Preliminary Studies on Inherited Sterility for Field Management of Diamondback Moth (Plutella xylostella) (Lepidoptera: Plutellidae) on Crucifers in Ghana

The diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae) is the most destructive insect pest of crucifers in Ghana and the world over. It is estimated to cost about USD 1 billion to control annually worldwide. Reliance on chemicals as the sole control measure for diamondback moth has resulted in the development of a myriad ofproblems including resistance, high residue levels on produce, destruction of natural enemies and pest resurgence among others. Inherited sterility in Lepidoptera insects has a potential for suppressing DBM populations. We conducted this study to evaluate the use of the technique to manage the diamond back moth in Ghana. When 3 – 4 day old pupae were treated with 130 Gy and 150 Gy of gamma radiation, 47% and 46% respectively of the male pupae developed as normal adults whiles 40% and 17% respectively of the female pupae developed as normal adults. However, radiation-induced reductions in fecundity and egg viability were expressed in the parental and first filial (F ) generations. Sterility exceeded 1 66% in the treated parental male and 92% in the treated parentalfemale in both treatments as compared with 78% and 95% in treated F male and female, respectively. The sex ratio was 1 skewed in favour of males in the parental progeny. These results indicate the possibility of using inherited sterility for DBM control.Keywords: Diamondback moth Plutella xylostella, irradiation, inherited sterility, F 1 sterility