A Systematic Map to Identify Knowledge Gaps on a Vector of Citrus Greening Diseases: The African Citrus Triozid, <i>Trioza erytreae</i> (Del Guercio, 1918) (Hemiptera: Triozidae)

Abstract

ABSTRACT Globally, citrus production areas are threatened by greening diseases, also known as Huánglóngbíng (HLB), associated with phloem‐limited gram‐negative species of the genus Candidatus Liberibacter. Those pathogens are transmitted by either the Asian citrus psyllid, Diaphorina citri Kuwayama 1908 (Hemiptera: Psyllidae), or the African citrus triozid, Trioza erytreae (Del Guercio, 1918) (Hemiptera: Triozidae). Asian citrus greening associated with ‘ Candidatus Liberibacter asiaticus’ (HLB‐CLas) is the most severe form of the disease and is primarily transmitted by D. citri , although T. erytreae can also acquire and transmit the pathogen. African citrus greening associated with ‘ Candidatus Liberibacter africanus’ (HLB‐CLaf), vectored by T. erytreae , caused major yield losses in South Africa during the 1970s. Diaphorina citri was detected in East Africa in 2015, while T. erytreae was reported in Southern Europe around the same time. Currently, the most effective way to limit citrus tree infection by HLB is to manage its vectors, which requires that their biology be understood. While there is extensive literature on D. citri , we show that T. erytreae is currently understudied. Using a systematic map approach, we reviewed the literature for T. erytreae and identified knowledge gaps for this species. Among the 86 articles identified, most were on distribution and monitoring (31.03%) and control methods (17.24%). Topics such as thermal biology, chemical ecology or host plants represent the largest knowledge gap, with each category representing &lt; 7% of the research literature.