Submitted to: Subtropical Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 10, 1999
Publication Date: N/A
Interpretive Summary: Early season weed competition can reduce kenaf growth and stalk yield. Application method and dosage level of five herbicides were evaluated for control of Texas panicum and Palmer amaranth, kenaf phytotoxicity, and effect on stalk yield. Trifluralin, pendimethalin, metolachlor, were applied either pre-plant incorporated or preemergence at two dosage levels. MSMA and fluazifop-P-butyl were applied postemergence at one or two sequential timings at two dosage levels. Only pre-plant incorporated treatments of trifluralin at 1.1 kg ha**-1 and pre-plant incorporated or preemergence applied pendimethalin treatments applied at 1.1 or 2.2 kg ha**-1 effectively controlled weed species present, had very little phytotoxic effects on kenaf and did not adversely affect kenaf stalk yield. Results of this study indicate that trifluralin or pendimethalin can effectively be used in the Rio Grande Valley of Texas to control early season weeds in kenaf without adverse effects on stalk yield.
Technical Abstract: Early season weed competition in kenaf can reduce stand establishment and stalk yield. The objectives of this study were to identify herbicides for early season weed control in kenaf which would not be phytotoxic to kenaf but would control early season weeds primarily, Panicum texanum L. and Amaranthus palmeri. L., two of the most common and troublesome weeds in the Lower Rio Grande Valley. Sixteen herbicide treatments with five different herbicides were applied to kenaf either pre-plant incorporated (PPI), preemergence (PRE), or postemergence (POST). Dosage level and timing of herbicide applications for trifluralin, pendimethalin, metolachlor, MSMA, and fluazifop-P-butyl were also examined. Kenaf stalk yield was largest with trifluralin applied PRE at 1.1 kg ha**-1 and all of the pendimethalin treatments (either PPI or PRE). Pendimethalin treatments also produced the greatest plant heights. All other treatments had a reduced stalk yield. Greatest weed control, least herbicide phytotoxicity to kenaf, and greatest kenaf stalk weight were achieved with treatments of trifluralin applied at 1.1 kg ha**-1, or pendimethalin applied either PPI or PRE at 1.1 or 2.2 kg ha**-1. Results of this study indicate that trifluralin and pendimethalin can be used effectively for early season weed control in kenaf without adverse affects on crop development or yield.