New herbicides and tank mixes for control of waterhyacinth in the Sacramento–San Joaquin Delta

The Sacramento-San Joaquin Delta is the largest freshwater estuary on the West Coast of the United States. Delta habitat and economic utility are compromised by waterhyacinth, a floating aquatic weed. Standard control measures for waterhyacinth include foliar treatment with glyphosate or 2,4-D. We h...

Full description

Saved in:
Bibliographic Details
Published inJournal of aquatic plant management Vol. 59; pp. 78 - 81
Main Authors Kyser, Guy B, Madsen, John D, Miskella, John, O'Brien, Jon
Format Journal Article
LanguageEnglish
Published Gainesville Aquatic Plant Management Society, Inc 01.01.2021
Subjects
2,4-D
Additives
Aquatic plants
Aquatic weeds
Biomass
Crops
Deltas
Estuaries
Estuarine dynamics
Floating
Foliar applications
Freshwater
Glyphosate
Herbicides
Inland water environment
Nonnative species
Rice
Weeds
Sacramento California
United States > US
California
Sacramento-San Joaquin Delta
Online AccessGet full text

Cover

More Information
Summary:The Sacramento-San Joaquin Delta is the largest freshwater estuary on the West Coast of the United States. Delta habitat and economic utility are compromised by waterhyacinth, a floating aquatic weed. Standard control measures for waterhyacinth include foliar treatment with glyphosate or 2,4-D. We have conducted trials over three seasons to evaluate efficacy of newly registered, low-userate aquatic herbicides. In 2017, we evaluated waterhyacinth control using carfentrazone (133 g ai ha-1), flumioxazin (322 g ai ha-1), imazamox (280 g ae ha-1), and florpyrauxifen-benzyl (29.4 and 58.8 g ai ha-1), as well as various tank mixes, compared with a standard rate of glyphosate (1,681 g ae ha-1). Plots were established in floating 1-m2 quadrats, and treatments were replicated four times. All treatments were applied in 935 L ha-1 solution with 3.5 L ha-1 nonionic surfactant. We also included treatments with glyphosate (1,681 g ae ha-1) in lower spray volumes of 234 and 468 L ha-1. We collected biomass samples at 8 wk after treatment (WAT). Three treatments reduced waterhyacinth biomass by > 95%: florpyrauxifen-benzyl (58.8 g ai ha-1), flumioxazin + imazamox (322 + 280 g ai/ae ha-1), and the 468 L ha-1 application of glyphosate (1,681 g ae ha-1). Tank mixes (flumioxazin + imazamox, carfentrazone + imazamox, carfentrazone + glyphosate, and flumioxazin + glyphosate) gave approximately additive control. Florpyrauxifen-benzyl and flumioxazin + imazamox may be effective alternatives to glyphosate for controlling waterhyacinth with reduced rates of active ingredient. Glyphosate applied in a spray volume of 468 L ha-1 produced better control than the same rate of glyphosate in 935 L ha-1, suggesting that spray-volume optimization may be a useful topic for future research.
ISSN:0146-6623