金龟子绿僵菌对褐飞虱若虫的毒力测定

研究了一株金龟子绿僵菌Metarhizium anisoplise Ma22菌株对褐飞虱若虫的毒力.结果表明:随着真菌孢子浓度的增加,接种后褐飞虱的逐日死亡率上升.用时间-剂量-死亡率模型对生物测定结果进行模拟分析,估计出了绿僵菌对褐飞虱的致死剂量与致死时间.褐飞虱接种真菌后第6天的LC50值为4.04×108个孢子/L;在接种剂量为1×109、1×1010个孢子/L时,LT50值分别为5.38、4.52 d.该菌株在褐飞虱的生物防治中具有很大的应用潜力.     

几种新烟碱类杀虫剂对褐飞虱的防效及用药技术研究

田间试验表明．10％烯啶虫胺AS、25％噻虫嗪WG和10％氯噻啉WP等三种新烟碱类杀虫剂防治五代褐飞虱,10％烯啶虫胺AS表现出良好的速效性和持效性,药后3～21d对褐飞虱防效分别在83．3％～100％,25％噻虫嗪WG速效性较差但持效性理想．药后3～21d对褐飞虱防效分别在55．9％～90％,10％氯噻啉WP防效不佳。对褐飞虱的防治技术进行了探讨,提出了褐飞虱的防治应贯彻“治前控后”的策略,做好药剂的交替使用,延缓褐飞虱抗药性的产生。     

三氟苯嘧啶与呋虫胺对贵州褐飞虱种群的增效作用及田间防效

为明确贵州褐飞虱田间种群对三氟苯嘧啶与呋虫胺的敏感性,采用稻苗浸渍法测定了三氟苯嘧啶、呋虫胺及两者混用组合对贵州黄平、湄潭、惠水3地褐飞虱田间种群的室内毒力.结果表明,湄潭田间褐飞虱种群对三氟苯嘧啶产生了低水平抗性,另外2个地区褐飞虱种群对三氟苯嘧啶仍处于敏感水平.黄平和惠水褐飞虱种群对呋虫胺表现为中等水平抗性,抗性倍...     

治褐飞虱要用长效内吸药

治褐飞虱,要根据褐飞虱的发生和危害特点,适期用药,并根据田间褐飞虱的发生情况选用适当的杀虫剂。     

褐飞虱抗药性及再猖獗研究进展

褐飞虱是一种重要的农业害虫，其对许多杀虫剂都产生了抗药性。对褐飞虱抗药性的形成和发展及其抗药性机理等方面进行了综述，并对该虫的再猖獗进行了探讨。     

黄山稻区单季中稻防控褐飞虱大发生技术研究

为了明确单季中稻褐飞虱大发生条件下的防控技术。通过不同药剂组合进行防治褐飞虱的田间药效试验,并进行大田示范验证。结果表明,在四(2)代低龄若虫高峰期选择对褐飞虱高效的药剂呋虫胺进行防治,并在五(3)代低龄高峰期使用呋虫胺或吡蚜酮等再进行1次防治,可以有效控制褐飞虱危害。     

25%噻虫·吡蚜酮WP防治稻飞虱田间试验研究

为明确25%噻虫·吡蚜酮WP对水稻褐飞虱及灰飞虱的防治效果,进行了小区药剂试验。结果表明:25%噻虫·吡蚜酮WP对灰飞虱和褐飞虱控制作用较好,建议在低龄若虫高峰期用药,制剂用量以180~360 g/hm2为宜。     

稻褐飞虱的抗药性研究

用毛细管点滴法测定了16种杀虫剂对褐飞虱的触杀毒力。1985～1990年,褐飞虱对同一杀虫剂的敏感度变异不大,抗药性发展缓慢。作者认为,褐飞虱在一定时间内不会出现抗药性突增的变化,氨基甲酸酯类仍可作为防治药剂,但需加强监测。     

浅谈稻飞虱的危害与防治

稻飞虱属同翅目飞虱科害虫,俗名火蠓虫,以刺吸植株汁液为害水稻等作物。常见种类有褐飞虱、白背飞虱和灰飞虱。稻飞虱是水稻上最主要害虫,其发生为害具有隐藏性、暴发性和毁灭性的特点。稻飞虱主要是指褐飞虱、白背飞虱和灰飞虱,它是一种迁飞性害虫,给水稻生产造成严重危害。     

