Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Byrd, John D., Jr

Committee Member

Chambers, Howard W.

Committee Member

Massey, Joseph H.

Committee Member

Madsen, John D.

Committee Member

Bryson, Charles T.

Date of Degree

12-15-2012

Document Type

Dissertation - Open Access

Major

Weed Science

Degree Name

Doctor of Philosophy

College

College of Agriculture and Life Sciences

Department

Department of Plant and Soil Sciences

Abstract

Herbicides were evaluated for control of non-native and invasive plants namely tropical soda apple (TSA) (Solanum viarum), tropical spiderwort or Benghal dayflower (Commelina benghalensis), and Italian ryegrass (Lolium multiflorum) from 2007 to 2012 in greenhouse at Plant Science Research Center, Mississippi State University, Starkville-Mississippi. In TSA study, aminopyralid at 0.88 or 0.12 kg ae/ha, and triclopyr + picloram + 2,4-D at (0.56 + 0.15 + 0.56) kg ae/ha controlled TSA seedlings emergence ranged from 83 to 96% at premergence (PRE), and 1 month after treatments (MAT). All herbicides failed to provide more than 63% control of TSA at 3 and 6 MAT. In Benghal dayflower study, bentazon, bromoxynil, chlorimuron ethyl plus tribenuron methyl, dimethenamid-P, nicosulfuron plus rimsulfuron, primisulfuron-methyl, S-metolachlor plus glyphosate plus mesotrione, and sulfosulfuron provided less than 50% control of Benghal dayflower during 6 weeks of evaluation whereas other herbicides: aminocyclopyrachlor (34-96%) ametryn (2-55%), atrazine (2-68%), diclosulam (12-67%), flumioxazin (59-83%), saflufenacil (24-78%), and sulfentrazone (67-96%) provided variable control of Benghal dayflower. In Italian ryegrass study, 50 seeds of F1 generation of resistant biotype ’49E’ and susceptible biotypes ‘Gulf’ and ‘Marshall’ of Italian ryegrass which were previously grown in mixture were used. Each biotype’s F1 generation responce to imazapyr at 0, 1, and 2% under PRE, early post emergence (EPOST) and late postemergence (LPOST) was evaluated. At PRE, imazapyr at 1 and 2% reduced ‘49E’ seedlings emerged 3 and 18%, respectively, but both rates failed to have any significant impact on fresh biomass weight compared to untreated. At EPOST, survival of ‘49E’ shoots were reduced 3 to 10% by both rate of imazapyr whereas only imazapyr at 1% caused 0.74 to 3.8 % fresh biomass reduction. At LPOST, ‘49E’ shoot survival was reduced 9 to 12% by both rate of imazapyr whereas both rate of imazapyr reduced ‘49E’ fresh biomass 3 to 31%. In all the PRE, EPOST, and LPOST experiments, ‘Gulf’ and ‘Marshall’ were still susceptible to the imazapyr.

URI

https://hdl.handle.net/11668/20396

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