Thermal development of the endoparasitoid Aphelinus maculatus Yasnosh (Hymenoptera: Aphelinidae) parasitizing Myzus persicae Sulzer (Homoptera: Aphididae).

The aphid parasitoid, Aphelinus maculatus Yasnosh, was first documented in China in 2016. It is important to make clear of the effects of temperatures on the development of this aphid parasitoid for the future using as a aphid biological control agent. So the thermal requirements, lower developmental threshold (t), thermal constant (K), upper developmental threshold (Tm) and optimum developmental temperature (To) for the egg-mummy, mummy-adult and egg-adult periods of A. maculatus were established under the laboratory conditions. The studies were conducted at five constant temperatures (13, 18, 23, 28, and 33 °C) and with a 16 L: 8D photoperiod. Lower developmental threshold (t) and thermal constant (K) were estimated by fitting linear model. Upper developmental threshold (Tm) and optimal developmental temperature (To) were estimated by fitting Logan I non-linear model. The results turned out that the lower (t) and the upper developmental thresholds (Tm) for egg-adult period were 5.59 °C and 28.17 °C, respectively. The thermal constants (K) for egg-mummy, mummy-adult, and egg-adult periods were estimated at 121.51, 127.88, and 243.90 degree-days, respectively. The optimal developmental temperature (To) for egg-adult period was 27.45 °C calculated by the model, but the survival rate was only 40.68% at the temperature of 28 °C. The highest survival rate was 74.32% at temperature of 23 °C, implying that A. maculatus preferentially developed at the temperate regions of temperature.

Polyhedrin gene sequence and phylogenetic analysis of a nucleopolyhedrovirus isolated from Orgyia ericae Germar.

Molecular characterization of a nucleopolyhedrovirus (NPV) isolated from the diseased larva of Orgyia ericae Germar was firstly analyzed. The genomic size of O. ericae NPV was estimated to be 134.6 kb by restriction endonuclease analysis. The gene encoding the major structural protein, polyhedrin, was cloned and sequenced. Phylogenetic analyses using polyhedrin sequences revealed that O. ericae NPV (OeNPV) was a member of the Group II NPVs and was closely related to the BusuSNPV and OpSNPV cluster. Electron microscopic observations confirmed that OeNPV was a single nucleocapsid type virus (SNPV).