Effect of Nitrogen Fertilization Dose on Diaphorina citri (Hemiptera: Liviidae)

Abstract

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is a vector of the bacterium causing Huanglongbing and responsible for substantial productivity loss in the Florida citrus industry. In this study, the effect of different concentrations of nitrogen fertilizer applied to orange, Citrus × sinensis (L.) Osbeck (Rutaceae), seedlings on biological parameters of the Asian citrus psyllid was evaluated. Nitrogen was applied at 0, 7.5, 15 and 30 mg/L which represented 0%, 50%, 100%, and 200% of the recommended levels for seedlings, while holding the doses of micronutrients, potassium, and phosphate constant. Females produced 138% more eggs from the 50% treatment compared to the 200% treatment and there was no difference between the 0%, 50%, and 100% nitrogen treatments. Nymphal development time did not differ among nitrogen doses. Nymphal survival was reduced dramatically at 200% nitrogen treatment. Morphometric analysis revealed that female wings were longest with the 100% nitrogen treatment and shortest with 0%. Shape of wings differed significantly with the 200% nitrogen treatment distinct from all other treatments, and the 50% treatment differed from the 100%. Application of the 200% nitrogen treatment negatively impacted psyllids likely due to the detrimental effect of excess nitrogen on the plants. Chlorophyll content of newly flushed leaves did not differ among treatments before nitrogen treatment, but chlorophyll content in plants receiving 50% nitrogen levels was significantly greater than other treatments at the end of the study.