Identification and quantification of hydroxamic acids in maize seedling root tissue and impact on western corn rootworm (Coleoptera : Chrysomelidae) larval development

Hydroxamic acid content was analyzed in the root tissue of four maize, Zea mays L., lines using high-performance liquid chromatography (HPLC) and rela ted to western corn rootworm, Diabrotica virgifera virgifera LeConte, larva l development and survivorship. Maize lines evaluated included Mp710 (PI 59 6627), MpSWCB-4 (PI 550498), Sc213 (PI 548792), and Dk580 (DeKalb commercia l hybrid). Maize plants from each line were grown in test tubes containing a transparent agarose gel medium in a growth chamber. After 8 d of growth, root tissue of each line was harvested and hydroxamic acid content analyzed using HPLC. Three hydroxamic acids, 2,4-dihydroxy-7-methoxy-1,4-benzoxazin -3-one (DIMBOA), 6-methoxybenzoxazolinone (MBOA), and 2,4-dihydroxy-1,4-ben zoxazin-3-one (DIBOA), were identified in the maize roots tested. DIMBOA co ncentration was quantified and ranged from 246.37 +/- 70.53 mu g to 91.84 /- 49.82 mu g DIMBOA per gram of root tissue. No significant difference was found among lines in D. v. virgifera larval development and survivorship.