Effect of nitrogen fertilization dose on Diaphorina citri (Hemiptera: Liviidae)

Authors: PHILLIPS, ELEANOR - University Of Florida; MELLIES, ANDREW - University Of Florida; ZESUTKO, EDWARD - University Of Florida; WEEKS, EMMA - University Of Florida; Allan, Sandra - Sandy

Submitted to: Journal of Agricultural and Urban Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/21/2023
Publication Date: 6/9/2023
Citation: Phillips, E.F., Mellies, A.J., Zesutko, E.J., Weeks, E.N., Allan, S.A. 2023. Effect of nitrogen fertilization dose on Diaphorina citri (Hemiptera: Liviidae). Journal of Agricultural and Urban Entomology. 39(1):29-47. https://doi.org/10.3954/JAUE22-18.
DOI: https://doi.org/10.3954/JAUE22-18

Interpretive Summary: Control of the Asian citrus psyllid, the vector of the pathogen that causes Huanglongbing or citrus greening, is critically important in terms of management of this devastating disease of citrus. Management decisions to protect citrus orchards are based on estimates of the psyllid populations infesting the orchards. Therefore, having an understanding nutritional factors that contribute to population increases of psyllids is critical. In this laboratory study, researchers at USDA-ARS, Center for Medical, Agricultural and Veterinary Entomology, Gainesville, Florida in collaboration with scientists at University of Florida, examined the impact of nitrogen fertilization of young citrus seedlings on increases in psyllid populations. The study found that moderate levels of nitrogen fertilization led to optimal growth of psyllid populations although excess levels reduced psyllid survival. This finding suggests that higher plant nitrogen levels restrict psyllid growth. Gaining insight into how nitrogen or other fertilizers impact growth of Asian citrus psyllid populations is necessary to determine the timing and duration of insecticide use and should contribute to development of improved integrated management strategies.

Technical Abstract: The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae) is a vector of the bacterium that causes Huanglongbing which is responsible for substantial loss of productivity in the Florida citrus industry. In this study, the effect of different levels of nitrogen fertilizer applied to Citrus sinensis seedlings were evaluated on various biological parameters of the Asian citrus psyllid. Nitrogen application levels compared were 0%, 50%, 100% and 200% of the recommended nitrogen levels for seedlings. Levels of micronutrients, potassium and phosphate were held constant throughout the experiment. Females produced more eggs from the 50% treatment compared to the 200% treatment and there was no difference between the 0%, 50% and 100% nitrogen treatments. There was no difference in development time of immatures from egg to adult eclosion between treatments. Reduced survival was observed only with the 200% nitrogen treatment. Morphometric analysis of wing features revealed greatest length with the 100% nitrogen treatment and 0% the shortest. Shape of wings differed significantly with the 200% nitrogen treatment distinct from all other treatments, and the 50% treatment different from the 100%. Application of the 200% nitrogen treatment had a negative impact on the psyllids likely due to detrimental effect of excess nitrogen on the plants. Chlorophyll content of new flush leaves did not differ between treatments before nitrogen treatment but at the end of the study, plants receiving 50% nitrogen levels were significantly greater in chlorophyll content than other treatments. Insight into how nitrogen fertilizer affects Asian citrus psyllid populations and thus the need for insecticide use may contribute to development of improved integrated management strategies.