Herbicide evaluation studies for the control of tarbush (<i>Flourensia cernua</i>)

TitleHerbicide evaluation studies for the control of tarbush (Flourensia cernua)
Publication TypeReport
Year of Publication1969
AuthorsGould W.L, Herbel C.H.
Series TitleResearch Progress Report, Western Society of Weed Science
Date Published1969
InstitutionResearch Progress Report, Western Society of Weed Science
Keywordscontrol, evaluation, Flourensia cernua, herbicide, tarbush

Tarbush is a deciduous desert species which is found in dense stands on silty or clay loam sites on flood plains. The date of leaf emergence is dependent upon adequate soil mosture, so in some droughty years it may not leaf out until the summer rains occur. The studies reported were carried out on the Jornada Experimental Range near las Cruces, New Mexico, from 1961 through 1965 to determine the best time for treatment and the best herbicides for selective control. Treatments were applied semi-monthly on 1/100 A plots using a simulated aerial application from July through October in 1961 and 1965. Treatments were initiated in August 1962, on May 7, 1963, and on June 3, 1964. Defoliation estimates were made approximately 2 years after treatments were applied. The 1961 treatments included 2,4-D, 2,4-DP, 2,4,5-T, silvex, 2,3,6-TBA and amitrole-T at 1/2 lb/A. Dicamba was added to the list of test materials in 1962 and picloram was added in 1963. Herbicides were applied on all spray dates at 1/2 lb/A in 1962, 1 lb/A in 1963 and 1 1/2 lb/A in 1964 and 1965. Additional treatments with higher rates of herbicides were applied on one spray date ind 1962, 1963 and 1964. The defgree of defoliation was quite variable between dates of application with the September treatments being most toxic generally. At rates up to 2 lb/A, the phenoxy herbicides and amitrole-T usually gave less than 30% defoliation. Dicamba was the most toxic material, causing 70% defoliation on one or more spray dates each year. Increasing the rate of dicamba from 1/2 to 2 lb/A increased the degree of defoliation only when treatment was not on the optimum date. At comparable rates, picloram and 2,3,6-TBA were much less effective than dicamba.