Impacts of the cyromazine emergence inhibition procedure of Bactrocera dorsalis on Fopius arisanus: implications for the biological control of diptera pest.

BACKGROUND: Fopius arisanus (Sonan) is an important egg-pupal endoparasitic wasp of Bactrocera dorsalis (Hendel). As traditional method of sorting nonparasitic B. dorsalis from parasitic wasps is labor-intensive, requires specific equipment and poses the risk of spreading fertile hosts, the development of a more convenient, economical and safe sorting procedure is important. RESULTS: The optimal cyromazine emergence inhibition procedure (CEIP) involved facilitating the pupation of B. dorsalis mature larvae (Bdml) in 3 mg kg-1 cyromazine sand substrate (CSS) for 48 h. When the Bdml that had been exposed to F. arisanus during the egg stage were treated with 3-7 mg kg-1 CSS for 48 h, no negative effects on the emergence parameters of parasitoids were observed. Treatment with 3-4 mg kg-1 CSS had insignificant effects on the biological and behavioral parameters of F. arisanus. However, treatment with 5-6 mg kg-1 CSS adversely affected the fecundity and antennating activity of the wasps; specifically, 6 mg kg-1 CSS negatively affected the lifespan and flight ability of wasps. Fortunately, no transgenerational effects on these parameters were observed in the progeny. Regarding the nutrient reserves of both sexes of F. arisanus, significant dose-dependent effects were observed. Moreover, 5-6 mg kg-1 CSS significantly reduced the protein and carbohydrate content in F. arisanus; in particular, 6 mg kg-1 CSS notably reduced the lipid content. CONCLUSION: CEIP provides a more flexible, economical and safe mass-release program for F. arisanus. In addition, it has profound implications for the biological control of other dipteran pests. © 2024 Society of Chemical Industry.

Effects of low-concentration spinetoram wax-based bait stations on Bactrocera dorsalis (Diptera: Tephritidae).

Spinetoram wax-based bait station (SWBB) is a maintenance-free, long-lasting, and eco-friendly management measure for Bactrocera dorsalis. However, the impacts of low-concentration spinetoram on B. dorsalis have not yet been determined. Therefore, our study aimed to determine the impacts of low-concentration SWBBs on the biology, demographics, detoxifying enzymes, and gut microorganisms of B. dorsalis. Our results showed that low-concentration SWBBs posed dose-dependent effects on the lifespan and fecundity of B. dorsalis adults. Both the LC10 and LC30 treatments significantly reduced the fecundity, while only the latter led to significant deleterious effects on the longevity of adults. Transgenerational bioassays revealed that exposure to LC30 significantly affected the development period of larvae and pupae as well as the livability of pre-adult stage of the progeny. However, except for the ovipositional period, no significant effects on the biological traits of F1 adults were observed. In terms of the F1 demographic parameters, dose-dependent effects were observed. Moreover, both the LC10 and LC30 treatments significantly extended the mean generation time, while the latter remarkably decreased the finite and intrinsic rates. Additionally, the significant induction of CarE activity by the LC10 and LC30 treatment was maintained until 24 and 48 h respectively. The CYP450 O-deethylation activity in the LC30 treatment was significantly enhanced at 24 and 48 h intervals when compared to the control. Regarding the intestinal bacterial community, after B. dorsalis adults were exposed to low-concentration SWBBs, the relative abundances of Providencia and Vagococcus were significantly increased, whereas those of Lactococcus and Brachyspira experienced a significant decrease. The obtained results are expected to serve as a foundation for the application of spinetoram in "lure-and-kill" strategies against B. dorsalis.

A new species of Diachasmimorpha Viereck (Hymenoptera: Braconidae: Opiinae) from China.

Diachasmimorpha anshunensis sp. nov., a koinobiont endoparasitoid of larvae of Zeugodacus tau (Walker) (Tephritidae: Diptera), is discovered from Guizhou (Southwest China) and is described by multiple forms of evidence. Morphological characteristics, photographs, and molecular data differentiating it from similar species are provided. Several biological characteristics of this new parasitoid, observed in a laboratory setting, are also provided as evidence to separate it from the most similar species in appearance.

The complete mitochondrial genome of Fopius arisanus (Sonan 1932) (Hymenoptera: Braconidae).

Fopius arisanus (Sonan, 1932), an important egg parasitoid of several notorious tephritid pests, plays a key role in biological control programs. In the present study, the whole mitochondrial genome of F. arisanus was sequenced and characterized. The mitogenome of F. arisanus is 16,425 bp in length with 14.94% GC content, and contains 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), and two ribosomal RNA genes (rRNAs). The phylogenetic trees demonstrated that F. arisanus is sister group to Psyttalia concolor, P. humilis, P. lounsburyi and Diachasmimorpha longicaudata.

