BioOne.org will be down briefly for maintenance on 17 December 2024 between 18:00-22:00 Pacific Time US. We apologize for any inconvenience.
How to translate text using browser tools
27 December 2021 Influence of Posttreatment Irrigation Timings and Herbicide Placement on Bermudagrass and Goosegrass (Eleusine indica) Response to Low-Dose Topramezone and Metribuzin Programs
John R. Brewer, Jordan C. Craft, Shawn D. Askew
Author Affiliations +
Abstract

Immediate posttreatment irrigation has been proposed as a method to reduce hybrid bermudagrass [Cynodon dactylon (L.) Pers. × Cynodon transvaalensis Burtt Davy] phytotoxicity from topramezone. Immediate irrigation is impractical, because it would take a turfgrass sprayer 10 to 15 min to cover an average golf course fairway or athletic field. There is also insufficient evidence regarding how posttreatment irrigation, immediate or otherwise, influences mature goosegrass [Eleusine indica (L.) Gaertn.] control from topramezone or low-dose topramezone plus metribuzin programs. We sought to investigate bermudagrass and E. indica response to immediate, 15-min, and 30-min posttreatment irrigation compared with no irrigation following topramezone at 12.3 g ae ha–1, the lowest labeled rate, or topramezone at 6.1 g ha–1 plus metribuzin at 210 g ai ha–1. We also evaluated placement of each herbicide and their combination on soil, foliage, and soil plus foliage to help elucidate the mechanisms involved in differential responses between species and herbicide mixtures. Responses were largely dependent on trial due to bermudagrass injury from high-dose topramezone being nearly eliminated by immediate irrigation in one trial and only slightly affected in another. When posttreatment irrigation was postponed for 15 or 30 min, topramezone alone injured bermudagrass unacceptably in both trials. Bermudagrass was injured less by low-dose topramezone plus metribuzin than by high-dose topramezone. All posttreatment irrigation timings reduced E. indica control compared with no posttreatment irrigation. The herbicide placement study suggested that topramezone control of E. indica is highly dependent on foliar uptake and that phytotoxicity of both bermudagrass and E. indica is greater from topramezone than metribuzin. Thus, posttreatment irrigation likely reduces topramezone rate load with a concomitant effect on plant phytotoxicity of both species. Metribuzin reduced 21-d cumulative clipping weight and tiller production of plants, and this may be a mechanism by which it reduces foliar white discoloration from topramezone.

© The Author(s), 2021. Published by Cambridge University Press on behalf of the Weed Science Society of America.
John R. Brewer, Jordan C. Craft, and Shawn D. Askew "Influence of Posttreatment Irrigation Timings and Herbicide Placement on Bermudagrass and Goosegrass (Eleusine indica) Response to Low-Dose Topramezone and Metribuzin Programs," Weed Science 70(2), 235-242, (27 December 2021). https://doi.org/10.1017/wsc.2021.80
Received: 7 September 2021; Accepted: 8 December 2021; Published: 27 December 2021
KEYWORDS
‘Latitude 36’
Days over injury threshold
digital image analysis
foliar- or soil-applied herbicide
late-season rescue treatments
turfgrass
white discoloration
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top