Doctor of Philosophy (PhD)



Document Type



Sweetpotato weevil (SPW), Cylas formicarius elegantulus (Summer), is the most damaging root-feeding insect of sweetpotato, Ipomoea batatas L. (Lam), worldwide. The efficacy and compatibility of host plant resistance and insecticide control were evaluated in this dissertation. cv. Beauregard is the most susceptible cultivar for oviposition and offspring performance of SPW compared to cvs. Evangeline and Murasaki. The oviposition preference was shaped by the larval experience of SPW, providing evidence in support of the Hopkins’ Host-Plant Selection Principle. Although oviposition on cv. Murasaki was reduced, the egg capacity of SPW developed on cv. Murasaki was not decreased, indicating an adaptive behavior of egg-resorption to compensate encountering an inferior host. The larval performance was not influenced by the previous experience nor related to oviposition preference. Our study highlighted the importance of considering previous experience in host plant resistance studies. It is the first time such studies were conducted on SPW. Induced host plant resistance was found in SPW-infested plant against above-ground virus vectors, green peach aphid (GPA), Myzus persicae (Sulzer) and cotton aphid (CA), Aphis gossypii Glover. SPW infestation decreased the fitness and inhibited the feeding activities of above-ground virus vectors. When SPW population are controlled in the field, the virus epidemiology may be altered. Insecticide resistance was not detected in field-collected populations in Louisiana. Sweetpotato cultivars did not reduce insecticide efficacy against SPW, indicating compatibility of host plant resistance and insecticide control.



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Committee Chair

Davis, Jeffrey



Included in

Entomology Commons