Research Summary Abstract
Fiesta (Iron HEDTA) is a new herbicide currently labeled for post emergence broadleaf weed control on lawns (use on rights of way or non-crop areas), turf, golf courses, parks, playgrounds, cemeteries and athletic fields. Neudorff is interested in adding environmental horticulture crops to the Fiesta label. The IR-4 Project completed 146 crop safety trials on 83 environmental horticulture plant species / genera during 2016 to 2019. In these trials, 7 plant species / genera (Buxus sp., Calamagrostis acutiflora, Carex cherokeensis, Festuca glauca, Juniperus spp., Muhlenbergia capillaris and Taxus x media) exhibited no or minimal transient injury after application to either dormant or actively growing plants at all 3 rates in at least 3 trials. Six species / genera (Cotoneaster apiculatus, Heuchera spp., Hibiscus sp., Lagerstroemia indica, Ophiopogon sp. and Teucrium chamaedrys), where Fiesta was applied to actively growing plants, exhibited no phytotoxicity at 1X but did have some injury at 2X and 4X rates. Twenty species / genera exhibited significant phytotoxicity at even the lowest rate; in ten of these crops, Fiesta was applied to dormant plants.