Young plants are attacked by Ophiomyia phaseoli, Aphis craccivora, and Planococcus citri.    From Wordnik.com.  [Chapter 7] Reference

Other extensively widespread pests which infest the yam tuber during storage are mealy bugs and yam mealy bugs (Aspidiella hartii and Planococcus dioscorea).    From Wordnik.com.  [4 Yams] Reference

Planococcus citri, and (in Papua New Guinea) P. dioscoreae, feed on the tubers and roots of yams, and can multiply to considerable numbers, causing shrivelling of the stored tubers.    From Wordnik.com.  [Chapter 37] Reference

Planococcus lilacinus ladyfinger taro.    From Wordnik.com.  [Chapter 7] Reference