Response of Miscanthus Sinensis Transplants to Preemergence Herbicides.

Greenhouse experiments were conducted in the winter of 2008 to evaluate the response of Miscanthus sinensis transplants to preemergence herbicides. Herbicides were applied 2 days prior to transplant of plugs (5-leaf stage) into 3.8 liter pots filled with a Brownfield Sandy Clay Loam (loamy, mixed, superactive, thermic Arsenic Aridic Paleustalfs). Fertilizer (16N-10.5P-9.9K) was applied at time of transplant at a rate of 24.4 kg N/ha. Irrigation was applied through an automated irrigation system throughout the study to ensure optimal growth and prevent wilt stress. Pots were maintained weed free by hand weeding in order to eliminate plant competition. Nine herbicide treatments and a non-treated control were examined. Treatments were applied using a CO₂ backpack sprayer equipped with XR8002VS nozzle tips and calibrated to deliver 187 L/ha at 220 kPa. Preemergence herbicide treatments consisted of pendimethalin at 2 pt/A, metolachlor at 1.26 pt/A, acetochlor + atrazine at 1 qt/A, mesotrione at 6 oz/A, imazethapyr at 2.5 pt/A, sulfentrazone at 5.3 oz/A, metribuzin at 4.5 oz/A, clomazone at 2 pt/A, and dicamba at 1 pt/A. The trial was arranged in a randomized complete block design with 5 replications. Percent phytotoxicity was assessed visually 3, 5, 7, 14, 21, and 28 days after transplant (DAT) using a scale of 0 (no phytotoxicity) to 100% (plant death). Data were subjected to analysis of variance and means were separated using Fisher’s Protected LSD at the 0.05 significance level.