Effect of diet switching on the larval growth of Heteroneda billardieri (Crotch) (Coleoptera: Coccinellidae), predator of mango leafhopper in The Philippines

Heteroneda billardieri (Crotch) (Coleoptera: Coccinellidae) is a natural predator of the mango leafhopper (MLH), Idioscopus clypealis Lethierry (Hemiptera: Cicadellidae) in the Philippines. With regards to mass rearing and biological control efforts, the effects of diet switching between different prey species and artificial diet on the growth and development of H. billardieri larvae was studied. Cowpea aphid, Aphis craccivora Koch, Leucaena psyllid and Heteropsylla cubana Crawford were tested along with MLH and artificial diet. Based on results, switching diets of MLH and psyllid, MLH and artificial diet, and psyllid alone were less suitable for the larvae. However, larval development was faster when the larvae were fed just with either MLH or aphid alone. The most suitable diet was when the larvae were fed with MLH switched to aphid. The study proved that prey switching is an adaptation by H. billardieri and can enhance larval growth better than single diet alone. This might contribute positively to the outcome of mass rearing for biological control of MLH in the field.