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

Abstract

1 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 (CLas), which is the presumed causal agent of citrus greening disease. 2 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). 3 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. 4 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. 5 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.

Factors associated with Diaphorina citri immigration into commercial citrus orchards in São Paulo State, Brazil

“…In this period, 65% of the total psyllids were collected on sticky traps. Studies with small spatial time series (2 years and 2–3 sampling points), and with a resident population of psyllids (areas with poor or no control), showed that population peaks occur during spring and summer in SPS (Yamamoto et al., 2001) and Florida, USA (Hall et al., 2008; Lewis‐Rosenblum et al., 2015; Pelz‐Stelinski et al., 2016). The same was observed by Hernández‐Landa (2018) and Hall and Hentz (2011), who observed peaks of D. citri population occurring in the summer and spring, respectively.…”

Population Fluctuations of Diaphorina citri and Its Natural Enemies in Response to Various Management Practices in Florida

“…Populations of adult D. citri peaked during May, Jun, and Jul in conventional groves, while similar peaks were not observed in organic counterparts. Another factor explain-ing higher psyllid populations in intermittently sprayed than organic groves observed here might be that the level of insecticide input used was insufficient to adequately reduce D. citri populations as similarly observed in Pelz-Stelinski et al (2017), yet sufficient to disrupt normal activity of natural enemies. More D. citri found in intermittently managed conventional groves also could indicate some level of insecticide resistance among populations of D. citri in these groves.…”

“…The vector, D. citri, was identified in Florida in 1998 (Zhang et al 2014;Alvarez et al 2016). Recommended management practices for huanglongbing include use of disease free stock, inoculum removal by destruction of infected trees, and suppression of D. citri populations with insecticides (Brlansky et al 2009;Alvarez et al 2016;Pelz-Stelinski et al 2017). To date, there is no cure for the disease.…”

“…Although various vector control strategies have been explored in citrus groves, including cultural, chemical, and biological control, insecticide use has been the most prevalent method employed by growers given the rapid and visible effects on pest mortality (Qureshi & Stansly 2007;Boina & Bloomquist 2015). Although management practices for D. citri vary among Florida citrus growers (Pelz-Stelinski et al 2017), use of foliar and systemic insecticides is the most common tactic for reducing D. citri populations Boina & Bloomquist 2015). Until recently, growers following standard commercial management practices have made between 8 and 12 insecticide applications per yr, including neonicotinoids, organophosphates, and pyrethroids (Grafton-Cardwell et al 2013).…”

“…The sustainability of citrus production in Florida, where huanglongbing is well established, depends on effective management of D. citri. We hypothesized that the impact of natural enemies on populations of D. citri would be lower in citrus groves managed with intermittent application of conventional insecticides than in organic groves with no insecticide sprays, as suggested by Pelz-Stelinski et al (2017). The objective of this research was to compare the effects of intermittently applied conventional insecticides versus organic management practices on population suppression of D. citri by natural enemies under high huanglongbing incidence.…”