Isolation and identification of trans-aconitic acid as the antifeedant in barnyard grass against the brown planthopper, Nilaparvata lugens (Stal) (Homoptera: Delphacidae).
Echinochloa crus-galli var. oryzicola growing in rice fields in Japan has been observed to remain free from damage by Nilaparvata lugens (Stal) even during heavy infestations. The antifeedant in this grass was isolated in the laboratory and identified as trans-aconitic acid [trans-1-propene-1,2,3-tricarboxylic acid], which is not present in rice plants. The acid, neutralised with calcium hydroxide to a pH of 7, showed a strong inhibitory action on the feeding of N. lugens at 0.25 and 0.5%, but the cis-isomer showed much less inhibitory activity.