Asian citrus psyllid (Diaphorina citri) tolerance to heat

Authors: Hall, David; Hentz, Matthew

Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/7/2014
Publication Date: 4/30/2014
Citation: Hall, D.G., Hentz, M.G. 2014. Asian citrus psyllid (Diaphorina citri) tolerance to heat. Annals of the Entomological Society of America. 107:641-649.

Interpretive Summary: The Asian citrus psyllid (ACP) is an important citrus pest because it vectors bacteria responsible for a serious disease of citrus known as huanglongbing (also called citrus greening disease). ACP is known to favor warmer climates and in fact inhabits some of the hottest areas where citrus is grown. However, little was known regarding ACP tolerance to extreme heat. Laboratory experiments showed that adult ACP cannot survive 50°C for more than about 10 minutes and that death occurred faster at higher temperatures; males tended to be more heat tolerant than females; young adults were less tolerant of high temperatures than older adults; adult ACP predisposed to warmer temperatures were more heat tolerant than those predisposed to cooler temperatures; and heat treatments lethal to adult ACP were usually lethal to eggs and nymphs. A number of heat treatments lethal to ACP in an oven situation can be identified from the results of this research and would be useful to regulatory agencies interested in heat treatments to eliminate ACP.

Technical Abstract: The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, is an important citrus pest because it vectors bacteria responsible for a serious disease of citrus known as huanglongbing (also called citrus greening disease). ACP is known to favor warmer climates and in fact inhabits some of the hottest areas where citrus is grown. However, little was known regarding ACP tolerance to extreme heat. Working with an ACP colony maintained at 27°C, we assessed the survival of adult ACP exposed to temperatures of up to 60°C for various durations in a laboratory oven under ambient humidity levels, generally 21 to 23% regardless of the temperature. We found under our experimental conditions that adult ACP cannot survive 50°C for more than about 10 minutes and that death occurred faster at higher temperatures; males tended to be more heat tolerant than females; young adults were less tolerant of high temperatures than older adults; adult ACP predisposed to warmer temperatures were more heat tolerant than those predisposed to cooler temperatures; and heat treatments lethal to adult ACP were usually lethal to eggs and nymphs. We also found that ACP were less tolerant of heat treatments in the oven when the humidity level was high than when it was low. A number of heat treatments lethal to ACP in an oven situation can be identified from the results of this research and would be useful to regulatory agencies interested in heat treatments to eliminate ACP. To what extent the results of the research apply to ACP populations in the field remains to be investigated. It is likely that some heat treatments identified as lethal to ACP in an oven setting would not be lethal to ACP in a field setting as a result of evaporative cooling by the host plant.