Patterns of habitat use by the Asian citrus psyllid, Diaphorina citri , as influenced by abiotic and biotic growing conditions

The Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Liviidae) is an economically important pest of citrus throughout Asia and the Americas because it transmits Candidatus Liberibacter asiaticus ( C Las), which is the presumed causal agent of citrus greening disease. We investigated whether biotic and abiotic characteristics can be used to predict Diaphorina citri population abundance and assessed whether agricultural intensity explained the distribution of D. citri populations during winter dormant periods (December to March). Over two consecutive winters, we examined the abundance of D. citri in groves throughout Florida in response to four different management regimes, defined as: conventional, intermittent, unmanaged and organic. During both years, the winter abundance of D. citri in groves with intermittent management was greater than in groves with other management regimes. Latitude and row orientation both had a significant effect on psyllid density during winter. Diaphorina citri abundance was higher when more than 20% of the surrounding landscape was urbanized. These findings suggest that only conventional management of groves reduced D. citri populations during winter periods. By contrast, intermittent management was associated with higher D. citri populations. These results might be of some concern in light of the economic and environmental costs of repeated insecticide applications and the dramatic decline of citrus production in the U.S.A.