Author ORCID Identifier

https://orcid.org/0000-0003-2591-1196

Year of Publication

2020

Degree Name

Master of Science (MS)

Document Type

Master's Thesis

College

Agriculture, Food and Environment

Department

Entomology

First Advisor

Dr. Ricardo T. Bessin

Second Advisor

Dr. Raul T. Villanueva

Abstract

Phytophagous stink bugs (Hemiptera: Pentatomidae) are pests of significant importance to soybean, Glycine max (L.), because they can cause severe losses in seed quality, ultimately affecting yield. Damage to soybean is caused through a process called extra-oral digestion. This occurs when the adults and nymphs of stink bugs pierce plant tissues with their mandibular and maxillary stylets, insert digestive enzymes, break down tissue, and extract the digested plant fluid. Three endemic stink bug species of North America are present in Kentucky: green stink bug (Chinavia hilaris), brown stink bugs (Euschistus species complex), and red-shouldered stink bug (Thyanta custator). In addition, the invasive brown marmorated stink bug, Halyomorpha halys, has become a more serious soybean pest in the last two decades in certain regions of the country including Kentucky. Soybean is the most valuable commodity crop in Kentucky, bringing in over $700 million in revenue. Given that stink bugs can be detrimental to yield, understanding the effects that particular integrated pest management tactics have on stink bug densities is crucial. The objectives of this thesis are to 1) compare sampling methods used to assess stink bug population size and distribution, 2) evaluate the effects of stink bug populations between full and double-crop season soybean, and 3) compare control tactics for the management of stink bugs. These studies were conducted in several commercial fields located in western and central Kentucky counties and field plots at the UKREC in Princeton, KY. The results of these studies showed that: 1) beat-bucket sampling method produced similar density estimates of stink bugs compared with sweep net and may be a promising method to assess stink bug densities in the field as a replacement for the beat sheet technique, but an economic threshold needs to be established for this method; 2) stink bug species composition changed from western to central counties, where H. halys was the predominant species in the central region 3) seasonal stink bugs densities varied based on the physiological stage of soybean in both full and double-crop soybean in 2018; Similar trends in stink bug densities in 2019 full season soybean was documented, where densities in the field were based on food availability and developmental stage 4) the use of calendar sprays resulted in greater insecticide usage without gains in yield to justify their use when compared to a scout and spray if needed approach. Overall, proper pest management strategies should be incorporated to soybean production to assure sustainable suppression of stink bug insect pests.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2020.523

Funding Information

Kentucky Soybean Promotion Council from 2018 to 2020

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