Assessment of Brown Planthopper, (Nilaparvata lugens) [Stål], damage in rice using hyperspectral remote sensing

Hyperspectral remote sensing was used to detect stress on potted rice plants caused by the Brown Planthopper (BPH), Nilaparvata lugens (Stål). BPH damage influenced reflectance of rice plants compared to uninfested plants in the visible and near-infrared regions of the electromagnetic spectrum. Correlations between plant reflectance and BPH damage, when plotted against wavelengths, enabled us to identify four sensitive wavelengths, at 1986, 665, 1792 and 500 nm, in relation to BPH stress on rice plants. Based on rice plant reflectance corresponding to the sensitive wavelengths, three hyperspectral indices were developed. The BPH damage showed a positive association with normalized pigment chlorophyll index, and a negative relationship with normalized difference vegetation index and soil adjusted vegetation index. Using rice plant reflectance corresponding to the sensitive wavelengths, a multiple-linear regression model was developed and validated, which would facilitate assessment of BPH damage based on rice plant reflectance, thereby ensuring prompt forewarning to stakeholders.     

Early assessment of the yield loss in rice due to the brown planthopper using a hyperspectral remote sensing method

The brown planthopper (BPH) is an important pest in rice. Rice losses due to BPH's damage are often more than 10% of yield. Assessments on loss rates from BPH are now basically dependent on experiential indices. However, early assessments on rice yield losses using hyperspectral data are still rare. In this study, reflectance from rice canopy was measured in net cages after different densities of BPH release. Results showed that reflectance in the near-infrared region (750–1000 nm) from milk grain stage, and in 400–531 nm and 567–705 nm from mature grain stage was closely related to BPH density. These spectral indices: red-edge parameters (λ_r, Dλ_r, Sλ_r), ratio of the maximal reflectance in green (490–560 nm) to minimal reflectance (640–740 nm) in red (R_GREEN/R_RED), ratio of the near-infrared peak (R_NIR) to R_RED, normalized difference vegetation index between R_NIR and R_RED and soil-adjusted vegetation index (SAVI) from both milk and mature grain stages, indicated BPH densities well. As expected, rate of loss in rice grain was higher with increasing BPH density. SAVI, Dλ_r, Sλ_r and reflectance at 760 nm (R₇₆₀) from milk grain stage were significantly correlated with rates of loss in panicle, and 1000-grain weight and multiple-linear regression models for detecting loss rate were established. The hyperspectral reflectance from rice at milk grain stage can be used to assess rice yield losses due to BPH and improve management policies.     

我国主要稻区褐稻虱生物型的研究

采用具有不同抗性基因的水稻品种,测定了我国主要水稻区包括9个省25个县市的褐稻虱,除TN1品种属敏感外,其他品种均表现出抗性。说明这些地区的褐稻虱属于生物型1。从生存率和群体建立试验结果来看,也证实了上述的结果。根据褐稻虱在我国稻区以生物型1为主的事实,本文对今后抗褐稻虱水稻品种选育的策略进行了讨论。     

沉默转录因子OsERF7提高水稻对褐飞虱和白背飞虱的抗性

为了解植物中特有的转录因子乙烯响应因子(ethylene responsive factor,ERF)在植物诱导抗虫反应中的作用,通过克隆1个水稻ERF转录因子基因OsERF7,并结合分子生物学、反向遗传学及生物测定,探究其在水稻防御褐飞虱Nilaparvata lugens和白背飞虱Sogatella furcifera为害过程中的作用。结果显示,机械损伤处理与褐飞虱产卵雌成虫为害均能在中后期诱导OsERF7的表达。沉默OsERF7能显著降低水稻上褐飞虱及白背飞虱卵的孵化率,并延长褐飞虱卵的发育历期;与野生型水稻相比,褐飞虱和白背飞虱在沉默突变体品系R1和R30上的卵孵化率分别只有野生型水稻上的62.5%～68.3%和68.0%～76.0%,褐飞虱卵的发育历期则延长0.37～0.45 d。沉默OsERF7不影响褐飞虱产卵雌成虫为害诱导的水稻防御相关信号分子—茉莉酸(JA)、水杨酸(SA)、乙烯(ET)和过氧化氢(H_2O_2)的含量。表明转录因子OsERF7作用于防御相关信号途径的下游,并且负调控水稻对褐飞虱和白背飞虱的抗性。     

