Interaction of Prodiamine and Flumioxazin for Nursery Weed Control

2010 ◽  
Vol 24 (4) ◽  
pp. 504-509 ◽  
Author(s):  
Glenn Wehtje ◽  
Charles H. Gilliam ◽  
Stephen C. Marble

Both prodiamine and flumioxazin are used in the nursery production and landscape maintenance industries in the southeastern United States for preemergence weed control. Research was conducted to determine whether a tank mixture of these two herbicides would be more effective than either component applied alone. Prodiamine alone, flumioxazin alone, and a 72 : 28 (by weight) prodiamine–flumioxazin mixture were each applied at a series of rates to containers filled with a pine bark–sand substrate that is typical for nursery production in the southeastern United States. Our intent was to have a rate range that hopefully extended from ineffective to lethal for each treatment series. Subsequent to treatment, containers were overseeded with either large crabgrass, spotted spurge, or eclipta. Percent control was determined by comparing treated weed foliage fresh weight to that of the appropriate nontreated control at 6 and 12 wk after application. ANOVA followed by nonlinear regression was used to evaluate the interaction of prodiamine and flumioxazin when combined and to determine the rate of each treatment series required for 95% control (if applicable) for each of the three weed species. Results varied with weed species. The mixture was synergistic and more cost effective than either of the components applied alone in controlling spotted spurge. With respect to large crabgrass control, the mixture was additive and slightly more cost effective than the components. Eclipta could only be controlled with flumioxazin, and this control was antagonized by the addition of prodiamine.

2010 ◽  
Vol 24 (3) ◽  
pp. 356-360 ◽  
Author(s):  
Glenn Wehtje ◽  
Charles H. Gilliam ◽  
Stephen C. Marble

Glyphosate plus flumioxazin tank mixtures have become popular in the nursery production and landscape maintenance industries in the southeastern United States. Research was conducted to compare the efficacy of such a mixture relative to the components applied alone. Glyphosate, flumioxazin, and glyphosate plus flumioxazin (2 : 1, w/w) were applied POST in container trials to four weed species at a series of rates that ranged from no effect to death. Regression analyses revealed that control data from all three treatment series could be described by the four-parameter, log-logistic model. With respect to glyphosate and flumioxazin applied alone, analysis revealed that across all four species, a lower rate of flumioxazin was required for 90% control than of glyphosate. The rate of the mixture required for 90% control was generally intermediate to the components applied alone and ranged from 0.36 kg ha−1 for hairy bittercress to 1.52 kg ha−1 for eclipta. Glyphosate alone was more cost effective than either flumioxazin alone or the mixture for the POST-applied control of all four species. The popularity of the tank mixture might be the result of flumioxazin-based PRE activity that was not measured in this study.


2004 ◽  
Vol 22 (2) ◽  
pp. 106-112
Author(s):  
Caren A. Judge ◽  
Joseph C. Neal ◽  
Jerome B. Weber

Abstract Preemergence herbicides are applied as often as every eight to ten weeks in container nursery crop production in the southeastern United States. However, weeds often emerge before reapplication. Experiments were conducted to assess the minimum surface-applied doses and the in vitro concentrations of preemergence herbicides required to control susceptible weed species. Greenhouse and outdoor container experiments were conducted to determine surface-applied Treflan (trifluralin) doses required to control large crabgrass and perennial ryegrass. In the greenhouse, 0.8 to 1.1 kg ai/ha (0.7 to 1.0 lb ai/A) was necessary for 6 weeks control. Outdoors, 1.5 to 1.9 kg ai/ha (1.3 to 1.7 lb ai/A) was needed for control 3 weeks after treatment (WAT). However, 6 WAT, 2.6 to 3.4 kg ai/ha (2.3 to 3.0 lb ai/A) was required. Petri dish experiments were conducted to determine the aqueous concentrations of Gallery (isoxaben), Surflan (oryzalin), and Treflan required to control common nursery weeds including eclipta, hairy bittercress, large crabgrass and spotted spurge. The concentration required for 80% shoot inhibition (I80) ranged from 0.4 to 1.5 μg ai/mL for Gallery, 1.2 to 9.8 μg ai/mL for Surflan and 1.1 to 73.8 μg ai/mL for Treflan. The relative response of weeds to aqueous concentrations was consistent with reports from outdoor container efficacy trials.


