Influence of Abiotic Factors on Flight Initiation by Asian Citrus Psyllid (Hemiptera: Liviidae)

Predicting the emergence and arrival of insect pests is paramount for integrated pest management. To achieve this goal, it is important to understand how abiotic factors influence pest dispersal behavior. We investigated the effects of abiotic conditions on flight initiation by the Asian citrus psyllid, Diaphorina citri Kuwayama. We first explored the effect of barometric pressure changes on flight initiation. We used a custom-made barometric chamber and observed the activity of D. citri as measured by the number of psyllids captured on yellow cardboard panels coated with adhesive. We found that psyllid flight initiation changed in response to variations in barometric pressure rather than to differences in stable pressures. Diaphorina citri were equally active at 1,009 mbar and 1,022 mbar. However, D. citri dispersed more as barometric pressure increased, and less when barometric pressure decreased. In a subsequent experiment, we manipulated temperature and relative humidity and observed how D. citri dispersed between citrus plants. Psyllids dispersal increased linearly with temperature. Changes in humidity did not affect dispersal of D. citri. Less than 1% of psyllids dispersed at 15 °C, compared with 7.7% at 21 °C and 27% at 25 °C. The minimal threshold for D. citri to initiate flight is estimated to be 16.5 °C. Collectively, our results provide an initial step toward developing predictive models of D. citri movement as influenced by abiotic factors.