Submitted to: Journal of Sustainable Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2007
Publication Date: 3/1/2009
Citation: Mccutcheon, G.S., Simmons, A.M., Norsworthy, J.K. 2009. Effect of Wild Radish on Preimaginal Development of Diabrotica balteata and Agrotis ipsilon. Journal of Sustainable Agriculture. 33:119-127. Interpretive Summary: Wild radish is a weed that commonly grows in the southeastern United States. It produces some chemicals that may be harmful to pests of agricultural crops. A study was conducted to determine any effect of extracts of wild radish on the ability of selected insect pests to hatch and develop. The extracts were taken from roots, stems, and leaves of wild radish. Liquid solutions of the wild radish extract was exposed to immature banded cucumber beetles and black cutworms over different amount of time in laboratory tests. These are two economically important insect pests. Hatching of the beetles was delayed, and survival of the beetle larvae was decreased. There was not a consistent reduction in hatching of the cutworm eggs as compared with a treatment of only water. The highest concentration (100%) and longest exposure time (18 hours) resulted in the largest effect on the insects. This study demonstrates that extracts from wild radish can help suppress crop pests. More study is needed to determine the importance of wild radish in reducing insects in crops.
Technical Abstract: Aqueous extracts of wild radish (Rhaphanus raphanistrum L.) roots, stems, and leaves were examined for detrimental effects on hatching and larval development of the banded cucumber beetle, [Diabrotica balteata Le Conte (Coleoptera: Chrysomelidae)] and black cutworm [Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae)]. Hatching was delayed significantly in eggs of D. balteata exposed to the aqueous wild radish extract for 18 h. In some trials, the hatching percentage increased to levels similar to other treatments by the third and final day of hatching. In others, the percentage hatching remained significantly less in eggs exposed to aqueous wild radish extract for the duration of the study. The mortality rate of D. balteata larvae was increased significantly by exposure to the wild radish extract. Hatching of A. ipsilon eggs was delayed significantly after an 18 h exposure to the aqueous wild radish extract 4 d after treatment in only one of the six trials. In that trial, all treatment results were similar by day five. In other trials, hatching of A. ipsilon was decreased similarly in eggs exposed for 18 h in aqueous wild radish treatment as well as the water control. Although this study shows an effect of wild radish extract on two insect species, supplemental studies which utilize methods that do not rely upon an aqueous solution may better define the insect suppression activity of wild radish.