The Wheat Curl Mite (Aceria tosichella, Prostigmata: Eriophyidae) Could Establish in South Africa

Biological invasions by agricultural pests can have serious negative impacts, including decreases in crop yield and economic losses. The MT-1 and MT-8 genotypes of the wheat curl mite (Aceria tosichella) (hereafter ‘WCM’ refers to these two genotypes) are globally distributed pests of wheat and maize that have not been recorded in South Africa. This study examined whether WCM could be introduced to, and establish in, South Africa. Trade data were used to determine whether viable pathways of introduction are present. A species distribution model and data on wheat and maize production were used to determine whether WCM could establish where its hosts are grown. WCM is most likely to be introduced to South Africa as a contaminant of maize from Argentina, Brazil, Uruguay, and USA; on live plant imports from China and Germany; and on seed imports from Brazil and Australia. Some of these pathways are not currently prominent, but could increase in the future. Parts of South Africa were predicted by the species distribution model to be climatically suitable for WCM, and within some of these areas the host crops are grown. Therefore, if WCM is introduced, it is likely to establish and cause extensive damage to agriculture. We recommend that WCM be considered for inclusion in South Africa's import conditions as a quarantine pest.