Evaluation of Herbicides on the Establishment of Pearl Millet [Pennisetum glaucum (L.) R. Br.] x Napiergrass (Pennisetum purpureum Schumach.)

Pearl millet [Pennisetum glaucum (L.) R. Br.] x napiergrass (Pennisetum purpureum Schumach.) (PMN) hybrids have potential as a seeded, perennial bioenergy or forage crop. The PMN hybrid utilized in this study (PMN10TX13) was developed as an alternative to herbaceous bioenergy feed stocks that either require vegetative propagation, complicated planting strategies due to small seed size, or annual reseeding due to annual growth habit. However, PMN seedlings are impacted by competition from nearby weeds for water, nutrients, and sunlight during establishment. To date, there is limited agronomic information on strategies for effective establishment of weed-free PMN stands. The objective of this study was to develop herbicide response tests to determine the phytotoxic effects of selected pre-crop emergence (PRE) and post-crop emergence herbicides (POST) on the seeded establishment of PMN. Several herbicides with utility for weed free establishment of seeded PMN were successfully identified. Pre-emergent herbicides Balance Pro (isoxaflutole), Dual II (s-metolachlor,) Plateau (imazapic), and Permit (halosulfuron) were effective as long as sufficient rates of seed safener were used. Post-crop emergent herbicides Permit (halosulfuron), Prowl (pendimethalin), Banvel (dicamba), Aatrex (atrazine), AIM (carfentrazone-ethyl), Warrant (achetochlor), and Huskie (pyrasulfotole) were also found to be safe for use at the 5-7 leaf stage and beyond