Evaluation of an artificial pudding diet for rearing Tetraphleps galchanoides (Hemiptera: Anthocoridae)

Tetraphleps galchanoides Ghauri is an important natural enemy to the hemlock woolly adelgid (HWA), Adelges tsugae (Annand). An artificial pudding diet (APD) mainly consisting of protein, fat and carbohydrates was prepared with the production rate of 74.5%, the moisture content of 8.6%, and the score of sensory evaluation of 81.7. To evaluate the efficiency of APD for rearing T. galchanoides, the developmental duration and survival rate of nymphs and the reproductive capacity of T. galchanoides fed on APD were observed in the laboratory, and the predation rates of nymphs and adults reared with APD were also investigated in the field. The results showed that there was no significant difference (P0.05) in the developmental duration between T. galchanoides nymphs fed on APD (103.2±6.5 d) and on HWA (105.7±8.4 d). The survival rate of T. galchanoides nymphs fed on APD (73.2%) was lower than that fed on HWA (77.4%). The acquisition rates of T. galchanoides adults of the 1st, 2nd, and 3rd generations fed on HWA were the same with those fed on APD. There was no significant difference in pre-oviposition period, oviposition period, and oviposition amount between T. galchanoides adults fed on APD and those on HWA. Significant differences were found between the hatching rates of eggs laid by female adults fed on APD (85.8%) and HWA (71.4%), and in the longevity between female adults fed on APD (51.9±4.0 d) and HWA (37.4±2.6 d). T. galchanoides fed on APD preyed HWA effectively in the field. Thus, APD can be used for the mass rearing of T. galchanoides, which can be applied for biological control of HWA on a large scale.