Seasonal Response of Woody Plants to Tebuthiuron Pellets

Weed Science ◽  
1985 ◽  
Vol 33 (4) ◽  
pp. 551-554 ◽  
Author(s):  
Rodney W. Bovey ◽  
Robert E. Meyer ◽  
L. Fred Bouse ◽  
James B. Carlton

Pelleted tebuthiuron {N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N′-dimethylurea} was hand broadcast at 2.2 and 4.5 kg ai/ha every month for 2 yr on an area infested with live oak (Quercus virginianaMill. ♯4QUEVI), post oak (Q. stellataWangenh. ♯ QUESL), parsley hawthorn (Crataegus marshalliiEgglest. ♯ CSCMS), and yaupon (Ilex vomitoriaAit. ♯ ILEVO) on the Gulf Coast Prairie near Cordele, TX. Live oak, post oak, and parsley hawthorn trees were killed at most rates and dates of tebuthiuron application. Applications of 2.2 kg/ha of tebuthiuron killed 90% or more of the yaupon plants when it was applied in October and December 1975 and February, March, and June 1976 and less than 90% when applied at other dates. On another site, pelleted tebuthiuron was aerially applied at 2.2 and 4.5 kg/ha every 3 months during 1978 and 1979 in the Post Oak Savannah near Bryan, TX. At 2.2 kg/ha, tebuthiuron killed all post oak and 80% or more of the blackjack oak (Q. marilandicaMuechh.), yaupon, winged elm (Ulmus alataMichx. ♯ ULMAL), and mockernut hickory (Carya tomentosaNutt.) regardless of date treated. Tree huckleberry (Vaccinium arboreumMarsh.) killed by tebuthiuron when applied at 2.2 kg/ha ranged from 34% in July 1979 to 69% from application in February 1978. Application of 4.5 kg/ha of tebuthiuron killed 83% or more of the tree huckleberry when it was applied in January and April 1978 and January, April, July, and October 1979. Herbaceous plant cover usually increased by the second season.

Weed Science ◽  
1980 ◽  
Vol 28 (3) ◽  
pp. 358-362 ◽  
Author(s):  
R. E. Meyer ◽  
R. W. Bovey

Hexazinone [3-cyclohexyl-6-(dimethylamino)-1-methyl-1,3,5-triazine-2,4(1H,3H)-dione] was applied to honeylocust (Gleditsia triacanthosL.), honey mesquite [Prosopis juliflora(Swartz) DC. var.glandulosa(Torr.) Cockerell], huisache [Acacia farnesiana(L.) Willd.], live oak (Quercus virginianaMill.), Macartney rose (Rosa bracteataWendl.), post oak (Quercus stellataWangenh.), saw greenbrier (Smilax bona-noxL.), whitebrush (Aloysia lycioidesCham.), and yaupon (Ilex vomitoriaAit.). Bromacil (5-bromo-3-sec-butyl-6-methyluracil) and tebuthiuron {N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N′-dimethylurea} were used for comparison in some experiments. Hexazinone was required at the following rates to kill at least 75% of the following species: 1.1 kg/ha for live oak, 2.2 kg/ha for post oak, 4.5 kg/ha for huisache (at Bryan, Texas) and whitebrush, and 9 kg/ha for honeylocust. Hexazinone was ineffective at 9 kg/ha for control of honey mesquite, huisache (at Washington, Texas), Macartney rose, saw greenbrier, and yaupon. Tebuthiuron at 1.1 kg/ha killed 80% of the live oak, and as a subsurface spray at 4.5 kg/ha, killed huisache (at Washington, Texas). Bromacil was effective on huisache at 9 kg/ha.


Weed Science ◽  
1982 ◽  
Vol 30 (4) ◽  
pp. 378-384 ◽  
Author(s):  
Robert E. Meyer

