leaves from dogwood, Cornus florida L., hydrangea, Hydrangea macrophylla (Thunb.) Seringe, black cherry, Prunus serotina Ehrh., or Bradford pear, Pyrus calleryna Decne. The neonates had reduced growth and frass production when fed diets containing leaves of dogwood, hydrangea, black cherry and Bradford pear while fifth-instars had reduced consumption and weight gain when fed the hydrangea leaf-diet. These results suggest a toxic component in the leaves of hydrangea that reduces the development of the fall armyworm neonates and fifth instars. The results also indicate that the leaves of dogwood, black cherry and Bradford pear have growth inhibitors present in their leaves that adversely affect growth of neonate fall armyworm. Because fifth instars performed similarly to controls when fed dogwood, cherry or pear leaf-diets, older larvae may be able to overcome the plants natural defenses better than neonates.