Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


Master Thesis_SN.pdf (1.7 MB)

ETD Abstract Container

Abstract Header

The Effect of Mid-season Foliar Fungicide and Insecticide, Applied Alone or in Combination, on Soybean Yield in Ohio

Ng, Sin Joe
http://rave.ohiolink.edu/etdc/view?acc_num=osu1491986629962156

Abstract Details

2017, Master of Science, Ohio State University, Horticulture and Crop Science.
Ohio soybean farmers are very concerned about disease and insect pressure during the midseason that may impact yield. The impact of mid-season management for foliar diseases and insect feeding on grain yield was studied in a series of field experiments. The first objective was to evaluate the effect of mid-season foliar fungicide and insecticide application on soybean yield, applied alone or in combination. A trial was established at 12 on-farm field site-years in Ohio during 2015 and 2016 in a randomized complete block design with four replications per treatment. Fungicide and insecticide treatments included: 1) nontreated control, 2) fungicide alone, 3) insecticide alone, 4) fungicide plus insecticide (tank-mixed), 5) fungicide and insecticide (separate tank), 6) fungicide plus crop oil, 7) insecticide plus crop oil, 8) fungicide, insecticide plus crop oil (tank-mixed). All treatments were applied at R3 growth stage (initial pod development), and data on the percent leaf area affected by foliar diseases and insect defoliation was collected. There was no significant yield response associated with insecticide application due to low insect pressure and low insect defoliation levels at the time of insecticide application at all 12 site-years. However, at the end of the growing season, the number of bean leaf beetles (2-22) and pod injury caused by their feeding (4.1-37%) were high at 4 out of 12 site-years. Fungicide application alone had significantly (P<0.05) higher yield of 4 to 8 bushel/acre at 4 of 12 site-years due to the high leaf area affected in the canopy from Septoria glycines and Cercospora sojina which cause brown spot and frogeye leaf spot disease, respectively. The mean yield from plots treated with a tank-mixture of fungicide and insecticide was not significant difference from those treated with the fungicide alone. In this study, insecticide applications were applied too early in the growing season to have an impact on late-season pod feeding. Based on the amount of pod feeding, a late-season insecticide application may have resulted in yield increase. Therefore, crop scouting throughout the growing season is especially necessary to determine disease and insect pressure level and to justify a fungicide or insecticide application. The second study examines the frogeye leaf spot incidence and soybean grain yields in Ohio using predictive models. Frogeye leaf spot of soybean, caused by the fungus Cercospora sojina, has become an increasing concern in Ohio soybean production due to the widespread planting of cultivars with moderate susceptibility. Frogeye leaf spot tends to appear late in the growing season (R4 to R5) and specific action thresholds have not been identified. The objective of this study was to develop a model that could be used to predict potential frogeye leaf spot disease severity and soybean grain yield, which would help growers in making disease management decisions. Data were collected from 28 site-years from 2013 to 2016, where variables such as treatment, location, tillage, rainfall, and winter temperature were included. Analysis of variance, analysis of covariance, and forward selection using regression analysis were used to create the models. After examining the models using R2, adjusted R2, and root mean square error, when yield was set as the dependent variable, equation: Yield = 63.4 + 2.8fungicide – 6.3central region – 7.8north region + 3.4tillage + 0.1rain – 0.1winter temperature (adjusted R2 = 0.15) was selected as the best model, and when disease incidence was set as the dependent variable, equation: FLS% = - 3.4 – 0.9fungicide + 0.8tillage + 0.1rain + 0.1winter temperature (adjusted R2 = 0.25) was selected the best model for soybean grower to use as decision making tool. Although based on the outcomes of this collection of fields where frogeye leaf spot disease was present and absent, there is still great uncertainty. These models can be used as the basis for future studies that incorporates more data to refine the models to predict soybean grain yield and late-season disease severity.
Laura Lindsey (Advisor)
Anne Dorrance (Committee Member)
Andrew Michel (Committee Member)
126 p.
Agriculture; Agronomy; Entomology; Plant Pathology; Plant Sciences
soybean; fungicide; insecticide; soybean disease; soybean insect pest; frogeye leaf spot; brown spot; bean leaf beetle; model; yield; agronomy; Ohio agriculture

Recommended Citations

Citations

  • Ng, S. J. (2017). The Effect of Mid-season Foliar Fungicide and Insecticide, Applied Alone or in Combination, on Soybean Yield in Ohio [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1491986629962156

    APA Style (7th edition)

  • Ng, Sin Joe. The Effect of Mid-season Foliar Fungicide and Insecticide, Applied Alone or in Combination, on Soybean Yield in Ohio. 2017. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1491986629962156.

    MLA Style (8th edition)

  • Ng, Sin Joe. "The Effect of Mid-season Foliar Fungicide and Insecticide, Applied Alone or in Combination, on Soybean Yield in Ohio." Master's thesis, Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1491986629962156

    Chicago Manual of Style (17th edition)

osu1491986629962156
359
© 2017, some rights reserved.Creative Commons License The Effect of Mid-season Foliar Fungicide and Insecticide, Applied Alone or in Combination, on Soybean Yield in Ohio by Sin Joe Ng is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by The Ohio State University and OhioLINK.