Quantification and Impact of Cold Storage and Heat Exposure on Mass Rearing Program of Bactrocera dorsalis (Diptera:Tephritidae) Genetic Sexing Strain.

Cold storage and heat exposure are crucial components of tephritid fruit fly mass-rearing programs, as they influence the development and fitness traits of produced flies. This work investigated the effects of cold storage on the pupal developmental parameters and quality of Bactrocera dorsalis (Hendel) genetic sexing strain (GSS) adults. Furthermore, the impact of short-term thermal exposure on the fecundity of B. dorsalis (GSS) that also underwent pupal cold storage was examined. Our results show that pupal development time, emergence rate, partial emergence rate, flight ability and fecundity were significantly affected by low temperature and pupal age and their interaction. Pupal cold storage did not pose negative impacts on the mating competition and response to methyl eugenol (ME) in the males. In addition, compared with the adults that were subjected to the same pupal storage protocol (five-day-old pupae stored at 13 °C), adult exposure to 41 °C for 1 h showed significant reparative effects on fecundity. In summary, the cold storage procedure of B. dorsalis (GSS) pupae has the potential to improve the flexibility and efficiency of mass-rearing schedules. Furthermore, short-term thermal exposure showed reparative effects on the fecundity costs induced by pupal cold storage in B. dorsalis (GSS).

Tyrosine hydroxylase is crucial for pupal pigmentation in Zeugodacus tau (Walker) (Diptera: Tephritidae).

Tyrosine hydroxylase (TH) is the initial enzyme responsible for cuticle sclerotization and pigmentation in many insect species, but to date, no direct functional studies have focused on TH in Zeugodacus tau. Here, the 3336-bp full-length cDNA of TH was isolated from Z. tau, a notorious horticultural pest infesting fruits and vegetables. qRT-polymerase chain reaction revealed that ZtTH transcripts were highly abundant at the time of pupal tanning and during adult emergence and were expressed in the midgut, integument and head of molting larvae. The pupation and eclosion rates gradually decreased when the 1st-instar larvae were fed diets containing higher concentrations of the TH inhibitor 3-iodo-tyrosine (3-IT). Moreover, pupal weights were significantly decreased, and abnormal uncolored phenotypes were observed after 20 mg/g 3-IT was incorporated into the diet. In addition, the suppression of TH function (mediated by RNA interference) led to a decrease in TH mRNAs and eclosion rates, accompanied by less-pigmented phenotypes. There was a severe impairment of larval-pupal cuticle tanning, leading to pupae with less yellowish pigment or that were completely white and transparent, when we injected 2 µL of 24.4 mM or 73.27 mM 3-IT into 3rd-instar larvae or prepupae. These results suggest that TH is an important enzyme for the normal growth and pupal pigmentation of Z. tau and that TH is a potential gene target for use in the control of Z. tau.

Molecular identification of cultivable bacteria in the gut of adult Bactrocera tau (Walker) and their trapping effect.

BACKGROUND: It has been shown that some bacteria can attract their hosts. Our research aimed to identify cultivable bacterial isolates in the guts of sexually mature adult female and male Bactrocera tau and to evaluate their utility in trapping of B. tau. RESULTS: Forty-one strains of bacteria were isolated and identified from B. tau with morphological, physiological, biochemical and 16S rDNA analysis. The dominant bacterial genera shared by both females and males were Enterobacter, Providencia and Serratia. Thirteen bacterial isolates selected from female and male B. tau adults were cultured, and the attractiveness of bacterial fermented liquid and autoclaved supernatants from these strains to B. tau adults was tested. The laboratory test showed that both the autoclaved supernatants and fermented liquid could attract male and female B. tau, and the former was substantially more effective, with the autoclaved supernatants from all strains being significantly more attractive to adult B. tau. BF16, BF(12), BF23 and BF(32) were the most attractive bacteria to 8-day-old and sexually mature B. tau. Furthermore, the results of a subsequent field cage test showed that BF(12), BF23, and BF(32) were significantly more attractive to B. tau adults. CONCLUSION: These results provide useful information for the development of bacterial biocontrol agents and their application as insecticides. © 2018 Society of Chemical Industry.

[Evaluation of norovirus rapid detection kit].

OBJECTIVE: Evaluating the accuracy and safety as well as the equivalence compared with the control kit of RIDA QUICK Norovirus detection kit(R-Biopharm, Germany). METHODS: Based on the results of commercially available IDEA Norovirus detection kit (ELISA), the sensitivity and specificity and accuracy of RIDA QUICK Norovirus detection kit (immunochromatographic assay) were evaluated. RESULTS: The sensitivity and specificity of RIDA QUICK Norovirus detection kit were 98.4% and 92.4%, and the accuracy was 97.6% compared with the control kit. CONCLUSION: RIDA QUICK Norovirus detection kit has good sensitivity and specificity for the detection of norovirus antigens.