Ground ivy is a stoloniferous, perennial weed that persists in lawn turf. With the widespread use of 2,4-D on turf sites, the development of 2,4-D–tolerant ground ivy is a possibility. Ground ivy populations showed a highly variable response to foliar 2,4-D application. Ground ivy from Nebraska (NE) was tolerant to 2,4-D, whereas Ohio (OH) ground ivy was susceptible. The 2,4-D–susceptible OH population absorbed 37% more foliar-applied 14C–2,4-D than the 2,4-D–tolerant NE population. Although OH and NE populations total translocation of applied 14C was similar and averaged 5%, the OH population translocated 42% more toward the apical meristem of the primary stolon than the NE population, primarily because of the OH population's higher 14C–2,4-D absorption. The variation in response to 2,4-D found between these two populations occurred after exposure of roots to 2,4-D, but the effect was less pronounced. These results suggest that the difference in foliar uptake may partially contribute to differences in response to 2,4-D between these two populations. Likewise, differences in acropetal translocation may contribute to the differential sensitivity of 2,4-D–tolerant and –susceptible ground ivy populations.
Nomenclature: 2,4-D; ground ivy, Glechoma hederacea L. #3 GLEHE.
Additional index words: Dose response, ecotype, herbicide, resistance, root uptake, tolerance.
Abbreviations: DAT, days after treatment; HAT, hours after treatment; LCO, lawn care operators; NE, Nebraska; OH, Ohio.