The fall armyworm, Spodoptera frugiperda (J.E. Smith), is a noctuid moth native to the tropical and subtropical Americas that has successfully invaded Africa and Asia, where it is has become a serious threat to food security as a pest of cereals and other crops. Biological control is an environmentally friendly means of combating the pest and contributes to an integrated pest management approach. In our study, two egg parasitoid species (Trichogramma mwanzai and Trichogrammatoidea lutea) found in parasitized fall armyworm eggs in Zambia were identified by using a combination of both molecular and morphological characteristics. To evaluate their potential and efficiency on 0- to 2-day-old fall armyworm eggs, we compared their parasitism capabilities with three Trichogramma species native to China (T. ostriniae, T. leucaniae and T. japonicum) under laboratory conditions. The results showed that both parasitoid species would accept 0-, 1- and 2-day-old fall armyworm eggs, and complete their development successfully. Trichogramma mwanzai and T. lutea preferred parasitizing 0- and 1-day-old eggs over 2-day-old eggs. Trichogrammatoidea lutea females supplied with fall armyworm eggs produced the highest parasitism rate of host eggs among the five tested species, while T. mwanzai had the shortest developmental time on all test age eggs. In general, T. lutea was the best performing of the five species when reared on fall armyworm eggs, while T. japonicum was the worst. There were no significant differences, however, in percent emergence in the five test species when reared on fall armyworm eggs.

The complete mitochondrial genome of a pyraloid species, Palpita hypohomalia, was sequenced and analyzed. This mitochondrial genome is circular, 15,280 bp long, and includes 37 typical metazoan mitochondrial genes (13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes) and an A + T-rich region. Nucleotide composition is highly biased toward A + T nucleotides (81.6%). All 13 protein-coding genes (PCGs) initiate with the canonical start codon ATN, except for cox1 which is CGA. The typical stop codon TAA occurs in most PCGs, while nad2 and cox2 show TAG and an incomplete termination codon T, respectively. All tRNAs have a typical clover-leaf structure, except for trnS1 (AGN) which lacks the dihydrouridine (DHU) arm. Comparative mitochondrial genome analysis showed that the motif "ATGATAA" between atp8 and atp6, and the motif "ATACTAA" between trnS2 and nad1 were commonly present in lepidopteran mitogenomes. Furthermore, the "ATAG" and subsequent poly-T structure, and the A-rich 3' end were conserved in the A + T-rich regions of lepidopteran mitogenomes. Phylogenetic analyses based on our dataset of 37 mitochondrial genes yielded identical topology for the Pyraloidea, and is generally identical with that recovered by a previous study based on multiple nuclear genes. In a previous study of the Crambidae, the Evergestinae was synonymized with Glaphyriinae; the present study is the first to clarify their close relationship with mitogenome data.

Background: Spodoptera frugiperda, a major migratory and invasive pest, inflicts significant yield loss on rice and maize in China. As part of an integrated pest management system, biological control agents can be used against S. frugiperda , especially egg parasitoids. However, limited evidence exists regarding the combined and persistent effects of various pest control products on those parasitoids. Results: This study examined the selective and persistent toxicity of seven approved pesticides [chlorantraniliprole, lufenuron, emamectin benzoate, spinetoram (synthetic pesticides), Mamestra brassicae Nuclear Polyhedrosis Virus (MabrNPV), Bacillus thuringiensis (Bt) (biopesticides) and a chlorantraniliprole-lufenuron mixture (3:1) treatment] to five species of egg parasitoids, namely Trichogramma dendrolimi , Trichogramma chilonis , Trichogramma mwanzai , Trichogrammatoidea lutea , and Telenomus remus . The residual toxicity tests revealed that spinetoram showed high toxicity to T. mwanzai , T. dendrolimi , and T. chilonis in adults stage with mortality of over 92.6%, but caused low mortality in T. lutea (64.9%) and T. remus (49.2%) when used at the recommended rate. However, after treated by chlorantraniliprole, lunefuron, chl. + luf. (3:1), MabrNPV, and Bt, the mortality rates of all tested parasitoid adults were below 25% (lunefuron lower than 10%). A 3-day emamectin benzoate treatment caused 90% mortality in T. mwanzai , T. lutea , T. dendrolimi , and T. chilonis adults. The 3:1 mixture of chlorantraniliprole and lufenuron did not affect the lifespan of T. mwanzai and T. lutea . Chlorantraniliprole exhibited exceptional safety for all developmental stages (adult, egg, and pupa) of the five egg parasitoid species. A risk analysis indicated that chlorantraniliprole, MabrNPV, Bt, and the 3:1 mixture had the least toxicity to the five tested parasitoid adults, followed by lufenuron. Conversely, spinetoram and emamectin benzoate displayed moderate toxicity to adults of all tested parasitoid species. Conclusion: Our findings indicate that chlorantraniliprole is safe for the five egg parasitoids species studied even after prolonged use and can be used in conjunction with lufenuron. However, spinetoram and emamectin benzoate had the potential to be harmful to these parasitoids.

The soybean aphid, Aphis glycines Matsumura, is one of the most destructive pests affecting soybean production, frequently inflicting substantial economic losses. In this study, an optimized MaxEnt model was employed to predict the habitat suitability of A. glycines , its host plant Glycine max , and four key natural enemies ( Harmonia axyridis , Chrysopa pallens , Episyrphus balteatus , and Lysiphlebia japonica ). Furthermore, the overlaying ranges of suitable habitats of A. glycines and these natural enemies were identified. Results indicated that the area under the receiver operating characteristic (AUC) values of the six models ranged from 0.856 to 0.981 and the true skill statistic (TSS) values from 0.470 to 0.733. The highest contributing variables for the models of A. glycines , G. max , H. axyridis , C. pallens , E. balteatus , and L. japonica were BIO04 (temperature seasonality), BIO18 (precipitation of warmest quarter), BIO14 (precipitation of driest month), BIO01 (annual mean temperature), BIO18, and BIO17 (precipitation of driest quarter), respectively. Different natural enemies exhibited distinct niche overlaps with A. glycines in spatial distribution. For instance, the overlaying range between A. glycines and H. axyridis were distributed across East China, Korea, and Japan, whereas those between A. glycines and L. japonica were mainly concentrated in parts of South China and most of Japan. The differences suggest that priority regions for the release of different enemies can be identified to potentially control A. glycines . Compared with previous modeling study on A. glycines , this study adopted a MaxEnt parameter optimization approach and defined the suitable habitats of A. glycines under the presence of its host G. max . The results could enhance the understanding of the potential distribution of A. glycines and effectively facilitate the selection and application of natural enemies for regional biological control of this pest.