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ARS Home » Research » Publications at this Location » Publication #118689
Title: MESOTRIONE EFFICACY RESPONSE TO RAINFALL AND SOIL WATER

Author
item SIMMONS, F - UNIV OF ILLINOIS
item PARKER, DANIEL - UNIV OF ILLINOIS
item WAX, LOYD

Submitted to: North Central Weed Science Society US Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 1/8/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The effect of rainfall amount on efficacy of mesotrione on velvetleaf (Abutilon Theophrasti Medicus.) was compared with atrazine under a moveable rain exclusion shelter (RES) in 1999 and 2000. The RES contains 120 experimental units (4 x 4 feet) with irrigation controllable over six adjacent units. The soil type was a Drummer silty clay loam, OM = 5.0%. Factorial experiments including two rates of mesotrione, atrazine, acetochlor, and an untreated check were run three times in 1999, with six water amounts (0.0, 0.33, 0.64, 0.97, 1.27 and 1.90 cm). In 2000, the herbicide treatments included two rates of mesotrione, atrazine, an atrazine-mesotrione mix, isoxaflutole, and a check with he same rainfall amounts except for the 0.33-cm rate. Irrigation was added within 4-12 after herbicide application. Plant counts were made at time intervals beginning 2 weeks after experiment initiation. After the initial evaluation at 2 weeks, natural rainfall was allowed on the plots. Relative velvetleaf control by mesotrione within experiments was insensitive to rainfall rate between 0.64 and 1.90 cm. Initial soil water content at the time of experiment initiation affected the magnitude of velvetleaf control associated with different levels of additional rainfall. Velvetleaf control by atrazine and the mesotrione-atrazine mixture showed a linear increase with rainfall amount. Renewed herbicidal activity was observed on velvetleaf plants following rain occurring between 2 and 4 weeks after mesotrione soil applications.