RESPONSE OF FOOD AND FORAGE CROPS TO SOIL-APPLIED IMAZAPYR

Greenhouse experiments were conducted to determine the persistence of imazapyr and the tolerance of a wide variety of bioassay plants to ima zapyr residues in central Texas soils. Eleven bioassay crops were plan ted in pots 1 d before and 2, 6, and 12 mo after imazapyr application at rates of 0 0.02, 0.04, 0.07, 0.14, 0.28, 0.56, and 1.12 kg ai ha(-1 ). Imazapyr was phytotoxic 12 mo after treatment to all crop plants in at least one rate. Forage grasses and herbs were highly susceptible t o imazapyr residual carryover damage, as was corn and cabbage. Bean an d squash were tolerant of imazapyr residues. No statistical difference s occurred in imazapyr phytotoxicity to corn grown in leached vs. nonl eached pots.