嘉兴粳稻抗褐稻虱育种籼稻抗源的选择和利用

用嘉兴田间采集的褐稻虱对籼型扰虫品种BG367-4进行苗期和成株期抗性鉴定,均表现为高抗(HR)。用作粳稻抗褐稻虱育种的抗性授体亲本,抗性传递力强,并表现为显性遗传,是籼粳杂交培育粳型抗虫品种的理想抗源。     

Effects of herbicides on rice resistance and on multiplication and feeding of brown planthopper (BPH), Nilaparvata lugens (StÅl) (Homoptera: Delphacidae)

Two-way effects of herbicide on rice resistance and multiplication and feeding of the rice brown planthopper (BPH), Nilaparvata lugens (Stål) were studied. Four of 11 herbicides tested, butachlor, metolachlor, oxadiazon and bentazone, had significantly stimulating effects on multiplication and feeding of BPH. Multiplication times (N ₁/N ₀) of BPH on the rice treated with the four herbicides were 674, 367, 322 and 311, respectively, while that of N. lugens on the untreated plants was 159. The results of measurements of honeydew production by BPH indicated that the feeding rates of the brown planthoppers increased when the insects fed on the plants treated with bentazone, quinclorac, oxadiazon and quinclorac. Survival rates of N. lugens first to third-instars rose on the rice plants treated with butachlor, bentazone, but that of the fourth and fifth instars were not affected. Furthermore, all of those herbicides tested led to a decline of rice resistance, i.e. the injury scales of the treated plants were larger than that of the control under the same pest stress. Based on their effects on rice resistance and on BPH, the herbicides tested can be divided into two categories, one affecting rice resistance and BPH multiplication, the other affecting rice resistance only.     

Possible connection between imidacloprid-induced changes in rice gene transcription profiles and susceptibility to the brown plant hopper Nilaparvatalugens Stål (Hemiptera: Delphacidae)

The chemical pesticide, imidacloprid (IMI) has long-lasting effectiveness against Hemiptera. IMI is commonly used to control the brown planthopper (BPH), Nilaparvata lugens Stål (Hemiptera: Delphacidae). Some chemical pesticides, however, can induce the susceptibility of rice to BPH, which has indirectly led to the resurgence of BPH. The mechanism of the chemical induction of the susceptibility of rice to BPH was not previously understood. Here, a 44 K Agilent Rice Expression Microarray was used to identify changes in gene expression that accompany IMI-induced rice susceptibility to BPH. The results showed that 225 genes were differentially expressed, of which 117 were upregulated, and 108 were downregulated. Gene ontology annotation and pathway analysis revealed that differentially expressed genes were mainly classified into the eight functional groups: oxidation reduction, regulation of cellular process, response to stress, electron carrier activity, metabolic process, transport, signal transducer, and organismal development. The genes encoding plant lipid transfer protein, lignin peroxidase, and flavonol-3-O-methyltransferenase may be important responses to the IMI-induced susceptibility of rice to BPH. The reliability of the microarray data was verified by performing quantitative real-time PCR and the data provide valuable information for further study of the molecular mechanism of IMI-induced susceptibility of rice.     

Decrease of rice plant resistance and induction of hormesis and carboxylesterase titre in brown planthopper, Nilaparvata lugens (Stål) by xenobiotics

The brown planthopper (BPH), Nilaparvata lugens (Stål) is a serious threat to the rice production throughout Asia. The indiscriminate application of various xenobiotics in rice ecosystem is perceived as one of the factors for the frequent outbreak of BPH. The present study has critically analysed the secondary effects of some xenobiotics used in rice field on certain plant and insect parameters that subsequently favour BPH outbreak. Application of 2,4-D, carbendazim, deltamethrin and urea reduced the innate BPH resistance of PTB 33 rice variety due to favourable alterations in rice free amino acid and sucrose content. Similarly, these chemicals also induced hormesis and enhanced feeding in BPH. Alternatively, soil amendment with neem seed powder and Calotropis gigantea leaves improved plant innate resistance and showed no sign of hormesis or enhanced feeding in BPH. In addition, deltamethrin has the ability to stimulate BPH carboxylesterase titre. Native PAGE analysis of esterases from whole body homogenate of BPH revealed at least five esterase isozyme bands, prominent being E1 and E2. However, no difference in BPH esterase banding pattern was observed between different xenobiotic treatments. All these esterase bands are classified under carboxylesterase based on their inhibition by class specific esterase inhibitors.     

