Table 1 Major factors contributing to SPW infestation

Pest biology

Cryptic life cycle which renders subterranean stages undisclosed or inaccessible

Agronomic practices

Pest build-up due to in-field debris of infested sweetpotato; plant stressors due to inadequate water, leading to cracks and pest access to roots; inadequate soil nutrients, or competition with weeds

Pest reservoir population

Ubiquitous pest presence in diverse set of alternative hosts, adjacent to fields locally and area-wide, which support a continual influx of the pest population

Planting material

Lack of certified clean planting material, or uniform access to clean planting material, insufficient and informal distribution channels for clean planting materials

Economics

Inability to invest in or access available control options

Pest awareness

Inadequate knowledge of the pest or the capacity to monitor its presence in the field