褐飞虱抗药性逐年加重,亟需采取有效对策严加防控

正水稻褐飞虱是沿江地区中晚粳稻区水稻中后期的重要害虫,特别是三、四代褐飞虱的发生为害,严重威胁水稻的正常生长发育,导致对水稻的产量和品质大幅度下降,对水稻高产稳产和增产增收影响更大。据初步统计:2005年以来,水稻中后期褐飞虱连年中等以上至大发生,重发年份造成部分田块水稻全田枯死,给水稻生产造成很大威胁。特别是2005年因水稻褐飞虱对防治飞虱的     

Cytochrome P450 Dependent Activities in Mussel and Fish from Coastal Marine Environment: Field Studies on the French Coast of the Mediterranean Sea

Hepatic cytochrome P450 monooxygenase activities including Benzo(a)pyrene hydroxylase (BPH), biomarker of exposure to polycyclic hydrocarbons (PAH) and other organic contaminants like polychlorobiphenyls (PCB) was measured in the microsomal fraction from the fish, Serranus cabrilla (sea comber) liver, and the mussel, Mytilus galloprovincialis, digestive gland. Additionally, ethoxyresorufin-O-deethylase (EROD) activity measurements were made on the same fish samples. The animals were collected from multiple sites on the French Mediterranean coast, exhibiting various degrees of sediment contamination by urban/industrial wastes quantified in term of PAH and PCB sediment content. Mussel BPH, fish BPH and to a lower extent fish EROD activities were tentatively correlated to sediment PAH/PCB content. The presence of low concentration (20 μM) of α-naphthoflavone (ANF) in the assay mixture increased hepatic BPH activity of sea comber. Statistical correlation of hepatic BPH with PAH level in sediment was greater with the presence of ANF. This work demonstrates the potential of mussel to be used in biomonitoring programmes for coastal pollution survey.     

Bio-Efficacy of Chrysoeriol7, a Natural Chemical and Repellent,against Brown Planthopper in Rice

Brown planthopper (BPH, Nilaparvata lugens Stal.) is the most damaging rice pest affecting stable rice yields worldwide. Currently, methods for controlling BPH include breeding a BPH-resistant cultivar and using synthetic pesticides. Nevertheless, the continuous cultivation of resistant cultivars allows for the emergence of various resistant races, and the use of synthetic pesticides can induce environmental pollution as well as the emergence of unpredictable new pest species. As plants cannot migrate to other locations on their own to combat various stresses, the production of secondary metabolites allows plants to protect themselves from stress and tolerate their reproduction. Pesticides using natural products are currently being developed to prevent environmental pollution and ecosystem disturbance caused by synthetic pesticides. In this study, after BPH infection in rice, chrysoeriol7 (C7), a secondary metabolite that induces resistance against BPH, was assessed. After C7 treatment and BPH infection, relative expression levels of the flavonoid-related genes were elevated, suggesting that in plants subjected to BPH, compounds related to flavonoids, among the secondary metabolites, play an important role in inducing resistance. The plant-derived natural compound chrysoeriol7 can potentially thus be used to develop environmentally friendly pesticides. The suggested control of BPH can be effectively used to alleviate concerns regarding environmental pollution and to construct a relatively safe rice breeding environment.     

LILRA3 Is Associated with Benign Prostatic Hyperplasia Risk in a Chinese Population

A recent prostate cancer (PCa) genome-wide association study (GWAS) identified rs103294, a single nucleotide polymorphism (SNP) located on LILRA3, a key component in the regulation of inflammatory inhibition, to be significantly associated with PCa risk in a Chinese population. Because inflammation may be a common etiological risk factor between PCa and benign prostatic hyperplasia (BPH), the current study was conducted to investigate the association of rs103294 with BPH risk. rs103294 was genotyped in a Chinese population of 426 BPH cases and 1,008 controls from Xinhua Hospital in Shanghai, China. Association between rs103294, BPH risk and clinicopathological traits were tested with adjustment for age. rs103294 was significantly associated with BPH risk with a p-value of 0.0067. Individuals with risk allele “C” had increased risk for BPH (OR = 1.34, 95% CI: 1.09–1.66). Stratified analysis revealed a stronger association risk for younger patients who are below 72 years old (OR = 1.51, 95% CI: 1.06–2.16). Our study represents the first effort to demonstrate that LILRA3 gene is significantly associated with BPH risk in a Chinese population. Our results support a common role of inflammation in the development of PCa and BPH. Additional studies are needed to further evaluate our results.     