1994 ◽  
Vol 34 (7) ◽  
pp. 1021 ◽  
Author(s):  
JE Hill ◽  
RJ Jr Smith ◽  
DE Bayer

Among temperate rice areas, the United States and Australia are most similar in climate and in the mechanisation of rice culture. Many weed problems, even weed species invading rice, are common to both countries; and the present technology for weed control as well as concern for the impact of these technologies to environmental quality, herbicide resistance, and other weed-related issues bear many similarities. Application of current, and any new, technologies to emerging issues in US rice weed control will therefore be directly relevant to rice production in Australia and all other temperate areas struggling with the same challenges. Weeds are a significant problem in temperate rice culture. In the United States, rice is mechanically direct-seeded, allowing weeds to germinate and establish with the crop. In the last 15 years weed growth and competition has been increased by the adoption of semi-dwarf cultivars, high N fertilisation, and, in water-seeded rice, shallow flooding. High rates, and often multiple applications, of herbicides have been necessary to maximise the yield potential of these cultural systems. Advances in cultural practices and herbicide technology have maintained, if not improved, weed control; but nearly 30 years of propanil use in the southern USA resulted in propanil-resistant barnyard grass Echinochloa crus-galli (L.) Beauv., and after 4 years of continuous use, bensulfuron resistance to 4 aquatic weed species was discovered in California. Although herbicides with different mechanisms of action are needed for alternation in resistance management strategies, fewer are likely to be available. Social and environmental concerns have slowed the development and registration of rice herbicides and increased the cost of controlling weeds. Water quality deterioration from ricefield tailwaters, drift to sensitive crops, the cost of renewing registration in aquatic systems, and weed resistance all forecast reduced herbicide use in rice. Neither cultural practices nor herbicides alone can solve weed problems in direct-seeded, mechanised rice culture. With fewer herbicides and a cultural system highly vulnerable to weed losses, integrated management strategies with better information on which to base weed control decisions will be needed to solve weed problems in temperate rice.


1994 ◽  
Vol 8 (1) ◽  
pp. 23-27 ◽  
Author(s):  
David L. Jordan ◽  
John W. Wilcut ◽  
Leslie D. Fortner

Field experiments conducted in 1988 and 1989 evaluated clomazone alone and in a systems approach for weed control in peanut. Clomazone PPI at 0.8 kg ai/ha controlled common ragweed, prickly sida, spurred anoda, and tropic croton better than ethalfluralin and/or metolachlor applied PPI. POST application of acifluorfen plus bentazon was not needed to control these weeds when clomazone was used. Acifluorfen plus bentazon improved control of these weeds when clomazone was not used and generally were necessary to obtain peanut yields regardless of the soil-applied herbicides. Alachlor PRE did not improve clomazone control of any weed species evaluated. Fall panicum and large crabgrass control was similar with clomazone or clomazone plus ethalfluralin.


2019 ◽  
Vol 29 (5) ◽  
pp. 571-577
Author(s):  
Suzanne P. Stone ◽  
George E. Boyhan ◽  
W. Carroll Johnson

The southeastern United States produces 50% of U.S. conventional watermelon (Citrullus lanatus) but only 7% of U.S. organic watermelon. Weeds are a major threat to watermelon yield in the southeastern United States, and organic weed control is estimated to cost 20-times more than conventional herbicide programs. The objectives of this study were to determine the optimal weed control regime to reduce hand-weeding costs while maintaining yield and to compare the weed suppression of two watermelon types with differing growth habits in an organic system. In 2014 and 2015, watermelon plots were randomly assigned to the following treatments in a factorial arrangement: vine or compact growth habit; 1.0- or 0.5-m in-row spacing; and weekly weed control (kept weed-free by hoeing and hand-pulling weeds) for 0, 4, or 8 weeks after transplanting (WAT). At the time of the watermelon harvest, not weeding resulted in average total weed densities of 86.6 and 87.0 weeds/m2, and weeding for 4 WAT resulted in average total weed densities of 26.4 and 7.0 weeds/m2 in 2014 and 2015, respectively. Nonetheless, weeding for 4 WAT resulted in watermelon yields and fruit counts comparable to those of weeding for 8 WAT during both years. This partial-season weeding regime resulted in 67% and 63% weeding cost reductions for vine and compact plants, respectively, in 2014, and a 43% reduction for both growth habit types in 2015. In 2015, a separate experiment that evaluated weeding regimes that lasted 0, 1, 2, 3, 4, and 8 WAT found that yields resulting from weeding for 3 WAT were greater than those resulting from weeding for 2 WAT. However, the yields did not differ when weeding was performed for 4 WAT and 8 WAT.


HortScience ◽  
2015 ◽  
Vol 50 (10) ◽  
pp. 1567-1571
Author(s):  
Timothy K. Broschat

Potassium (K) deficiency is a widespread problem in palms growing in sandy or calcareous soils in southeastern United States. Its symptoms are highly conspicuous, reduce palm aesthetic appeal, are difficult to correct, and can be exacerbated by nitrogen (N) fertilization. The objective of this study was to determine the optimum fertilization rates and ratio for N and K in areca palm [Dypsis lutescens (H. Wendl.) Beentje & J. Dransf. and Mexican fan palm (Washingtonia robusta H. Wendl.) growing in a calcareous sandy fill soil. Both species had their highest quality when fertilized with 12.2 g·m−2 N and 12.2 g·m−2 K from controlled-release (2–3 month release) sources every 3 months. Actual N and K application rates were better predictors of palm quality than N:K ratio at the highest fertilization rates that would be recommended for field nursery production. However, at lower application rates more typical of those used for landscape palm maintenance, palm quality improved as the N:K application ratio was decreased.


