Biological characteristics and occurrence patterns of Heortia vitessoides

Heortia vitessoides Moore has been a serious defoliating pest of Aquilaria sinensis forests in recent years.In southern China the larvae of H.vitessoide feed solely on the leaves of A.sinensis.The biological characteristics and patterns of occurrence of H.vitessoide were studied in both the laboratory and field.The moth had eight generations per year in Huazhou,Guangdong Province and over-wintered as pupae.The adults began to emerge in mid-April.Overlapping of generations began in the last ten days of May,and was greatest between the first and second generations.The duration of a single generation was 28- 32 days,and the over-wintering stage lasted three months.Eggs were laid on the back of young leaves of A.sinensis,and their development took 3- 4 days.The hatching rate of eggs was over 95%.The larvae had 5 instars and small larvae fed in groups.From the 3rd instar,the larvae began to disperse to feed.Mature larvae pupated in a cocoon at a depth of 2 cm in soil or fallen leaves.The duration of the pupal stage was 8- 15 days.The peaks of adult emergence occurred at night and adults displayed strong phototaxy.