昆虫病原微生物是害虫综合治理的重要措施,但其防治效果不稳定、速效性差、自然流行慢,因此探索增强昆虫病原生物流行技术是提升其防治效果的重要手段.自传播技术利用昆虫自身传播病原微生物以控制害虫种群数量,该技术提高了昆虫病原微生物在田间的传播效率和精准防控效果,是目前害虫防治具有开发潜力的技术之一.本文阐述了国内外关于结合信息物质的昆虫病原微生物自传播技术研究进展,系统介绍了自传播技术的原理、昆虫病原微生物类群、防治对象和装置等,并对该技术未来发展趋势进行了展望,以期为提高昆虫病原微生物防控害虫效果提供新思路.

The wheat midge,Sitodiplosis mosellana,is a serious pest of wheat worldwide.In North America,management of S.mosellana in spring wheat relies on the timely application of pesticides,based on midge adults levels caught in pheromone traps or seen via field scouting during wheat heading.In this context,biopesticides can be an effective alternative to pesticides for controlling S.mosellana within an Integrated Pest Management program.A field study using insect pathogenic fungus Beauveria bassiana GHA,nematode Steinernemafeltiae with Barricade polymer gel 1％,pyrethrin,combined formulations of B.bassiana GHA and pyrethrin,Jasmonic acid (JA) and chlorpyrifos (chemical check)was performed to determine to which extent they affect midge larval populations,kernel damage levels,grain yield,and quality,and the impacts on adult parasitoid Macroglenes penetrans populations.The results indicated that biopesticides JA and S.feltiae were the most effective in reducing larval populations and kernel damage levels,and produced a higher spring wheat yield when compared to the water control at both study locations (East Valier and North Valier,Montana,USA).Increased test weight in wheat had been recorded with two previous biopesticides at East Valier but not for North Valier,when compared over water control.These results were comparable in efficacy to the chlorpyrifos.This study also suggested that B.bassiana and pyrethrin may work synergistically,as exemplified by lower total larval populations and kernel damage levels when applied together.This study did not demonstrate the effect of any treatments on M.penetrans populations.

Whiteflies (Bemisia tabaci) are polyphagous invasive hemipteran insects that cause serious losses of important crops by directly feeding on phloem sap and transmitting pathogenic viruses.These insects have emerged as a major threat to global agriculture and food security.Chemically synthesized insecticides are currently the only option to control whiteflies,but the ability of whiteflies to evolve resistance against insecticides has made the management of these insects very difficult.Natural host-plant resistance against whiteflies identified in some crop plants has not been exploited to a great extent.Genetic engineering approaches,such as transgenics and RNA interference (RNAi),are potentially useful for the control of whiteflies.Transgenic plants harboring insecticidal toxins/lectins developed via nuclear or chloroplast transformation are a promising vehicle for whitefly control.Double-stranded RNAs (dsRNAs) of several insect genes,delivered either through microinjection into the insect body cavity or orally via an artificial diet and transiently or stably expressed in transgenic plants,have controlled whiteflies in model plants and in some crops at the laboratory level,but not at the field level.In this review,we highlight the merits and demerits of each delivery method along with strategies for sustained delivery of dsRNAs via fungal entomopathogen/endosymbiont or nontransgenic RNAi approaches,foliar sprays,root absorption or nanocarriers as well as the factors affecting efficient RNAi and their biosafety issues.Genome sequencing and transcriptome studies of whitefly species are facilitating the selection of appropriate genes for RNAi and gene-editing technology for the efficient and resilient management of whiteflies and their transmitted viruses.

Basic helix-loop-helix(bHLH)transcription factors play an important role in a wide range of metabolic and developmental processes in eukaryotes,and bHLH pro-teins also participate in immune responses,especially in plants.However,their roles in insects upon entomopathogen infection are unknown.In this study,54 bHLH genes in 41 families were identified in a polyphagous pest,Spodoptera litura,including a new bHLH gene in group B,which is specifically present in Lepidoptera and was thus named Lep.The conserved amino acids in the bHLH domain,structural architecture,and chromoso-mal distribution of bHLH genes in S.litura were analyzed.The bHLH genes in Plutella xylostella and Apis mellifera were also updated,and genome-wide comparison and phy-logenetic analysis of bHLH members in 5 holometabolous insects were performed.The expression profiles of S.litura bHLH(SlbHLH)genes in 3 tissues at different develop-mental stages and their responses to S.litura nucleopolyhedrovirus(SpltNPV),Nomuraea rileyi(Nr),and Bacillus thuringiensis(Bt)infection were investigated.More SlbHLHs in group B were expressed and differentially expressed during pathogen infections,and SlbHLHs tended to be downregulated in the midgut of S.litura larvae after B.thuringien-sis treatment.Our study provides an overview of bHLH family members in S.litura and their responses to different pathogens used for pest biocontrol.These findings on bHLH members may contribute to uncovering the mechanism of host-pathogen interaction.