The European red mite, Panonychus ulmi, is among the most important mite pests in fruit orchards, where it is controlled primarily by acaricide application. However, the species rapidly develops pesticide resistance, and the elucidation of resistance mechanisms for P. ulmi has not kept pace with insects or with the closely related spider mite Tetranychus urticae. The main reason for this lack of knowledge has been the absence of genomic resources needed to investigate the molecular biology of resistance mechanisms. Here, we provide a comprehensive strand-specific RNA-seq based transcriptome resource for P. ulmi derived from strains susceptible and resistant to the widely used acaricide spirodiclofen. From a de novo assembly of the P. ulmi transcriptome, we manually annotated detoxification enzyme families, target-sites of commonly used acaricides, and horizontally transferred genes implicated in plant-mite interactions and pesticide resistance. In a comparative analysis that incorporated sequences available for Panonychus citri, T. urticae, and insects, we identified radiations for detoxification gene families following the divergence of Panonychus and Tetranychus genera. Finally, we used the replicated RNA-seq data from the spirodiclofen susceptible and resistant strains to describe gene expression changes associated with resistance. A cytochrome P450 monooxygenase, as well as multiple carboxylcholinesterases, were differentially expressed between the susceptible and resistant strains, and provide a molecular entry point for understanding resistance to spirodiclofen, widely used to control P. ulmi populations. The new genomic resources and data that we present in this study for P. ulmi will substantially facilitate molecular studies of underlying mechanisms involved in acaricide resistance.

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Transcriptome profiling of a spirodiclofen susceptible and resistant strain of the European red mite Panonychus ulmi using strand-specific RNA-seq.

Four different extracts of Aloe vera L. leaves were evaluated for acaricidal activity against female adults of carmine spider mite, Tetranychus cinnabarinus (Boisduval), by slide-dip bioassay. At 72 h after treatment, the acetone extract showed the strongest acaricidal activity with LC 50 value of 90 ppm. The LC 50 values for ethyl acetate, water, and ethanol extracts were 113, 340, and 391 ppm, respectively. The acetone extract was fractionated using a silica gel column. Among the twenty-two fractions obtained the fifth, tenth, eleventh, twelfth, fifteenth, and seventeenth fractions showed strong acaricidal activity, causing 80.39 to 92.16% mortality at 72 h after treatment. The tenth and eleventh fractions had the strong activity, with LC 50 values of 44 ppm and 33 ppm, respectively. The results suggested that A. vera has a great potential for development as a botanical acaricide for T. cinnabarinus control.

Acaricidal activity of Aloe vera L. leaf extracts against Tetranychus cinnabarinus(Boisduval) (Acarina: Tetranychidae)

In this study, we applied various developmental stages of zebrafish to address the potential environmental risk and aquatic toxicity of bromothalonil and flutolanil. This results demonstrated that the acute toxicity of bromothalonil to the three phases of zebrafish were 4.34 (embryo) < 3.27 (12 h old larvae) < 2.52 mg/L (adult fish) and that of flutolanil were 5.47 (embryo) < 4.09 (72 h old larvae) < 3.91 (12 h old larvae) < 2.70 mg/L (adult). Sublethal effects induced by both bromothalonil and flutolanil on zebrafish embryos were noted, including growth inhibition, abnormal spontaneous movement, slower heart rate, complete hatching failure, and morphological deformities. In addition, both bromothalonil and flutolanil could cause notochord deformation and short body length of larvae. This study provides a foundation for future investigation into the mechanism of bromothalonil and flutolanil toxicity in zebrafish.

Toxic Effects of Bromothalonil and Flutolanil on Multiple Developmental Stages in Zebrafish.

On the basis of the problem that the image background is simple and the traditional shooting equipment of fruit flies is too high, this study improved the convolutional neural network model. First, the authors changed Softmax classifier to support vector machine (SVM). Moreover, then used convolution layers for extracting features of fruit fly images. Finally, they fed features into SVM for training. Experiments show that the model has been classifying the Bactrocera dorsalis Hendel, Bactrocera cucurbitae, Bactrocera tau and Bactrocera scutellata with accuracy over 92.04%, accordingly making the effective classification of the complex background fruit fly images possible. Moreover, it also provides a good practical application prospect.

CNN–SVM: a classification method for fruit fly image with the complex background

Methanol extracts of nine plant species were evaluated for their ovicidal activity against the two-spotted spider mite Tetranychus urticae Koch in a bioassay under laboratory conditions. These plants and plant parts used in the study were Xanthium strumarium L. (fruits and leaves), Anthemis vulgaris L. (flowers and leaves), Humulus lupulus L. (flower buds), Chenopodium album L. (flowers and leaves), Melia azedarach L. (fruits), Eucalyptus camaldulensis Dehn (flower buds and leaves), Solanum nigrum L. (flowers, leaves and fruits), Styrax officinalis L. (seed coats, seeds) and Lolium perenne L. (flowers and leaves). The greatest mortality was caused by E. camaldulensis leaf extract (63.26%), followed by X. strumarium fruit (59.64%), X. strumarium leaf (57.45%), S. nigrum fruit (51.57%), A. vulgaris flower (46.80%) and S. officinalis seed extract (44.25%). Lolium perenne extract (flowers, leaves) caused the least mortality (24.40%). Azadirachtin at 10 g/l concentration was used as a chemical standard and caused 10.09% mortality. Our results show that some of these plant extracts have a potential for ovicidal activity on two-spotted spider mite eggs and are worth further investigation.

