1. Economic Impact of Tuta absoluta in Africa

Tomatoes are an important component of horticulture and a major pillar of sustainable development, with significant contribution to household and national food and nutritional security ^[1][2]. They are a cash crop grown for home consumption in the backyards of the majority homesteads across SSA and are an important source of vitamins ^[3]. Tomato production also significantly contributes to economic development ascribed to its high economic returns and ability to create employment (~60% of total labour force) and along the value chain ^[4][5]. About 170 million tonnes of tomatoes are produced worldwide ^[6][7]. Of this figure, Africa accounts for ~37.8 million tonnes annually. However, this figure is threatened by increased

T. absoluta damage ^[8], with downstream consequences on African socio-economic value chains and household livelihoods ^[9].

Tuta absoluta larvae attack almost all aerial parts of tomato plants, resulting in ~80–100% yield losses if left uncontrolled ^[10]. Larval feeding also reduces fruit quality through creating pin holes prone to secondary attack by pathogens, rendering them unmarketable ^[11]. Increased cost of production has been reportedly experienced by small- and large-scale farmers in Africa due to increased costs for pesticides ^[12]. For example, recent evidence suggests decreased tomato yields and increased production costs ^[9]. Highest losses are mostly experienced during early invasion owing to inadequate mitigation measures related to lack of preparedness ^[13]. Nigeria experienced up to 80% losses in tomato produce in 2016 due to unfamiliarity with the pest and management strategies ^[5]. This reduced supply and catapulted an estimated 10-fold increase in tomato prices due to the laws of demand and supply ^[14]. Similarly, following

T. absoluta invasion in South Africa (2016), pest-free countries banned importation of tomato and other Solanaceae crops from that country ^[15], resulting in significant economic losses. Similar losses have also been reported in South-western Angola ^[16]. Thus,

T. absoluta pest pressure has negatively affected agricultural enterprises in Africa through direct losses (crop damage) and indirect losses through increased costs in pest management ^[8].

Tuta absoluta remains a pest of quarantine importance in countries under the Inter-African Phytosanitary Council (IAPSC) and has been reported on the European and Mediterranean Plant Protection Organization’s (EPPO’s) A2 list as a regulated insect pest ^[17].

2. Tuta absoluta Invasion Pathways and Distribution in Africa

T. absoluta invasion ^[18]. International agricultural trade is a key long-distance transmission mode that may have contributed to a larger extent in the introduction of

T. absoluta into Africa, e.g., importation of fruits (e.g., tomatoes and egg plants) from pest-infested areas ^[8][19]. Other possible pathways for long-distance dissemination include production facilities and packaging materials (e.g., boxes, crates and pallets) from infested countries ^[20][21]. Hence, production facilities repack and distribute infested fruits, resulting in long-distance dissemination, reviewed in ^[22]. In addition, propagule material (e.g., seedlings), farm equipment and transportation vehicles from pest-infested areas are also possible pathways for long-distance transmission ^[18][19][23]. From the foregoing, the rapid spread across Africa may have been exacerbated by porous port of entries, weak phytosanitary regulations and ineffective early surveillance in the region ^[13]. Furthermore, natural factors (e.g., wind and water), larval crawling and adult flight are possible key short-distance dispersal pathways ^[18]. To date,

T. absoluta has been reported in 41 of the 54 African countries (see ^[8]). The pest has not yet been officially reported in a few central and south-western African countries ^[15][6]. However, cognisant of its widespread presence in Africa, this absence may be a consequence of lack of surveillance and pest detection mechanisms.