Efficacy and biases In inspections for biosecurity threats In South Africa

Abstract

Trade in agricultural commodities is beneficial economically, but it carries risks, as alien agricultural pests can be imported into new regions. To manage this challenge, inspections of agricultural produce are performed at South Africa’s ports of entry. This study aims to evaluate the efficacy and identify biases in agricultural inspections on fresh fruit imports to South Africa. Pest interception data for quarantine and non-quarantine insects from fresh fruit imports between 2008 and 2018 from the South African Department of Agriculture, Land reform and Rural Development was analysed. For this analysis, trade pathways were analysed to have three components: the country of origin (o); agricultural commodity (c); and insect species (i). For each trade pathway, the trade volume to be inspected (TV) and the trade volume to be inspected per interception (TVPI) were calculated using import data and host distribution data. TV is an indicator of the risk of importing a particular organism on a given pathway. TVPI can be used to identify pathways where the expected risk is high (high TV), but where the number of interceptions is lower than expected based on risk. During the assessed period there were 399 interceptions on 13 fruit types imported from 22 countries. Only 48% of interceptions were identified to the species level, with quarantine species accounting for far fewer interceptions (45 individuals of 12 species) than non-quarantine species (354 individuals of 75 species). Control bias was observed in quarantine species, indicating the need to improve inspection strategies and sampling efforts to increase the effectiveness of border controls in South Africa. To promote good biosecurity, further studies should be conducted to analyse control bias based on sampling effort data than interceptions relative to TV, to improve phytosanitary controls on agricultural imports, especially fresh fruit.