Abstract
The Polyphagous shot hole borer (PSHB) ( Euwallacea fornicatus ) is attacking native and exotic street trees in Johannesburg’s urban forest causing a disease called Fusarium dieback (FD), and the date of introduction of PSHB is not known. The novelty of using Google street view (GSV) for pest monitoring in an urban setting includes easy identification and detection of invasive pests on trees, cost effectiveness and time efficiency compared to traditional methods. The efficacy of using GSV imagery to map and monitor the spread of PSHB-FD infestation on trees in the City of Johannesburg (CoJ) was therefore evaluated. A total of 1137 trees were surveyed using GSV for PSHB-FD infestation on images from 2010 to 2022. The field survey and GSV methods showed good agreement in classifying PSHB-FD infestation on two Platanus species. Finally, GSV is species specific and is only applicable for certain tree species such as Platanus x acerifolia , Platanus racemosa and Acer buergerianum where symptoms of infestation are visible in GSV images. Findings from this study showed that PSHB-FD infestation was present in the CoJ in 2017, indicating the importance of the method in effectively tracing back the actual date of the first infestation in the city. GSV also proved to be a useful method for mapping and monitoring PSHB-FD infestation on sentinel Platanus trees in Johannesburg, suggesting that it could serve as a viable alternative to field surveys.