Soil-applied herbicides were evaluated for control of blackjack oak (Quercus marilandica Muenchh.), huisache [Acacia farnesiana (L.) Willd.], honey mesquite [Prosopis juliflora (Swartz) DC. var. glandulosa (Torr.) Cockerell], live oak (Quercus virginiana Mill.), Macartney rose (Rosa bracteata Wendl.), winged elm (Ulmus alata Michx.), and yaupon (Ilex vomitoria Ait.) 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.

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 virginiana Mill. ♯4 QUEVI), post oak (Q. stellata Wangenh. ♯ QUESL), parsley hawthorn (Crataegus marshallii Egglest. ♯ CSCMS), and yaupon (Ilex vomitoria Ait. ♯ 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. marilandica Muechh.), yaupon, winged elm (Ulmus alata Michx. ♯ ULMAL), and mockernut hickory (Carya tomentosa Nutt.) regardless of date treated. Tree huckleberry (Vaccinium arboreum Marsh.) 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.

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 stellata Wangenh.), blackjack oak (Q. marilandica Muenchh.), water oak (Q. nigra L.), yaupon (Ilex vomitoria Ait.), winged elm (Ulmus alata Michx.), downy hawthorn (Crataegus mollis Scheele), gum bumelia [Bumelia lanuginosa (Michx.) Pers.], and willow baccharis (Baccharis salicina Torr. & Gray) in the Post Oak Savannah of Texas. Tree huckleberry (Vaccinium arboreum Marsh.), black hickory (Carya texana Buckl.), honeylocust (Gleditsia triachanthos L.) and cedar elm (Ulmus crassifolia Nutt.) were partially controlled by 2.2 kg/ha of tebuthiuron. Canopies of buckbrush (Symphoricarpos orbiculatus Moench), southern dewberry (Rubus trivialis Michx.), American beautyberry (Callicarpa americana L.), and persimmon (Diospyros virginiana L.) 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 virginiana L.), and Texas persimmon (Diospyros texana Scheele) were not controlled by tebuthiuron at 2.2 or 4.4 kg/ha, and saw greenbrier (Similax bona-nox L.) and peppervine [Ampelopsis arborea (L.) Koehne] apparently increased following application of tebuthiuron.