Aspidiella hartii (Cockerell 1895) (Hemiptera: Diaspididae) on yam (Dioscorea spp.) tubers: a new pest regularly entering the European part of the EPPO region

Yam is an important West African crop and is an inexpensive source of carbohydrate. Many people of Central African origin living in South Italy buy imported tubers to prepare preferred recipes. Aspidiella hartii (Cockerell) infests yam tubers marketed in Bari (South Italy). Adult female scales on tuber bark are brownish, subcircular and about 1.2 mm wide. Ventral shields (“flags”) from dead individuals are also abundant. The pest reproduces during storage and covers the tuber. Removal of plant sap shrivels the tubers during their trade, reducing quality, viability and marketability of the product. Severe A. hartii infestation of tubers can also inhibit their resprouting or kill the plant in the country of origin. Dipping yam in concentrated pyrethroids, or organophosphate insecticide, storage in sawdust, paddy husk or wood ash or paraffin wax coating may help to control the pest, although dipping in pyrethroids or organophosphate insecticide is not allowed in Europe. The armoured scale also infests Colocasia sp. (Taro, Araceae) and Ipomoea batatas (L.) Lam. (sweet potato, Convolvulaceae) causing similar damage. The presence of A. hartii host plant in Europe and the possible host-shift of this pest to other crops in the region pose a risk for EPPO countries.