Date of Graduation

12-2022

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Entomology (PhD)

Degree Level

Graduate

Department

Entomology and Plant Pathology

Advisor/Mentor

Bateman, Nicholas R.

Committee Member

Thrash, Benjamin C.

Second Committee Member

Lorenz, Gustav M. III

Third Committee Member

Hardke, Jarrod T.

Fourth Committee Member

Joshi, Neelendra K.

Keywords

Furrow-irrigated rice; Integrated pest management; Rice billbug; Sphenophorus pertinax

Abstract

Furrow-irrigated rice hectares have increased annually for the last five years in the predominant long-grain rice producing states. Initial implementation of the system began in the 1980’s, but lack of rice blast (Magnaporthe grisea, Hebert) resistant cultivars made the system a nonviable option for rice producers. Hybridization of rice cultivars with less susceptibility has begun to increase the interest of producers to implement a furrow-irrigated rice production system due to the cost saving opportunities that it may provide. Elimination of the flood from large sections of the rice fields in a furrow-irrigated system alters management strategies and pest complexes compared to the traditional flooded system. Large portions of these production fields remaining nonaquatic, increasing the susceptibility to previously uncommon pests of flooded rice. Considered a minor pest in traditional flooded systems, rice billbug (Sphenophorus pertinax, Chittenden) could become the most detrimental insect of furrow-irrigated rice. Rice billbug feed on the roots and tillers of the rice plants, causing dead tillers and rice panicles to abort, resulting in indirect yield loss. As the system gains popularity and as hectares increases, questions on management strategies for control of rice billbug has become an issue for producers. Management plans for rice billbug have become a priority in the Mid-Southern rice producing states. The objectives of this research were to further expand knowledge and understanding of the biology of the rice billbug, developing monitoring regimes, and control strategies to suppress rice billbug. Multiple experiments were conducted from 2019-2022 across the Mid-Southern U.S. to increase knowledge of rice billbug biology and to develop recommendations for control of rice billbug. Surveys, trapping methods, insecticide efficacy, and insecticide application methods were evaluated to create a full management strategy for rice billbug. Volatile semiochemical extraction was also conducted in the lab to determine the potential for pheromone development for monitoring and control. Findings in these studies suggest that rice billbug are present across major rice growing states of the southern U.S., and monitoring systems designed for ground active insects can play a role in management and monitoring. These data also suggest the implementation of insecticide seed treatments containing a neonicotinoid in conjunction with a diamide is the most effective strategy for controlling rice billbug. Finally, findings from these studies suggest that there was a semiochemical response observed in rice billbug, but further development is warranted before mass adoption. These data have created a foundation for further studies by researchers across the rice producing states of the United States.

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