Detection and monitoring of 'Candidatus' Liberibacter spp. vectors: African citrus triozidTrioza erytreaeDel Guercio (Hemiptera: Triozidae) and Asian citrus psyllidDiaphorina citriKuwayama (Hemiptera: Liviidae) in citrus groves in East Africa

摘要

The African citrus triozid (ACT)Trioza erytreae(Del Guercio) (Hemiptera: Triozidae) and the Asian citrus psyllid (ACP)Diaphorina citri(Kuwayama) (Hemiptera: Liviidae) are primary vectors of the 'Candidatus' Liberibacter spp. ACT is associated with 'CandidatusLiberibacter africanus' (CLaf) causal agent of the African citrus greening disease (ACGD), whereas ACP vectors 'CandidatusLiberibacter asiaticus' (CLas) and 'CandidatusLiberibacter americanus' (CLam), the Asian and the American strains, respectively, associated with huanglongbing. A preliminary survey in Kenyan citrus groves after the invasion of ACP had revealed that lime-green sticky traps (Asacp) were not effective in detecting and monitoring ACT and ACP. Therefore, this study compared eight differently coloured double-sided sticky traps to evaluate, which colour was most effective for detecting ACT and ACP, particularly at low densities. The traps were coded Red, Blue, Asgreen1, GLMgreen, Asacp, Asyellow, White, and Black. Asyellow and GLMgreen traps captured more ACTs and ACPs than any other trap type. However, since there was no clear difference in the efficiency of Asyellow and GLMgreen in trapping ACP, any of the two trap types would be useful in the presence of both pests. Among the eight traps, Asyellow and GLMgreen traps are potentially promising options for monitoring and detecting the pests in areas where they coexist. Our findings will guide biosecurity agencies in decision-making and designing ecologically friendly integrated pest management (IPM) strategies for citrus greening vectors in Africa as well as serve as an early warning to safeguard against pests' invasion into unaffected areas.