褐飞虱及白背飞虱空中迁飞规律的研究

为了研究褐飞虱、白背飞虱的迁飞规律,作者于1977～1979年夏季和秋季,在华中地区,用运五型飞机,携带自行设计的活动型捕虫装置,进行空中捕捉褐飞虱、白背飞虱的试验。三年间共飞行91小时58分,计13000公里,共捕获褐飞虱、白背飞虱1915头,占捕虫总数的53.71%。试验结果证实了这两虫具有明显的季节性的中、长距离的迁飞特性,并探明了其空中迁飞的垂直高度、水平分布、虫口密度和迁飞种群的型式、姿态、生理状况、回迁动态以及迁飞起飞与气象条件的关系。     

杂交稻对褐稻虱和白背飞虱的抗性研究

本研究对我国南方稻区的38个杂交稻组合进行了对褐稻虱和白背飞虱的抗性测定,结果有9个组合兼抗褐稻虱和白背飞虱,仅抗其中1种飞虱的各占6个。采用经过改进的生存率及蜜露测定法,研究了杂交稻组合对两种飞虱的抗性机制,证明:杂交稻多数组合对白背飞虱的抗性机制以耐害性为主,其中部分组合兼有一定程度的抗生性;而对褐稻虱的抗性机制,多数组合表现以抗生性为主。对白背飞虱在某些地区推广杂交稻后上升为主要害虫的原因也作了探讨。     

抗褐飞虱兼抗白背飞虱水稻种质资源发掘

为了发掘出对褐飞虱生物型Ⅱ、孟加拉型及白背飞虱具有抗性的稻种资源供抗褐飞虱兼抗白背飞虱育种选用,采用苗期群体鉴定法对383份水稻种质资源进行了抗性鉴定。发掘出107份抗褐飞虱兼抗白背飞虱的稻种资源。其中,抗褐飞虱生物型Ⅱ兼抗白背飞虱的稻种资源58份,占抗性鉴定总数的15.14%;抗褐飞虱孟加拉型兼抗白背飞虱的稻种资源49份,占抗性鉴定总数的12.79%。本研究发掘的107份抗褐飞虱兼抗白背飞虱的稻种资源,在育种时可作为亲本选用。     

Effect of fenvalerate on the reproduction and fitness costs of the brown planthopper, Nilaparvata lugens and its resistance mechanism

The brown planthopper (BPH), Nilaparvata lugens Stål, is a primary insect pest of cultivated rice, and its effective control is essential for crop production. However, in recent years, outbreaks of the brown planthopper have occurred more frequently in China. In order to determine the causes and mechanisms of insecticide-induced BPH resurgence and perform population management, we conducted the following studies. By the topical application method, our results showed that, fenvalerate acted as stimulus of fecundity from 3.50 × 10⁻³ to 2.02 × 10⁻² μg/female in the BPH. Apart from 7.00 × 10⁻³ μg/female, the number of hatched nymphs was increased gradually with an increase in application dose from 3.50 × 10⁻³ to 1.74 × 10⁻² μg/female. After continuous selection with fenvalerate for 11 generations by the rice-stem dipping method, a resistant strain was achieved with medium resistance to fenvalerate (RR 39.22). Life table study indicated that the resistant strain (G4 and G8) showed reproductive advantages, including increased female ratio, copulation rate and fecundity. But the hatchability of resistant strain was lower. The survival rate and emergence rate were significantly lower in G4 and G8 resistant strain. Resistant strains in G4 and G8 showed a fitness advantage (1.04 and 1.11), and the number of offspring in G8 generation was higher than that in G4 generation. The significant difference detected between resistant insects (G4, G5, G8 and G9) and S-strain contains not only the effect of resistant selection but also the effect of continuous rearing itself. Hence it was concluded that the BPH had the potential to develop high resistance against fenvalerate and the induction of the nymphs by sublethal doses of fenvalerate was of importance in the BPH population management, particularly in the predicting. Further studies demonstrated that triphenyl phosphate (TPP) and diethyl maleate (DEM) had no synergism on fenvalerate. However, piperonyl butoxide (PBO) displayed significant synergism in susceptible strain (1.97) and resistant strain (2.73). We concluded that esterase and glutathione S-transferase play little role in fenvalerate detoxification. The increase of the P450-monooxygenases detoxification is an important mechanism for fenvalerate resistance. Because their resistant populations had a fitness advantage, we should pay close attention to the occurrence of BPH and use other functionally different insecticides to control the BPH.     

