Dispersal Patterns of Diaphorina citri (Kuwayama) (Hemiptera: Liviidae) as Influenced by Citrus Grove Management and Abiotic Factors

Abstract

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), remains the most economically important and difficult to manage pest in citrus throughout Florida. To improve existing control methods, the potential for Asian citrus psyllid to evade insecticide sprays and engage in shortterm dispersal was investigated. Dispersal was evaluated to better understand responses of Asian citrus psyllid to citrus grove management, and how these factors affect population dynamics when citrus flush is scarce. To determine the impact of insecticide applications and other abiotic factors on Asian citrus psyllid movement, psyllid captures were measured on yellow sticky-card traps placed along the citrus grove borders. Additional suction trap and citrus grove stem-tap samples were collected and compared with sticky card catches, then correlated with data taken from the Florida Automated Weather Network. More Asian citrus psyllids were caught after than directly before insecticide sprays (t = 3.096; df = 27; P = 0.005), with the highest catches occurring from Mar to May. Both solar radiation and wind direction were positively correlated with Asian citrus psyllid dispersal, whereas humidity was negatively correlated across all sampling methods. Significant psyllid catches in suction traps located 500 m from a citrus grove provide additional evidence that Asian citrus psyllids tend to migrate when host conditions are unfavorable, returning to previous or neighboring groves after dispersal.