2018 ◽  
Vol 32 (6) ◽  
pp. 726-732
Author(s):  
W. Carroll Johnson ◽  
Theodore M. Webster ◽  
Timothy L. Grey ◽  
Xuelin Luo

AbstractSugarbeet, grown for biofuel, is being considered as an alternate cool-season crop in the southeastern United States. Previous research identified ethofumesate PRE and phenmedipham + desmedipham POST as herbicides that controlled troublesome cool-season weeds in the region, specifically cutleaf evening-primrose. Research trials were conducted from 2014 through 2016 to evaluate an integrated system of sweep cultivation and reduced rates of ethofumesate PRE and/or phenmedipham+desmedipham POST for weed control in sugarbeet grown for biofuel. There were no interactions between the main effects of cultivation and herbicides for control of cutleaf evening-primrose and other cool-season species in two out of three years. Cultivation improved control of cool-season weeds, but the effect was largely independent of control provided by herbicides. Of the herbicide combinations evaluated, the best overall cool-season weed control was from systems that included either a 1/2X or 1X rate of phenmedipham+desmedipham POST. Either rate of ethofumesate PRE was less effective than phenmedipham+desmedipham POST. Despite improved cool-season weed control, sugarbeet yield was not affected by cultivation each year of the study. Sugarbeet yields were greater when treated with any herbicide combination that included either a 1/2X or 1X rate of phenmedipham+desmedipham POST compared with either rate of ethofumesate PRE alone or the nontreated control. These results indicate that cultivation has a very limited role in sugarbeet grown for biofuel. The premise of effective weed control based on an integration of cultivation and reduced herbicide rates does not appear to be viable for sugarbeet grown for biofuel.


2020 ◽  
Vol 34 (6) ◽  
pp. 818-823 ◽  
Author(s):  
John M. Peppers ◽  
Clebson G. Gonçalves ◽  
J. Scott McElroy

AbstractPinoxaden is a POST acetyl coenzyme A carboxylase (ACCase) inhibitor in the phenylpyrazolin chemical family and is labelled for turfgrass use at broadcast rates of 35.5 to 71 g ai ha−1 and spot spray rates of 156 to 310 g ai ha−1. A greenhouse rate-response study was conducted to characterize the efficacy of pinoxaden against common grassy weeds. Weed species examined in this study were yellow foxtail, southern sandbur, annual bluegrass, roughstalk bluegrass, large crabgrass, dallisgrass, bahiagrass, goosegrass, and perennial ryegrass. Nonlinear regressions were modelled to determine visible injury rates (the application rate at which 50% of the weed species were injured and the 90% [I90] rate) and weight reduction rates (the application rate at which there was a 50% reduction in fresh weight and 90% reduction [WR90]) for each weed species. Only annual bluegrass, bahiagrass, and goosegrass had visible injury I90 values greater than the maximum labelled spot spray rate of 310 g ai ha−1. Annual bluegrass, bahiagrass, southern sandbur, and goosegrass all had WR90 values greater than the maximum labelled spot spray rate of 310 g ai ha−1. Results from this study indicate that the evaluated weed species can be ranked, according to visible injury I90 values, from most to least susceptible: perennial ryegrass > yellow foxtail > dallisgrass > large crabgrass > southern sandbur > roughstalk bluegrass > bahiagrass > goosegrass > annual bluegrass.


Weed Science ◽  
1973 ◽  
Vol 21 (4) ◽  
pp. 363-366 ◽  
Author(s):  
T. R. Dill ◽  
M. C. Carter

Weed control trials were conducted on loblolly pine (Pinus taedaL.) or slash pine (Pinus elliottiiEngelm.) seedbeds at 12 locations in the southeastern United States. Good weed control was obtained from 2,4-bis-(isopropylamino)-6-(methylthio)-s-triazine (prometryne) at 2.2 and 4.5 kg/ha;N,N-dimethyl-2,2-diphenylacetamide (diphenamid) at 4.5 and 9 kg/ha; α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) at 1.1 and 2.2 kg/ha; and 2-ethylthio-4,6-bis-isopropylamino-s-triazine (GS-16068) at 2.2 and 4.5 kg/ha as preemergence applications immediately followed by irrigation. Diphenamid and trifluralin treatments were not injurious to either pine species at either rate. GS-16068 was only slightly injurious at the high rate at one location. Prometryne was injurious at two locations at the high rate and at one location at the low rate.


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