PoPulation Dynamics of DIAPHORINA CITRI KuWayama (HemiPtera: liViiDae) in orcHarDs of ‘Valencia’ orange, ‘PonKan’ manDarin anD ‘murcott’ tangor trees

the purpose of this work was to study the population dynamics of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) in orchards of ‘Valencia’ orange, ‘Ponkan’ mandarin, and ‘murcott’ tangor trees located at the são José farm in the municipality of taquaritinga, são Paulo (sP). yellow sticky traps used to monitor this disease vector were evaluated monthly for 4 yr between sep 2004 and aug 2008. the largest number of D. citri was captured on the ‘Ponkan’ mandarin trees followed by the ‘murcott’ tangor and ‘Valencia’ orange trees with significant differences. chemical pest control and environmental factors likely are responsible for these results. Pearson’s correlation analysis indicated that there is a weak correlation between the abundance of D. citri and the environmental factors of temperature and precipitation. an analysis of variance suggested that there was a significant difference in the abundance of D. citri among the 3 citrus tree varieties, and the autocorrelation was significant for the ‘Valencia’ orange orchard. spectral analysis indicated that there were greater frequencies of peaks in the ‘Ponkan’ mandarin and ‘murcott’ tangor trees, and the simulations performed using a stochastic logistic model suggested that the psyllid populations on orange trees are the most susceptible to local extinction; this result likely occurred because of the high levels of chemical control applied to orange trees. therefore, in a D. citri management program, the different citrus varieties planted on a farm should be considered, thus varieties without the proper management of the vector does not become a source of psyllids for infestation of other varieties.