Interactive effects of diluent pH and calcium content on glyphosate activity on <i>Panicum repens</i> L. (torpedograss)

Shilling, Donn G.; Haller, William T.

doi:10.1111/j.1365-3180.1989.tb01316.x

Cited by 28 publications

(22 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Glyphosate, an effective chelator of ions in solution (Glass 1984;O'Sullivan et al 1981), is affected by naturally occurring ions in carrier water. Calcium, iron, zinc, aluminum, and magnesium cations generally antagonize glyphosate activity (Buhler and Burnside 1983;Hatzios and Penner 1985;Sandberg et al 1978;Shillevg and Waller 1989). Cation antagonism of glyphosate occurred with iron Ͼ zinc Ͼ calcium Ն magnesium Ͼ sodium Ͼ potassium (Nalewaja and Matysiak 1991).…”

Section: Introductionmentioning

confidence: 99%

Comparison of Glyphosate Salts (Isopropylamine, Diammonium, and Potassium) and Calcium and Magnesium Concentrations on the Control of Various Weeds

et al. 2006

View full text Add to dashboard Cite

Greenhouse and field experiments were conducted near Knoxville, TN, during 2002 and 2003 to investigate the effects of calcium and magnesium ions on the performance of three glyphosate formulations with and without diammonium sulfate (AMS). Weed species investigated in the greenhouse were broadleaf signalgrass, pitted morningglory, Palmer amaranth, and yellow nutsedge. Three glyphosate formulations (isopropylamine salt, diammonium salt, and potassium salt) and two glyphosate application rates (0.42 and 0.84 kg ae/ha) were applied to weeds in water fortified with either calcium or magnesium at concentrations of 0, 250, 500, 750, and 1,000 ppm. In all comparisons, there were no differences in the three glyphosate formulations. Glyphosate activity was reduced only when cation concentration was >250 ppm, and this antagonism was not observed when 2% w/ w AMS was added to the spray solution. A chemical analysis of the calcium and magnesium concentrations in water collected from farmers indicated that water samples from eight different producers contained relatively low amounts of cations, with calcium at <40 ppm and magnesium at <8 ppm. In the field results using these and other waters as the herbicide carrier, broadleaf signalgrass control was greater with the 0.84 kg ae/ha than 0.42 kg ae/ha glyphosate rate regardless of water source or addition of AMS. Pitted morningglory responded similarly to glyphosate with water from all farms and with AMS added, and the addition of AMS gave similar results for both glyphosate rates. In 2003, common cocklebur was evaluated and control was >93% regardless of glyphosate rate, water source, or AMS addition. Based on these results, the addition of AMS-based adjuvants to many glyphosate applications may not be warranted.

show abstract

Section: Introductionmentioning

confidence: 99%

Comparison of Glyphosate Salts (Isopropylamine, Diammonium, and Potassium) and Calcium and Magnesium Concentrations on the Control of Various Weeds

et al. 2006

View full text Add to dashboard Cite

show abstract

“…On the other hand, the influence of the pH on glyphosate's efficiency was better investigated. Previous studies had demonstrated that glyphosate's activity is higher in acidic pH than that in alkaline [23][24][25]. Shea and Tupy [23] observed that the increase of the glyphosate solution pH from 4 to 5.5 was sufficient to reduce its efficiency on weed control, but no significant difference was resultant due to the adjustment of the pH from 5.5 to 6 or 10.…”

Section: Monitoring the Ph And Electric Conductivitymentioning

confidence: 99%

Understanding the chemistry of manganese fertilizers and glyphosate mixtures by using synchrotron X-ray spectrometry

et al. 2020

View full text Add to dashboard Cite

The spraying of tank mixtures with manganese (Mn) and glyphosate is a practical alternative to alleviate nutritional deficiency while controlling weeds. Thereby, this study investigates the chemical interactions between glyphosate and commercial sources of Mn, such as MnSO 4 , Mn-phosphite, Mn-EDTA, Mn-glycine, and MnCO 3. Nearly 30% of the Mn supplied as MnSO 4 and Mn-glycine precipitated with glyphosate, yielding a Mn:glyphosate solid complex with molar ratio of nearly 2:1, both presenting similar chemical environment. XANES analysis of the supernatants indicate no formation of Mn-glyphosate soluble complexes. The use of Mn-EDTA as well as the maintenance of the mixture pH below 2.5 prevented precipitation, while pH above 7 caused the formation of MnO(OH). In conclusion, the Mn source and the pH of the mixtures matter. The absence of Mn-glyphosate soluble complexes suggests that dissolved Mn and glyphosate are still able to accomplish their functions, however, the precipitation significantly decreases their active availability.

show abstract

“…Although torpedograss is rooted in the littoral zone, the species often forms dense floating mats that extend across the surface of the water, thus blocking light and oxygen penetration in a manner similar to that of water hyacinth, crested floatingheart, and canopy-forming hydrilla. Torpedograss also outcompetes most native littoral zone species, resulting in monocultures that provide poor habitats for aquatic fauna (Shilling and Haller, 1989).…”

Section: Littoral Exotic Invasive Plant: Torpedograss (Panicum Repens)mentioning

confidence: 99%

Breaking Bad: Native Aquatic Plants Gone Rogue and the Invasive Species That Inspire Them

Gettys

2019

hortte

View full text Add to dashboard Cite

Conventional wisdom suggests that native aquatic plants have evolved to fill a specific ecological niche, and that their growth is regulated by environmental conditions or the presence of natural enemies that limit the distribution or abundance of the species. However, it is becoming obvious that native species are not always well-behaved and can develop populations that quickly reach nuisance levels that require management to avoid negative ecological impacts. This work summarizes information presented at the American Society for Horticultural Science Invasive Plants Research Professional Interest Group Workshops in 2017 and 2018, and it highlights the phenomenon of species that are considered both native and invasive in the aquatic ecosystems of Florida. These “natives gone rogue” are compared with the introduced species they mimic, and the consequences of excessive aquatic plant growth, regardless of the origin of the species, are described.

show abstract

Interactive effects of diluent pH and calcium content on glyphosate activity on Panicum repens L. (torpedograss)

Cited by 28 publications

References 19 publications

Comparison of Glyphosate Salts (Isopropylamine, Diammonium, and Potassium) and Calcium and Magnesium Concentrations on the Control of Various Weeds

Comparison of Glyphosate Salts (Isopropylamine, Diammonium, and Potassium) and Calcium and Magnesium Concentrations on the Control of Various Weeds

Understanding the chemistry of manganese fertilizers and glyphosate mixtures by using synchrotron X-ray spectrometry

Breaking Bad: Native Aquatic Plants Gone Rogue and the Invasive Species That Inspire Them

Contact Info

Product

Resources

About