Essential oil composition of ‘WW-B.Dahl’ old world bluestem (Bothriochloa bladhii) grown in the Texas High Plains

Bothriochloa spp. include aromatic grasses that produce essential oils. Some of these grasses are reported to repel economically important insects. Leaves, stems, and seedheads of ‘WW-B.Dahl’ old world bluestem [Bothriochloa bladhii (Retz) S.T. Blake] were sampled during 3 years. Quantitative analysis by GC and GC–MS methods revealed a total of 172 compounds from methylation method, and 105 compounds from steam distillation method. Acorenone-B [spiro[4.5]dec-6-en-8-one, 1,7-dimethyl-4-(1-methylethyl)-] was in greatest concentration in both methods; however, this compound was detected on only one date (12 August) out of three collection dates extracted by steam distillation. Twenty-two compounds were detected by simple solvent extraction, in which acorenone-B was in greatest concentration in seedheads and least in stems. Diethylhexyl adipate was in highest concentration in stems and least in seedheads among the oils extracted by simple solvent. Camphene and limonene were present in the samples that contained seedheads. Naphthalene, a known insect deterrent, was detected in oils extracted from all methods and in all plant parts. Old world bluestem grass contained measurable amounts of essential oils that may be associated with previously observed repellency of red imported fire ants (Solenopsis invicta Buren).