scholarly journals Response of Young Pecan Trees to Repeated Applications of Indaziflam and Halosulfuron

HortScience ◽  
2018 ◽  
Vol 53 (3) ◽  
pp. 313-317 ◽  
Author(s):  
Timothy L. Grey ◽  
Keith Rucker ◽  
Lenny Wells ◽  
Xuelin Luo

Pecan production in the southeastern United States has increased because of the worldwide demand for the nuts of this tree. Information about the effects of the residual herbicides indaziflam and halosulfuron on newly planted pecan trees was evaluated over time for 4 years on sandy loam soils. After winter pecan tree planting, multiple spring or autumn herbicide applications were applied to the same pecan trees in different experiments in consecutive years. Visual injury, height, and caliper diameter measurements were taken up to six times during the growing season. Regression analysis of treatments over time indicated no differences in pecan tree growth for indaziflam at 73 or 146 g a.i./ha or halosulfuron at 35 g a.i./ha applied up to six times in 3 years, or for indaziflam at 37, 73, or 146 g a.i./ha applied up to five times in 3 years, as compared with nontreated controls. This information will benefit growers seeking viable weed control options when establishing new groves to meet the increased worldwide demand for pecan nuts.

Weed Science ◽  
2016 ◽  
Vol 64 (4) ◽  
pp. 766-771 ◽  
Author(s):  
Timothy L. Grey ◽  
Keith Rucker ◽  
Theodore M. Webster ◽  
Xuelin Luo

Olive production in the southeastern United States has recently begun to increase from demand for locally produced virgin olive oil. With no established commercial production as a reference, information about the effects of indaziflam residual herbicide on newly established trees was evaluated over time for up to 3 yr on loamy sand soils. Multiple spring and autumn applications of indaziflam at different rates were applied to the same newly planted or 1-yr-old olive trees in different experiments in consecutive years. Visual injury, height, and caliper diameter measures were taken monthly during the growing season up to six times. Regression analysis of treatments over time indicated no differences in olive tree growth for plots treated with indaziflam at 38, 75, or 150 g ai ha–1 up to five times in 3 yr, compared with nontreated controls. This information will be beneficial as olive growers seek viable weed control options when establishing new groves in the region.


Weed Science ◽  
1996 ◽  
Vol 44 (3) ◽  
pp. 575-578 ◽  
Author(s):  
Barry J. Brecke ◽  
Piotr Tobola

Wild poinsettia is a serious weed in several crops, including peanut, grown in the southeastern United States. A study was conducted over 3 yr at Jay, FL, to characterize the growth and development of wild poinsettia grown from seed collected at Plains, GA; Marianna, FL; and Baton Rouge, LA. Seedlings from each selection were transplanted to the field and were grown either alone or in competition with peanut. Observations made throughout the growing season indicated that the Louisiana selection flowered later, grew to a larger size, produced more leaf area and biomass, and caused greater light attenuation and peanut yield reduction than the other two selections. The Georgia selection produced the smallest plants, least leaf area and biomass, and was least competitive with peanut. The Florida selection was intermediate for these parameters. Wild poinsettia dry biomass production was reduced by 78 to 83% when grown with peanut compared with monoculture wild poinsettia.


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.


1983 ◽  
Vol 63 (3) ◽  
pp. 687-693 ◽  
Author(s):  
K. I. N. JENSEN ◽  
E. R. KIMBALL ◽  
J. A. IVANY

The efficacy and relative persistence of dinitramine (N′,N′-diethyl-α,α,α-trifluoro-3,5-dinitrotoluene-2-4-diamine), ethalfluralin [N-ethyl-N-(2-methyl-2-propenyl)-2,6-dinitro-4(trifluoromethyl) benzenamine], and trifluralin (α,α,α -trifluoro-2,6-dinitro-N,N-diproply-p-toluidine) were studied in a series of field trials conducted on a Charlottetown fine sandy loam (P.E.I.) and on a Somerset loamy sand (N.S.). Phytotoxicity, as reflected by weed control and injury to the peas (Pisum sativum L.), was greater on the sandy soil and herbicide rates recommended for the region may reduce yields on light soil types. The margin of crop tolerance was also reduced in one year characterized by an extremely wet growing season. Under field conditions, there was little practical difference in weed control obtained with the three herbicides. Dinitramine and ethalfluralin were more persistent in the Somerset sand than in the Charlottetown sandy loam. The order of decreasing persistence was trifluralin>ethalfluralin>dinitramine, except in the Somerset sand where the persistence of ethalfluralin and trifluralin was similar. Significant detectable levels of all three herbicides remained 320 days after application.Key words: Processing peas, dinitramine, ethalfluralin, trifluralin, residue


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 ◽  
2002 ◽  
Vol 37 (1) ◽  
pp. 104-107 ◽  
Author(s):  
Eric Simonne ◽  
Nadia Ouakrim ◽  
Arnold Caylor

Potato (Solanum tuberosum L.) is often produced as a nonirrigated crop in the southeastern United States. This practice makes tuber yields dependent on rainfall pattern and amount. An irrigation scheduling method based on a water balance and daily class A pan evaporation (Ep) was evaluated during 1996 and 1998 on a Hartsells fine sandy loam soil for `Red LaSoda' potatoes. Planting dates were 9 and 7 Apr. in 1996 and 1998, respectively, and standard production practices were followed each year. The model tested was (13 DAH + 191) * 0.5 ASW = D DAH-1 + [Ep * (0.12 + 0.023 DAH - 0.00019 DAH2) - RDAH - IDAH], where DAH was days after hilling, ASW was available soil water (0.13 mm/mm), D was soil water deficit (mm), R was rainfall (mm), and I was irrigation (mm). Controlled levels of water application ranging between 0% and 200% of the model rate were created with drip tapes. Four and seven irrigations were scheduled in 1996 and 1998, respectively. For both years, no interaction between irrigation regime and nitrogen rate was observed. Irrigation rate significantly influenced total yield and marketable yield (R2 > 0.88, P < 0.01). Highest total yields occurred at 99% and 86% of the model rate in 1996 and 1998, respectively. These results show that supplementing rainfall with irrigation and controlling the amount of water applied by adjusting irrigation to actual weather conditions increased potato marketable yield. Over the 2-year period of the study, an average additional profit of $563/ha/year was calculated from costs and returns due to irrigation, suggesting that drip-irrigation may be economical for potato production.


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.


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.


1981 ◽  
Vol 46 (4) ◽  
pp. 909-916 ◽  
Author(s):  
D. Bruce Dickson

Larson's (1972) hypothesis that warfare during the Mississippian period in the Southeast was primarily a struggle over the fertile silt and sandy loam bottomland soils is summarized. This is then contrasted with Gibson's (1974) thesis that, at least in the Lower Mississippi Valley, warfare was caused by the "asymmetrical" nature of the kinship systems found there. Such systems led to status decline over several generations and forced individuals to attempt to offset the decline by achieving success in warfare. The Larson-Gibson dispute is essentially an ontological argument which pits the materialist's view of reality against that of the idealist. This dispute is compared to a similar one between Harris (1971, 1974, 1977, 1979) and Lizot (1977) concerning the explanation of Yamomamo warfare in South America. Following this, the basic material conditions of Mississippian warfare are suggested. The importance of mechanisms such as Gibson has proposed for understanding Mississippian warfare at the "tactical" level is recognized. Finally, primacy is given to Larson"s materialism at the "strategic" level.


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