Soil-applied herbicides were evaluated for control of blackjack oak (Quercus marilandicaMuenchh.), huisache [Acacia farnesiana(L.) Willd.], honey mesquite [Prosopis juliflora(Swartz) DC. var.glandulosa(Torr.) Cockerell], live oak (Quercus virginianaMill.), Macartney rose (Rosa bracteataWendl.), winged elm (Ulmus alataMichx.), and yaupon (Ilex vomitoriaAit.) in Texas. Various spacing of spot treatments of pelleted tebuthiuron {N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N′-dimethylurea} on huisache and live oak and picloram (4-amino-3,5,6-trichloropicolinic acid) on Macartney rose up to a 2.7-m square grid did not change herbicide effectiveness. Pelleted tebuthiuron at 2.2 kg/ha reduced the canopy of live oak and killed a significant percentage of plants; however, differences among herbicide formulations and distance of placement in a grid were small. On unburned plots, 2.2 kg/ha of tebuthiuron applied as pellets at 2.7-m centers and as a broadcast wettable-powder treatment killed fewer yaupon than pellets applied in most broadcast treatments. In individual-plant treatments, bromacil (5-bromo-3-sec-butyl-6-methyluracil) and picloram solutions at 2 g/plant killed 45% of the yaupon 1.5 to 2 m tall on a fine sandy loam, whereas 0.5 g/plant of either herbicide killed 70% or more of the yaupon plants 1 m tall on a loamy fine sand. Both bromacil and picloram at 1 g/plant killed all blackjack oak and winged elm sprouts 1 to 2 m tall. On a clay soil, 1 g of bromacil/plant killed 79% of the live oak and 88% of the winged elm plants, whereas picloram killed only 38 and 45%, respectively. Neither bromacil nor picloram was effective as soil treatments for killing honey mesquite.


Weed Science ◽  
1969 ◽  
Vol 17 (4) ◽  
pp. 538-541 ◽  
Author(s):  
R. W. Bovey ◽  
H. L. Morton ◽  
J. R. Baur ◽  
J. D. Diaz-Colon ◽  
C. C. Dowler ◽  
...  

Granular 4-amino-3,5,6-trichloropicolinic acid (picloram) was effective in controlling live oak(Quercus virginiana(Mill.), huisache)(Acacia farnesiana(L.), Willd.), and yaupon(Ilex vomitoriaAit.), but not honey mesquite(Prosopis juliflora(Swartz) DC. var.glandulosa(Torr.) Cockerell) in south Texas. Granular 5-bromo-3-sec-butyl-6-methyluracil (bromacil) controlled live oak and huisache. Herbicides applied to soil were usually most effective in spring and fall during periods of active brush growth. Picloram granules applied in May to a mixed stand of woody plants in Puerto Rico usually were effective. However, rates up to 30 lb/A were ineffective on some species.


Weed Science ◽  
1972 ◽  
Vol 20 (4) ◽  
pp. 332-335 ◽  
Author(s):  
R. W. Bovey ◽  
R. E. Meyer ◽  
R. D. Baker ◽  
J. R. Baur

Polymerized and conventional (2,4-dichlorophenoxy)-acetic acid (2,4-D), (2,4,5-trichlorophenoxy)acetic acid (2,4,5-T), 3,6-dichloro-o-anisic acid (dicamba), and 4-amino-3,5,6-trichloro-picolinic acid (picloram) were applied alone and in certain combinations to several brush species. Generally there were no significant differences in effectiveness between conventional and polymerized herbicides on honey mesquite(Prosopis juliflora(Swartz) DC. var.glandulosa(Torr.) Cockrell), huisache(Acacia farnesianaL. Willd.), Macartney rose(Rosa bracteataWendl.), live oak(Quercus virginianaMill.), whitebrush(Aloysia lycioidesCham.), and winged elm(Ulmus alataMichx.). Conventional granular picloram was more effective on yaupon(Ilex vomitoriaAit.) than polymerized formulations.


Weed Science ◽  
1970 ◽  
Vol 18 (4) ◽  
pp. 447-451 ◽  
Author(s):  
R. W. Bovey ◽  
M. L. Ketchersid ◽  
M. G. Merkle

Under Texas conditions, the potassium salt of 4-amino-3,5,6-trichloropicolinic acid (picloram) usually was more effective than the isooctyl ester formulation for control of live oak (Quercus virginianaMill.), yaupon(Ilex vomitoriaAit.), winged elm(Ulmus alataMichx.), huisache (Acacia farnesiana(L.) Willd.), and honey mesquite(Prosopis juliflora(Swartz) DC. var.glandulosa(Torr.) Cockerell). Possible reasons for the difference in effectiveness of picloram formulations were studied in the laboratory. Extensive degradation of the ester of picloram (96%) occurred in open Petri dishes after 72 hr exposure to ultraviolet (uv) light, compared to a loss of 26% for the salt of picloram. Forty-five percent of the isooctyl ester of picloram was lost at high temperatures (60 C), whereas only 2% of the potassium salt of picloram was lost after 1 week at 60 C from open Petri dishes in a dark oven. Application of the ester to soils reduced thermal and ultraviolet light degradation losses compared to losses from open Petri dishes. Loss of the ester was greater when applied in diesel oil to Petri dishes than in either water or paraffin oil. The salt of picloram leached most after 12.5 cm simulated rainfall in soil columns to the 17.5 to 30-cm level (907 μg), followed by the acid (360 μg), and last the isooctyl ester (0 μg). However, considerable acid (161 μg) was recovered at the 32.5 to 45-cm depth from the isooctyl ester treatment exposed to wet soils for 3 days, indicating hydrolysis of the ester to acid.


