Ceriagrion fallax is ubiquitous in south China and is particularly easy be found in some rice fields. In this study, we sequenced and analyzed the complete mitochondrial genome (mitogenome) of C. fallax . This mitogenome was 15,350 bp long and encoded 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs) and two ribosomal RNA unit genes (rRNAs). The nucleotide composition of the mitogenome was biased toward A and T, with 74.0% of A + T content (A 42.1%, T 31.9%, C 14.6%, G 11.4%). Gene order was conserved and identical to most other previously sequenced Zygoptera dragonflies. Most PCGs of C. fallax have the conventional start codons ATN (seven ATG, two ATT, and two ATC), with the exception of nad3 and nad1 (TTG). Except for four PCGs ( cox1 , cox2 , cox3 , and nad5 ) end with the incomplete stop codon T––, all other PCGs terminated with the stop codon TAA. Phylogenetic analysis showed that C. fallax got together with the same family species ( Agriocnemis femina , Enallagma cyathigerum , Ischnura elegans , Ischnura pumilio ) with high support value. The relationships (Megapodagrionidae + ((Calopterygidae + (Euphaeidae + Pseudolestidae)) + (Coenagrionidae + Platycnemididae))) were supported within Zygoptera.

Evergestis extimalis (Scopoli) is a significant pest of spring oilseed rape in the Qinghai-Tibet Plateau. It has developed resistance to many commonly used insecticides. Therefore, biopesticides should be used to replace the chemical pesticides in pest control. In this study, the effects of ice-nucleation-active (INA) microbes (Pseudomonas syringae 1.7277, P. syringae 1.3200, and Erwinia pyrifoliae 1.3333) on E. extimalis were evaluated. The supercooling points (SCP) were markedly increased due to the INA bacteria application when they were compared to those of the untreated samples. Specifically, the SCP of E. extimalis after its exposure to a high concentration of INA bacteria in February were -10.72℃, -13.73℃, and -14.04℃. Our findings have demonstrated that the trehalase (Tre) genes were up-regulated by the application of the INA bacteria, thereby resulting in an increased trehalase activity. Overall, the INA bacteria could act as effective heterogeneous ice nuclei which could lower the hardiness of E. extimalis to the cold and then freeze them to death in an extremely cold winter. Therefore, the control of insect pests with INA bacteria goes without doubt, in theory.