https://www.academicjournals.org/article/article1380730160_Yanar et al.pdf

Ovicidal activity of different plant extracts on two- spotted spider mite (Tetranychus urticae Koch) (Acari: Tetranychidae)

The bioactivities of ethanol extracts from twenty plants against Panonychus citri were measured in the laboratory with the glass plate dipping to find the strongest acaricidal plant.The results demostrated that Boenninghausenia sessilicarpa,Laggera pterodont,Humulus scanden and Rabdosia of ethanol extracts,of which LC50 were 0.9241,0.9827,0.9905 and 1.0196 mg·mL-1,respectively.The extracts of B.sessilicarpa possessed significantly ovicidal activity four extracts,of which LC50 was 1.7032 mg·mL-1.

Primary studies of acarocidal activity of twenty plants extracts against Panonychus citri.

Selection of resistance to amitraz and analysis of expression difference of cytochrome P450 genes in Panonychus citri (Acari: Tetranychidae).

Oriental fruit fly(Bactrocera dorsalis) is an important quarantine pest for fruits and vegetablesIt occurred in Yun-nan in recent years,causing significant economic lossesHanging traps in citrus orchards located in Yuanjiang and Huaning counties,Yunnan Province for trapping oriental fruit fly and monitoring systematically has been done for many yearsThe re-sults showed that the rampaging period was in June and July but a little bit earlier(around 10 d) in Huaning county and occurrence quantity was much severer in Yuanjiang countyBased on the monitoring data collected from 2003 to 2008 in-cluding trapped pests,and weather factors,temperature,humidity,precipitation,illumination etc2 prediction models were established using the method of simple regression and multifactorial stepwise regression respectivelyThese 2 models could accurately predict the occurrence quantity and period of oriental fruit flyFurthermore,the occurrence quantity and period of oriental fruit fly were closely related to the interaction among multi-factorsThe test results indicated that the model estab-lished by multifactorial stepwise regression was more credible than that by simple regression

Study on prediction mathematical model of occurrence quantity and period for oriental fruit fly (Bactrocera dorsalis)

In order to screen high-effective medicaments,23 fungicides were diluted to 200 mg/L separately,three fungicides were chosen which had stronger antimicrobial effect on the starain and the detemination of indoor toxicities was carried out.The results showed that the EC50 of benziothiazolinone,streptomycin and bromothalonil were 46.59,86.18 and 102.91 mg/kg,respectively.The benziothiazolinone had the highest growth inhibition toxicity against the pathogen.On comparison of the active ingredients of fungicides and their working mechanisms,the best fungicide was streptomycin.

Toxicity of three fungicides to Xanthomonas axonopodis pv. citri.

Objectives] To determine the olfactory response of Neoseiulus barkeri to volatiles released by citrus leaves that had been damaged by either Panonychus citri or piercing-sucking insects. [Methods] Common volatile compounds of citrus leave were qualitatively analyzed using GC-MS-liquid mass spectrometry. The relative retention index of each compound was determined and a library of the common citrus volatiles obtained constructed. In addition, volatiles from citrus leaves damaged by P. citri and sucking insects were collected and identified. Orientation responses of N. barkeri to volatiles were studied using a Y-tube olfactometer. [Results] Both the kinds, and the quantities, of volatiles from damaged leaves were notably different to those of the control. Furthermore, the volatiles from leaves damaged by P. citri were significantly different to those obtained 1期 胡军华等: 巴氏新小绥螨对柑桔全爪螨处理的枳橙叶片挥发物的行为反应 ·31· from leaves damaged by sucking insects. Both kinds of damage induced citrus leaves to release α-pineine, α-phellandrene and p-cymene. Insect damage dramatically increased the quantities of some volatiles, including cis-π-ocimene, myrcene, limonene and terpineol, but reduced that of others, including 2-ethyl-alcohol and Undecane. N. barkeri was obviously attracted to caproaldehyde, nonanal, octyl acetate, heptaldehyde and myrcene at the concentrations tested (P>0.05). It was less attracted when n-octanol and 1-nonanol concentrations decreased. [Conclusion] N. barkeri have different behavioral responses to volatile components from citrus leaves damaged by P. citri compared to those damaged by piercing-sucking insects. Chemical cues induced by the feeding activity of P. citri and piercing-sucking insects play an important role in host selection and location by N. barkeri.

Li HongJun

Papers

Primary studies of acarocidal activity of twenty plants extracts against Panonychus citri.

Selection of resistance to amitraz and analysis of expression difference of cytochrome P450 genes in Panonychus citri (Acari: Tetranychidae).

Study on prediction mathematical model of occurrence quantity and period for oriental fruit fly (Bactrocera dorsalis)

Toxicity of three fungicides to Xanthomonas axonopodis pv. citri.

Behavioral response of Neoseiulus barkeri to carrizo citrange leaves damaged by Panonychus citri and sucking insects