Weed Science ◽  
1981 ◽  
Vol 29 (3) ◽  
pp. 270-275 ◽  
Author(s):  
C. J. Scifres ◽  
J. W. Stuth ◽  
R. W. Bovey

Aerial applications of 20% tebuthiuron {N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N-dimethylurea} pellets at 2.2 kg/ha (ai) in the spring effectively controlled post oak (Quercus stellataWangenh.), blackjack oak (Q. marilandicaMuenchh.), water oak (Q. nigraL.), yaupon (Ilex vomitoriaAit.), winged elm (Ulmus alataMichx.), downy hawthorn (Crataegus mollisScheele), gum bumelia [Bumelia lanuginosa(Michx.) Pers.], and willow baccharis (Baccharis salicinaTorr. & Gray) in the Post Oak Savannah of Texas. Tree huckleberry (Vaccinium arboreumMarsh.), black hickory (Carya texanaBuckl.), honeylocust (Gleditsia triachanthosL.) and cedar elm (Ulmus crassifoliaNutt.) were partially controlled by 2.2 kg/ha of tebuthiuron. Canopies of buckbrush (Symphoricarpos orbiculatusMoench), southern dewberry (Rubus trivialisMichx.), American beautyberry (Callicarpa americanaL.), and persimmon (Diospyros virginianaL.) were reduced for about two growing seasons after which the woody species recovered. American beautyberry appeared to increase in abundance by the third growing season after control of the other woody species. Honey mesquite [Prosopis juliflora(Swartz) DC. var.glandulosa(Torr.) Cockerell], eastern redcedar (Juniperus virginianaL.), and Texas persimmon (Diospyros texanaScheele) were not controlled by tebuthiuron at 2.2 or 4.4 kg/ha, and saw greenbrier (Similax bona-noxL.) and peppervine [Ampelopsis arborea(L.) Koehne] apparently increased following application of tebuthiuron.


Weed Science ◽  
1973 ◽  
Vol 21 (5) ◽  
pp. 423-426 ◽  
Author(s):  
R. E. Meyer ◽  
R. W. Bovey

Honey mesquite [Prosopis juliflora(Swartz) DC. var.glandulosa(Torr.) Cockerell], huisache [Acacia farnesiana(L.) Willd.], Macartney rose (Rosa bracteataWendl.), live oak (Quercus virginianaMill.), and whitebrush (Aloysia lycioidesCham.) were sprayed with herbicides alone and in mixtures. Mixtures of picloram (4-amino-3,5,6-trichloropicolinic acid) + dicamba (3,6-dichloro-o-anisic acid) at 0.56 + 0.56 and 1.12 + 1.12 kg/ha were most effective for killing honey mesquite in July. Picloram or picloram + dicamba were more effective for defoliating huisache than 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid], dicamba, or other mixtures of herbicides. On Macartney rose picloram as the salt or ester was most effective, but some mixtures of picloram plus either 2,4-D [(2,4-dichlorophenoxy)acetic acid] or 2,4,5-T were as effective as picloram alone. On live oak, the most effective treatments generally contained at least 1.12 kg/ha of picloram either alone or in mixtures with dicamba or 2,4,5-T. Picloram alone killed as many or more whitebrush plants than MCPA [[(4-chloro-o-tolyl)oxy]acetic acid], dicamba, 2,4,5-T, 2,4-D, or mixtures.


Weed Science ◽  
1968 ◽  
Vol 16 (3) ◽  
pp. 332-335 ◽  
Author(s):  
R. W. Bovey ◽  
F. S. Davis ◽  
H. L. Morton

We studied 4-amino-3,5,6-trichloropicolinic acid (picloram) alone and in combination with 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) or 1,1′-dimethyl-4,4′-bipyridinium salt (paraquat) for control of several greenhouse, nursery, and natural-grown, woody plant species. Picloram:paraquat combinations improved the control of some species such as yaupon (Ilex vomitoria Ait.) as compared to picloram alone at equal rates; but it had an antagonistic effect on huisache (Acacia farnesiana (L.) Willd.) and honey mesquite (Prosopis juliflora (Swartz) DC. var. glandulosa (Torr.) Cockerell). Evaluation of picloram: 2,4,5-T combinations suggested that 2,4,5-T sometimes could be added in equal amounts to picloram to increase control or reduce picloram rates proportionately on huisache, honey mesquite and live oak (Quercus virginiana Mill.).