褐飞虱对吡虫啉、噻嗪酮和氟虫腈的抗性监测

2005年10月至2007年10月,用稻茎浸渍法测定12个褐飞虱种群对吡虫啉、噻嗪酮和氟虫腈的敏感性。结果表明：12个褐飞虱种群对吡虫啉均达高或极高水平抗性;除2005年南宁、韶关和阳江,2006年阳江及2007年永州5个褐飞虱种群对噻嗪酮仍处于敏感水平外,其余种群处于敏感性降低或达到低水平抗性;而2006年阳江褐飞虱种群对氟虫腈处于敏感性降低阶段,其余的8个种群均达到了低或中等水平抗性。     

2005年长江流域稻区褐飞虱暴发成灾原因分析

从害虫种群动态的基本原理出发,通过历史资料的比较分析,研究了导致2005年褐飞虱暴发成灾的关键因子。结果认为一定的迁入虫量为褐飞虱暴发成灾奠定了基础,异常高的种群增长倍数是暴发的关键,而引起高种群增长倍数的主要因子是单季稻面积的扩大,异常的气候条件和滥用化学农药。长期过量施用吡虫啉而引起的抗药性和失时防治带来的低防治效果,导致了严重的灾害。2005年褐飞虱暴发成灾的重要启示是:褐飞虱治理的关键在于通过减少前期不合理的农药施用,改良品种的遗传性状和促进田间自然控制作用,建立起一个能有效控制褐飞虱高增长能力的生态系统。     

褐稻虱为害损失测算方法的研究

进行盆栽单株罩笼接虫试验,测定褐稻虱三龄若虫在水稻分蘖末、孕穗和乳熟期,一龄若虫和成虫在孕穗期为害15天所造成的产量损失。根据褐稻虱的发育历期及其与累计取食量的关系,推算出每头褐稻虱在各虫龄期内的平均为害损失,由此推导出不同虫龄若虫和成虫的逐日为害损失率模型。探讨了一种较为准确的褐稻虱为害损失的测算方法。     

水稻品种抗性对虫体酯酶的影响

采用苗期群体鉴定法对供试水稻品种进行了抗性鉴定,在此基础上测定了取食不同抗性水稻品种的褐稻虱(Nilaparvata lugens)羧酸醑酶、酸性及碱性磷酸酯酶活力的变化。结果表明,取食感虫品种的褐稻虱若虫及第2代若虫体内上述三种酶的活力明显高于取食抗虫品种的;取食中抗品种的褐稻虱若虫三种酶的活力介于取食感虫和抗虫品种的若虫之间。这一结果与褐稻虱在不同抗性水平上水稻品种的存活率和发育进度是一致的。表明抗虫品种对褐稻虱具有抗生机制,从而抑制了虫体的正常生长发育。取食不同水稻品种的褐稻虱的羧酸酯酶米氏常数(Km)值无明显差异,但最大反应速度(Vmax)值差异极显著。取食感虫品种的 Vmax 值明显高于取食抗虫品种的。这表明取食不同抗性水稻品种的褐稻虱羧酸酯酶性质相同,差异主要是由于酶量的不同。     

