Imazapic

Imazapic is an imidazolinone herbicide. Imazapic is an inhibitor of acetolactate synthase, which inhibits branched-chain amino acid biosynthesis, thereby hindering protein synthesis and cell growth and exerting herbicidal activity. Imazapic exerts a lethal effect only on Phelipanche aegyptiaca that has already parasitically attached to tomato roots, and has no inhibitory effect on unattached broomrape seeds and seedlings. Imazapic can control weedy annual grasses, non-grass herbaceous plants, and downy brome, but can damage perennial forage grass species. Imazapic can be used in herbicide-related research^[1][2][3][4]. In Vitro:Imazapic (0-5000 ppb; 14 days) showed no inhibitory effect on seed germination or seedling vigor of host-unattached Phelipanche aegyptiaca in Petri dish assays^[2].
Imazapic exhibits similar K_d values across all tested soils, but the K_d value in Gadash farm soil is twice as high. Imazapic shows similar K_oc values across all tested soils, while the K_oc value in Eden farm soil is more than twice as low^[1]. In Vivo:Imazapic (210 g ae/ha; foliar application) reduced stem density and cover of Euphorbia esula in pasture plots and increased native grass and forb cover; combining Imazapic with 1 or 2 years of sheep grazing did not enhance Euphorbia esula control compared with Imazapic alone^[1].

Imazapic (1‑10 ppb; repeated soil drenching) reduced the number of inflorescences and aboveground fresh weight of Phelipanche aegyptiaca in a greenhouse potted tomato system; at concentrations above 5 ppb, it caused slight phytotoxicity symptoms in tomato plants, but did not significantly alter tomato fruit yield^[2].