TY - JOUR T1 - Toxicity of Several Herbicides to Grape Rootings applied to the Roots and to the Shoots JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 206 LP - 213 DO - 10.5344/ajev.1964.15.4.206 VL - 15 IS - 4 AU - O. A. Leonard AU - L. A. Lider AU - A. H. Lange Y1 - 1964/01/01 UR - http://www.ajevonline.org/content/15/4/206.abstract N2 - Fifteen herbicides were applied to Thompson Seedless grape rootings to note the development of symptoms and to determine relative toxicity of the various chemicals (from root or shoot application).Dalapon, paraquat, and DCPA at 5 ppm were the least toxic of the herbicides applied to the roots. Trifluralin at this concentration produced no foliage symptoms although some weight reduction occurred. Amitrole was only slightly injurious at 5 ppm concentration but was moderately toxic at 50 ppm. The three triazines, prometryne, atrazine, and simazine, were fairly similar in toxicity, with all rootings dying at the 5-ppm concentration; prometryne, however, appeared to be slightly less toxic than the other two triazines. Dichlorobenil killed the rootings at 5 ppm and resulted in considerable root shortening at 0.5 ppm. Diuron and isocil were more toxic than the triazines, since the rootings all died with 0.5 ppm treatments. The growth regulators, 2,4-D, dicamba, and Tordon varied considerably in toxicity, with 2,4-D least toxic and Tordon most toxic. The presence of strong formative effects on the shoots with dicamba and Tordon indicated that these herbicides were translocated from the roots to the shoots; the absence of such effects with 2,4-D indicated that no such movement occurred with this compound.Paraquat and dalapon were lethal to grape rootings at 500 ppm; limited toxicity was indicated when 50 ppm were used.When these herbicides were applied to the shoots, the toxicities were frequently quite different from that encountered with root treatment. Dichlorobenil, DCPA, and trifluralin were not toxic. Dalapon at 10 pounds per acre reduced rooting growth only moderately. EPTC of 10 pounds per acre produced slight chlorosis but no reduction in plant weight. Simazine of 10 pounds per acre resulted in some leaf injury, and at 1 pound per acre produced a slight leaf chlorosis on some plants. Atrazine and prometryne were appreciably more toxic to the grape rootings than was simazine; diuron was next in order of toxicity, and isocil the most toxic. Amitrole reduced growth appreciably at 10 pounds per acre, but had only slight effects at 1 pound per acre.The growth regulators 2,4-D, dicamba, and Tordon were somewhat similar in toxicity when applied to the foliage. 2,4-D killed the plants most rapidly, but Tordon was toxic at a lower concentration than was either 2,4-D or dicamba.An ester and an amine form of 2,4-D was applied to the foliage of rootings. It was observed that 0.002 pound of 2,4-D per acre resulted in no definite symptoms, although the leaf margins were temporarily rolled; there was no evident difference in the toxicities of the two forms of 2,4-D. A dose at 0.02 pound at 2,4-D per acre resulted in marked formative effects, which disappeared by 40 days following application. Greater doses killed the rootings. ER -