Weed Science ◽  
1978 ◽  
Vol 26 (2) ◽  
pp. 139-144 ◽  
Author(s):  
C. J. Scifres ◽  
J. L. Mutz ◽  
C. H. Meadors

Karbutilate [tert-butylcarbamic acid ester with 3(m-hydroxypheny)-1, 1-dimethylurea], formulated as a ball 1.34 cm in diameter, was applied to brush-infested rangeland with fixed-wing aircraft and in a grid pattern by hand at an average density of four balls/12.4 m2 (1.83-m spacing). Control of woody plants with karbutilate applied by hand in an exact grid pattern was not different from aerial applications at the same rate. Based on evaluations at least 24 months after application, karbutilate at 0.56 or 1.12 kg/ha did not control honey mesquite [Prosopis juliflora (Swartz) DC. var. glandulosa (Torr.) Cockerell] in the subhumid Post Oak Savannah or semiarid Rolling Plains of Texas. At 2.24 kg/ha, canopy reduction of honey mesquite averaged 70% with 20 to 25% of the population killed. Post oak (Quercus stellata Wangenh.), blackjack oak (Quercus marilandica Muenchh.), yaupon (Ilex vomitoria Ait.), or winged elm (Ulmus alata Michx.) in Post Oak Savannah were not killed by 2.24 kg/ha. Karbutilate eliminated all vegetation in a 25 to 45-cm diameter circle, depending on concentration of active ingredient in the ball, the year of treatment regardless of vegetation region. The bare areas were revegetated within 2 yr following application in the Post Oak Savannah. However, bare areas in sodgrasses, primarily tobosa [Hilaria mutica (Buckl.) Benth.] and buffalograss [Buchloe dactyloides (Nutt.) Engelm.], where 1.12 and 2.24 kg/ha were applied averaged 20 to 30 in diameter, respectively, 32 months after application to sandy clay loam in the Rolling Plains.


Weed Science ◽  
1978 ◽  
Vol 26 (5) ◽  
pp. 444-453 ◽  
Author(s):  
R. E. Meyer ◽  
R. W. Bovey ◽  
J. R. Baur

Granule, and in some cases, tablet and ball formulations of bromacil (5-bromo-3-sec-butyl-6-methyluracil), dicamba (3,6-dichloro-o-anisic acid), picloram (4-amino-3,5,6-trichloropicolinic acid), karbutilate [tert-butylcarbamic acid ester with 3(m-hydroxyphenyl)-1,1-dimethylurea], and tebuthiuron {N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N′-dimethyl urea} were applied to three areas within 30 km of College Station in the Claypan Resource area of Texas. Woody species growing in the area included blackjack oak(Quercus marilandicaMuenchh.), post oak(Quercus stellataWangenh.), yaupon(Ilex vomitoriaAit.), winged elm(Ulmus alataMichx.), white ash(Fraxinus americanaL.), mockernut hickory(Carya tomentosaNutt.), and tree huckleberry(Vaccinium arboreumMarsh.). Granules were applied either broadcast or in rows at several intervals. Tebuthiuron was the most effective herbicide on oaks, winged elm, and white ash. Tebuthiuron and picloram were equally and most effective on yaupon, mockernut hickory, and tree huckleberry. Tebuthiuron + picloram at 2.2 + 2.2 kg/ha was the most effective herbicide treatment on huckleberry. However, a mixture of tebuthiuron + picloram (1:1 w/w) was usually no more effective than the same rate of tebuthiuron in the mixture applied alone. Tablet and ball formulations of karbutilate and tablet formulations of tebuthiuron were generally equally as effective as granules. Applications of picloram and tebuthiuron granules in rows 1.8, 3.0, 4.6, or 6.1 m apart gave control equal to broadcast applications except for picloram on yaupon. On yaupon all row spacing treatments of picloram were less effective than the broadcast treatment, whereas with tebuthiuron the 6.1-m spacing was least effective. Picloram and tebuthiuron granules applied in rows, approximately at 1.8-m intervals with a tractor, were as effective as granules applied by hand in straight rows.


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