Interactions of post emergence herbicides, strobilurin fungicides and Rhizoctonia root rot of soybean

Rhizoctonia root rot, caused by Rhizoctonia solani, is a major disease of soybeans in the north-central United States. The emergence of glyphosate resistant weeds and the payment premium for growing non-GMO soybeans has increased the use of non-glyphosate herbicides. However, some of these herbicides may increase the severity of root rot caused by Rhizoctonia solani Field and greenhouse studies were conducted to evaluate the potential interaction among glyphosate-tolerant soybeans, post emergence herbicides (glyphosate, acifluorfen, lactofen, imazethapyr), and fungicide seed treatments (azoxystrobin, pyraclostrobin, trifloxystrobin). Inoculum of R. solani (AG 2-2) was planted along with treated seed. Herbicides were applied at recommended field rates at the V4 growth stage. Plant stand was rated after seedling emergence, and soybean roots samples were collected two weeks after herbicide application. Based on the data of field study from two locations (Champaign, IL and Monmouth, IL) and the data from greenhouse trials, plant stand was found to be significantly increased in the fungicide treated plots compare to non-treated plots, and analysis of variance revealed a significant treatment effect on root rot severity. Lactofen treated plants showed the highest disease severity levels and reduced yields. The azoxystrobin seed treatment provided the best protection against Rhizoctonia root rot. There was no significant difference of root rot severity between glyphosate treated and non-treated plants.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Crop Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2012

Author dc:creator

• Zhang, Ren

Contributors dc:contributor

• Eastburn, Darin M.

• Rhizoctonia Root Rot
• Herbicide
• Fungicide
• Glyphosate

Statement dc:rights

• Copyright 2011 Ren Zhang

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/29445

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/29445