Formulation and Adjuvant Effects on Uptake and Translocation of Clethodim in Bermudagrass (Cynodon dactylon)

• Published in: Weed science 2007-01, Vol.55 (1), p.6-11
• Main Authors: Nandula, Vijay K, Poston, Daniel H, Reddy, Krishna N, Koger, Clifford H
• Format: Article
• Language: English
• Subjects: Absorption; adjuvant; autoradiography; Biological and medical sciences; Chemical control; Crops; Cynodon dactylon; distribution; Fundamental and applied biological sciences. Psychology; grasses; greenhouse experimentation; Harvesting seasons; herbicide resistance; Herbicides; Natural light; Parasitic plants. Weeds; pesticide adjuvants; pesticide formulations; Photoperiod; PHYSIOLOGY, CHEMISTRY, AND BIOCHEMISTRY; Phytopathology. Animal pests. Plant and forest protection; Plants; Quaternary ammonium compounds; Sulfates; translocation (plant physiology); uptake mechanisms; Volunteerism; Weed science; Weeds
• ISSN: 0043-1745; 1550-2759
• DOI: 10.1614/WS-06-024.1

The effect of formulation and adjuvants on absorption and translocation of 14C-clethodim was determined at 1, 4, 12, 24, 48, and 72 h after treatment (HAT) in bermudagrass under greenhouse conditions. Absorption of 14C-clethodim with the 0.12 kg L−1 (15 to 85%) formulation was higher than with the 0.24 kg L−1 (5 to 40%) formulation, regardless of presence or absence of adjuvant. There was considerable variation in the effect of adjuvant on 14C-clethodim absorption. When either ammonium sulfate (AMS) or AMS plus crop oil concentrate (COC) was added to the 0.12 kg L−1 formulation, 14C-clethodim absorption increased significantly at all harvest times except at 12 HAT compared with 0.12 kg L−1 formulation alone, whereas, 14C-clethodim absorption after addition of COC to the 0.12 kg L−1 formulation was similar to the 0.12 kg L−1 formulation alone up to 24 HAT. Conversely, COC enhanced 14C-absorption at all harvest times when added to 0.24 kg L−1 formulation. Most of 14C-clethodim (79 to 100% of absorbed) remained in the treated leaf, independent of formulation or adjuvant. Formulation did not have an impact on distribution of absorbed 14C-clethodim; however, presence of an adjuvant increased movement of 14C-clethodim out of treated leaf. Of the absorbed 14C-label, most remained in the treated leaf. 14C-clethodim that translocated out of the treated leaf remained in the shoot, and negligible amount of 14C-clethodim translocated to roots. These results demonstrated improved absorption of clethodim with formulations containing half the active ingredient (0.12 kg L−1) and inclusion of both AMS and COC. Nomenclature: Clethodim; bermudagrass, Cynodon dactylon (L.) Pers. CYNDA.