The presence of Diaphorina citri (Asian citrus psyllid, or ACP), the primary vector of the dreaded Huanglongbing disease (HLB, or Asian Citrus Greening), was first reported in east Africa in Tanzania (2015) and Kenya (2016). Surveys that CRI conducted in collaboration with local scientists, confirmed the presence of ACP in the eastern regions of Tanzania. Recently HLB, previously known to occur in some parts of Ethiopia, was detected on the east coast of Kenya (Fig. 1). The recent detection of HLB in Kenya brings it considerably closer to citrus production in Southern Africa. CRI has engaged in a process with Department of Agriculture, Land Reform and Rural Development (DALRRD) to encourage Kenyan partners to scope the possibility of containing and eradicating the disease in the region.
A strong increase in global demand for citrus has so far been evident in the 2020 export season, according to Justin Chadwick, CEO of the Citrus Growers’ Association of Southern Africa.
In a statement, Chadwick said increased global demand for lemons had resulted in 4,5 million 15kg-equivalent cartons being shipped to date. This was double the 1,8 million cartons exported during the same period in 2019.
Assessment of unconventional antimicrobial compounds for the control of ‘Candidatus Liberibacter asiaticus’, the causative agent of citrus greening disease.
In this study, newly identified small molecules were examined for efficacy against ‘Candidatus Liberibacter asiaticus’ in commercial groves of sweet orange (Citrus sinensis) and white grapefruit (Citrus paradisi) trees. We used benzbromarone and/or tolfenamic acid delivered by trunk injection. We evaluated safety and efficacy parameters by performing RNAseq of the citrus host responses, 16S rRNA gene sequencing to characterize citrus-associated microbial communities during treatment, and qRT-PCR as an indirect determination of ‘Ca. L. asiaticus’ viability. Analyses of the C. sinensis transcriptome indicated that each treatment consistently induced genes associated with normal metabolism and growth, without compromising tree viability or negatively affecting the indigenous citrus-associated microbiota.