Field efficacy and availability, movement, and persistence of ICIA-0051 herbicide in soils

Fields studies conducted in 1987 and 1988 determined the weed control efficacy of ICIA-0051 and SC-0774 in conventional and no-till systems of corn (<i>Zea mays</i> L.) culture. Results of the preemergence and postemergence applications of ICIA-0051, across all treatments after 8 weeks, showed 85% control or better of triazine-resistant smooth pigweed (<i>Amaranthus hybridus</i> L.), while fall panicum (<i>Panicum dichotomiflorum</i> Michx.) control ranged from 43 to 87%. Giant ragweed (<i>Ambrosia trifida</i> L.) control ranged from 30 to 95%, while control of ivyleaf morningglory (<i>Ipomoea hederacea</i> (L.) Jacq.) was below 75% in the preemergence treatments and ranged from 89 to 99% in the postemergence treatments. In general, the addition of atrazine to the pre- and postemergence treatments of ICIA-0051 improved weed control. SC-0774 treatments gave 85% or better control of fall panicum, but inadequate broadleaf weed control (75% or worse). Soil mobility studies using soil thin-layer chromatography and soil leaching columns indicated that the movement of ICIA-0051 was highly negatively correlated with the organic/humic matter fraction. Although the mobility patterns were similar, ICIA-0051 was more mobile than SC-0774, which was more mobile than atrazine. A comparison of ICIA-0051 across soils indicated that the order of mobility was Appling loamy sand (Rf = 6.4) > Davidson clay (Rf = 5.6) > Bojac sandy loam (Rf = 5.0) = Frederick silt loam (Rf = 4.9) > Hyde silty clay loam (Rf = 1.1). Other soil properties such as the clay content and pH were not strongly correlated with ICIA-0051 movement. Results of the adsorption/desorption studies indicated that the organic/humic matter fraction was primarily responsible for the binding and retention of ICIA-0051 across the five soils investigated. Based on the K constants derived from the Freundlich equation, the order of adsorption was Hyde > Frederick > Davidson = Bojac > Appling. The desorption results indicated that ICIA-005l was not tightly bound to the soil particles, with losses between 20 and 50% of the amount adsorbed after two desorptions. Results of the greenhouse persistence study, using mustard (<i>Brassica kaber</i> L.) as a bioassay species, indicated that ICIA-0051 was more biologically available than atrazine. Similar to the adsorption and leaching results, the persistence of ICIA-0051 was highly positively correlated with the soils’ organic matter. Regardless of the rate used, crop injury decreased over time, although the highest rate (1 ppm of ICIA-0051) showed significant crop injury even after 6 months in several soils in the greenhouse studies.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Plant Physiology and Weed Science

Department dc:contributor.department

Plant Physiology and Weed Science

Grantor dc:publisher

Virginia Polytechnic Institute and State University

Year dc:date.issued

1989

Author dc:creator

• Wilson, John Samuel

Chair dc:contributor.committeechair

• Foy, Chester L.

Committee members dc:contributor.committeemember

• Baker, James C.
• Derr, Jeffrey F.
• Hagood, Edward S.
• Young, Roderick W.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/10919/54812

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/54812