Horizon scanning for invasive arthropods with the potential to threaten crop production industry in South Africa

Abstract

Invasive alien pests have caused a considerable negative impact on socio-economic growth and development in the South African agricultural sector. An effective strategy called horizon scanning has recently gained momentum in assessing the preparedness level for prospective changes or threats by invasive alien pests. The study was conducted to identify and prioritize pests already occurring elsewhere in Africa that are likely to be introduced in the Republic of South Africa as well as to develop pest risk analysis reports, pest risk management measures, surveillance procedures, regulatory framework and pest response strategies. The current study revealed that out of 97 known alien invasive arthropods, only 22 invasive pests are considered to have the highest potential risk of being introduced to South Africa. Among these, 8 were Hemiptera, 6 Coleoptera, 5 Diptera, 2 Lepidoptera, one Thysanoptera. Most arthropods (80%) were likely to arrive as contaminants on plant commodities. The pests with the highest scores were Maconellicoccus hirsutus, and Thrips palmi. Both M. hirsutus, and T. palmi have higher potential for entering and establishing in the country as they are important pests of plants. Zygodacus cucurbitae, Bactrocera latifrons, B. zonata, Paracocus marginatus, and Pectinophora gossypiella were the second most economic pests in terms of likelihood of entry and establishment in the country. Complete pest risk assessments and surveillance for the presence or introduction of pests in the country were the most frequently recommended phytosanitary measures against highly prioritised pests with the highest scores. Plants and plant products are the primary pathways for these prioritised pests.