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The Current Status and Control of Horseweed (Conyza canadensis) in Ohio Soybean (Glycine max) Production

Lamb, Alyssa
http://rave.ohiolink.edu/etdc/view?acc_num=osu1523877602007281

Abstract Details

2018, Master of Science, Ohio State University, Horticulture and Crop Science.
Studies were conducted from 2013 through 2017 with the objectives of: 1) optimizing a cereal rye cover crop program for the control of glyphosate-resistant (GR) horseweed in soybean production; and 2) determining the frequency, infestation level, and distribution of some of the most common and troublesome weeds in Ohio soybean fields as well as the spatial and temporal distribution of horseweed populations. Two studies were conducted simultaneously from fall of 2016 to fall of 2017 to evaluate how the planting date and seeding rate of a cereal rye cover crop affect horseweed population density, and the utility of cereal rye to aid or replace control from spring preplant residual (Study I) or fall herbicides (Study II). There was no difference in horseweed population density as a result of rye planting date in either study. The rye seeding rate affected horseweed density throughout the season in both studies. Horseweed density was greater in the absence of rye compared to either seeding rate. In Study I, the flumioxazin + metribuzin spring preplant residual reduced horseweed density in June compared with no or low level residual. In July, the flumioxazin + metribuzin treatments had a reduced horseweed density compared to the nontreated, but the flumioxazin alone was not different than the mixture or nontreated. In Study II, the fall herbicide treatment reduced horseweed density until July compared with the absence of a fall treatment. These results suggest that cereal rye used as a cover crop before no-till soybeans can reduce GR horseweed plant density, but that fall herbicide treatments and comprehensive spring residual programs are still important to ensure effective GR horseweed control into the growing season. A survey was conducted annually from 2013 through 2017 in 49 to 52 counties in Ohio soybean fields to assess the frequency, infestation level, and distribution of horseweed, giant ragweed (Ambrosia trifida), common ragweed (Ambrosia artemisiifolia), and three Amaranthus or `pigweed’ species. Horseweed was the most frequently encountered species in all years, followed by giant ragweed, pigweeds, and common ragweed, respectively. Horseweed also had the greatest number of infestations (highest density) each year, followed by giant ragweed, common ragweed, and pigweed species, respectively. Spatial cores of interest, or counties identified as having significant levels of horseweed infestations or lack thereof, relative to surrounding counties, were identified in 2013, 2014, 2015 and 2016, but not 2017. However, the lowest total frequency of horseweed occurred in 2017, which coincided with second highest frequency of infestations among years. There was no distinct distribution or pattern of horseweed movement within the state from year to year, but there did seem to be an increase in counties with one to three infested fields over time compared to the early years of the survey where many counties had one or no infested fields. These results suggest that horseweed persists as a common and troublesome threat to Ohio soybean producers, and that growers should still consider making horseweed management a priority when developing weed control programs.
Mark Loux (Advisor)
Alex Lindsey (Committee Member)
Emilie Regnier (Committee Member)
130 p.
Agriculture

Recommended Citations

Citations

  • Lamb, A. (2018). The Current Status and Control of Horseweed (Conyza canadensis) in Ohio Soybean (Glycine max) Production [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1523877602007281

    APA Style (7th edition)

  • Lamb, Alyssa. The Current Status and Control of Horseweed (Conyza canadensis) in Ohio Soybean (Glycine max) Production. 2018. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1523877602007281.

    MLA Style (8th edition)

  • Lamb, Alyssa. "The Current Status and Control of Horseweed (Conyza canadensis) in Ohio Soybean (Glycine max) Production." Master's thesis, Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1523877602007281

    Chicago Manual of Style (17th edition)

osu1523877602007281
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This open access ETD is published by The Ohio State University and OhioLINK.