The utilization of cover crops and no-till practices are important for the conservation of both soil and moisture in South Dakota. However, it is unknown if these practices impact the efficacy of insecticide seed treatments. In soybean, insecticide seed treatments are used prophylactically to prevent potential crop losses from early season insect pests. The prophylactic use of any management strategy increases the likelihood for selection pressure and also represents unnecessary input costs. The purpose of the research conducted for Chapter 2 was to determine the impact that tillage systems, cover crops and planting populations have on the efficacy of insecticide seed treatments. Two years of field data was collected from established long-term tillage and cover crop rotation plots at the South Dakota State University Southeast Research Farm. During each year, four factors were evaluated for their impact on yield (i.e., tillage, cover crop, seeding rate and seed treatment). Stand counts, soil samples and yield data were taken from each plot. In Chapter 3, we evaluated pyrethroid resistance in soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae) populations in South Dakota. In 2015, the University of Minnesota discovered populations of the soybean aphid that were partially resistant to pyrethroid insecticides. Due to the soybean aphid’s capacity for rapid reproduction and its ability to travel long distances in its alate (i.e., winged) form, it was determined that South Dakota may have resistant populations present. In 2017 and 2018, an efficacy study was deployed at three locations, over two years throughout Eastern South Dakota. A total of eight foliar insecticides were used in 2017 and 10 foliar insecticides in 2018. The results from chapter 2 indicate that seed treatment and cover crops have no significant impact on soybean yield. The results from chapter 3 determined that pyrethroid resistant soybean aphids are present in South Dakota.
|Advisor:||Varenhorst, Adam J.|
|Commitee:||Fuller, Billy, Kleinjan, Jonathan|
|School:||South Dakota State University|
|School Location:||United States -- South Dakota|
|Source:||MAI 58/05M(E), Masters Abstracts International|
|Subjects:||Entomology, Plant sciences|
|Keywords:||Aphid resistance, Below ground insects, Insect feeding, Neonicotinoid, Pyrethroid reistance|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be