褐飞虱生物型的分子生物学研究进展

综述了国内外有关褐飞虱生物型分子生物学研究的最新进展,内容包括褐飞虱生物型的分子多态型、生物 型发生与转化的分子基础、生物型与抗性、生物型与共生菌之间的关系等。     

多抗性晚籼浙丽1号(6202)对几种主要病虫的抗性

作者等自1973年开始进行抗病虫水稻品种的研究工作,现已育成抗主要病虫害:褐飞虱、自背飞虱、黑尾叶蝉和稻瘟病的晚籼浙丽1号(6202)。组合为广塘矮/Mudgo//竹科2号。本文还就耕作制度尤其抗虫品种以及褐飞虱“生物型”与稻飞虱种群动态的关系进行了讨论,并查明当地褐飞虱田间优势种群目前尚属生物型1。     

褐飞虱与白背飞虱为害诱导水稻防御反应的比较

为探究2种稻飞虱——褐飞虱Nilaparvata lugens(St?l)和白背飞虱Sogatella furcifera(Horváth)诱导的水稻防御反应差异,于室内测定了水稻在分别受褐飞虱或白背飞虱产卵雌成虫为害时,其茉莉酸、水杨酸、乙烯、H_2O_2以及挥发物含量的变化。结果表明,尽管褐飞虱和白背飞虱产卵雌成虫的为害均可以诱导水稻茉莉酸、水杨酸、乙烯和H_2O_2等防御相关信号分子以及一些水稻挥发物含量的增加,但是二者的诱导作用存在差异。水稻在受白背飞虱产卵雌成虫为害时,茉莉酸的含量在3 h时就显著升高,12 h时含量达到最高;而受褐飞虱产卵雌成虫为害时,6 h时茉莉酸含量才显著升高,72 h时含量达最高;并且在2种稻飞虱为害的3～48 h内,白背飞虱为害诱导的茉莉酸含量始终显著高于褐飞虱为害诱导的。水稻受白背飞虱产卵雌成虫为害24 h后诱导的水杨酸含量、为害48 h后诱导的乙烯含量、为害72 h后诱导的H_2O_2含量及为害24 h后诱导的挥发物释放量分别是褐飞虱产卵雌成虫为害诱导的1.28、1.45、4.10和1.77倍。表明水稻能识别褐飞虱和白背飞虱的为害,从而做出针对害虫种类特异性的防御反应;并且水稻对白背飞虱产卵雌成虫为害所做出的防御反应比对褐飞虱的更强烈。     

Species-specific insecticide resistance to imidacloprid and fipronil in the rice planthoppers Nilaparvata lugens and Sogatella furcifera in East and South-east Asia

BACKGROUND: In 2003 the development of insecticide resistance against neonicotinoids in the brown planthopper (BPH), Nilaparvata lugens (Stål) (Homoptera: Delphacidae), was first observed in Thailand and has since been found in other Asian countries such as Vietnam, China and Japan. However, the LD₅₀ values of BPH and the whitebacked planthopper (WBPH), Sogatella furcifera (Horváth), against both neonicotinoid and phenylpyrazole insecticides have been poorly reported in many Asian countries. RESULTS: The topical LD₅₀ values for imidacloprid in the BPH populations collected from East Asia (Japan, China, Taiwan) and Vietnam in 2006 were 4.3–24.2 µg g^?1 and were significantly higher than those collected from the Philippines (0.18–0.35 µg g^?1). The BPH populations indicated a positive cross‐resistance between imidacloprid and thiamethoxam. Almost all the WBPH populations from Japan, Taiwan, China, Vietnam and the Philippines had extremely large LD₅₀ values (19.7–239 µg g^?1 or more) for fipronil, except for several populations from the Philippines and China. CONCLUSION: Species‐specific changes in insecticide susceptibility were found in Asian rice planthoppers (i.e. BPH for imidacloprid and WBPH for fipronil). Insecticide resistance in BPH against imidacloprid occurred in East Asia and Indochina, but not in the Philippines. In contrast, insecticide resistance in WBPH against fipronil occurred widely in East and South‐east Asia. Copyright © 2008 Society of Chemical Industry