Diversity in steroidogenesis of symbiotic microorganisms from planthoppers

Ergosta-5,7,24(28)-trien-3-ol (trienol)6 was isolated from the intracellular symbiotes (symbiotic microorganisms) of the planthoppers,Nilaparvata lugens andLaodelphax striatellus. The steroidogenic end product of the symbiotes was found to depend on the environmental conditions, i.e., although trienol6 was produced under symbiotic conditions, ergosterol4 was formed in aerobic culture. When the normal diet was replaced by a steroiddeficient artificial one, the ratio of 24-methylenecholesterol5 to total insect sterols was significantly increased. The above study offers further corroborating evidence for our assumption that the host insects require 24-methylenecholesterol5 as an alternate source for cholesterol1 under certain environmental conditions. In our previous biotransformation experiments, 24methylenecholesterol5 was shown to be an immediate precursor of cholesterol1. However, the complexity of the insects' vital functions hindered all subsequent attempted transformations into cholesterol1 of sitosterol2, trienol6, and ergosterol4, under injection conditions.     

Overexpression of an Osa-miR162a Derivative in Rice Confers Cross-Kingdom RNA Interference-Mediated Brown Planthopper Resistance without Perturbing Host Development

Rice is a main food crop for more than half of the global population. The brown planthopper (BPH, Nilaparvata lugens) is one of the most destructive insect pests of rice. Currently, repeated overuse of chemical insecticides represents a common practice in agriculture for BPH control, which can induce insect tolerance and provoke environmental concerns. This situation calls for innovative and widely applicable strategies for rice protection against BPH. Here we report that the rice osa-miR162a can mediate cross-kingdom RNA interference (RNAi) by targeting the NlTOR (Target of rapamycin) gene of BPH that regulates the reproduction process. Through artificial diet or injection, osa-miR162a mimics repressed the NlTOR expression and impaired the oviposition of BPH adults. Consistently, overproduced osa-miR162a in transgenic rice plants compromised the fecundity of BPH adults fed with these plants, but meanwhile perturbed root and grain development. To circumvent this issue, we generated osa-miR162a-m1, a sequence-optimized osa-miR162a, by decreasing base complementarity to rice endogenous target genes while increasing base complementarity to NlTOR. Transgenic overexpression of osa-miR162a-m1 conferred rice resistance to BPH without detectable developmental penalty. This work reveals the first cross-kingdom RNAi mechanism in rice-BPH interactions and inspires a potentially useful approach for improving rice resistance to BPH. We also introduce an effective strategy to uncouple unwanted host developmental perturbation from desirable cross-kingdom RNAi benefits for overexpressed plant miRNAs.     

Silencing an E3 Ubiquitin Ligase Gene OsJMJ715 Enhances the Resistance of Rice to a Piercing-Sucking Herbivore by Activating ABA and JA Signaling Pathways

The RING-type E3 ubiquitin ligases play an important role in plant growth, development, and defense responses to abiotic stresses and pathogens. However, their roles in the resistance of plants to herbivorous insects remain largely unknown. In this study, we isolated the rice gene OsJMJ715, which encodes a RING-domain containing protein, and investigated its role in rice resistance to brown planthopper (BPH, Nilaparvata lugens). OsJMJ715 is a nucleus-localized E3 ligase whose mRNA levels were upregulated by the infestation of gravid BPH females, mechanical wounding, and treatment with JA or ABA. Silencing OsJMJ715 enhanced BPH-elicited levels of ABA, JA, and JA-Ile as well as the amount of callose deposition in plants, which in turn increased the resistance of rice to BPH by reducing the feeding of BPH and the hatching rate of BPH eggs. These findings suggest that OsJMJ715 negative regulates the BPH-induced biosynthesis of ABA, JA, and JA-Ile and that BPH benefits by enhancing the expression of OsJMJ715.