柑桔潜叶蛾自然种群生命表的组建及分析

将柑桔潜叶蛾种群按其生长发育顺序划分为卵（Ｅ）、１龄幼虫（Ｌ１）、２龄幼虫（Ｌ２）、３龄幼虫（Ｌ３）、４龄幼虫（Ｌ４）、蛹（Ｐ）、成虫（Ａ）７个阶段,把各阶段的作用因子划分为相对独立的状态．根据田间调查及室内实验观察,记录各阶段的存活数,综合Ｂｅｒｙｍａｎ和宫下的方法,推算出各阶段各因子作用下的存活率,缩小了世代重叠给自种群生命表带来的误差,组建了柑桔潜叶蛾第９世代的自然种群生命表,得出其种群趋势指数为１．３２,重要因子分析表明,影响柑桔潜叶蛾自然种群的重要因子是寄生性天敌．     

柑桔潜叶蛾对柑桔的为害及经济阈值的研究

调查福州市郊柑桔园柑桔潜叶蛾（Ｐｈｙｌｏｃｎｉｓｔｉｓｃｉｔｒｅｌａ）在雪柑、芦柑、蕉柑、福桔４个品种上的为害情况．根据其为害特性和柑桔果实产量大小年份可能给经济阈值带来的误差,采用同一树上以秋梢为计量单位,环割被测枝条（避免枝条间养分重新分配而带来误差）的方法,研究了为害秋梢的叶片光合作用强度,当年和翌年春夏梢的生长量,翌年果实品质和重量,以及叶片被害程度与柑桔潜叶蛾幼虫密度的关系．结果表明,柑桔受潜叶蛾为害后具有一定的光合补偿及组织愈伤的补偿能力;根据福州地区１９９４年柑桔生产力,以雪柑为品种确定经济阈值为１．２１头１龄幼虫／嫩叶;缩小了经济阈值受果实产量大小年份差异而带来的误差;同时考虑品种、柑桔园水热条件、产量水平、天敌作用等多种生态因子,建立了多因子经济阈值模型     

Factors influencing adult female oviposition in the citrus leafminer Phyllocnistis citrella

1 The citrus leafminer (CLM) Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) is a serious pest in most citrus‐growing regions of the world. The influence of leaf length, citrus species or variety, leaf colour tone and temperature on CLM oviposition was studied from field observations and laboratory experiments. The spatial distribution of eggs on leaves was also examined. Field data were obtained from 1100 samples collected in eastern Spain for 7 years. 2 Significant differences in oviposition rate were found among citrus species in ‘no choice’ laboratory experiments. This tendency was not apparent in the field due to the confounding effect of such factors as the intensity of new flushes and adult CLM abundance. Leaf colour tone and air temperature in the range studied (18–27°C) had no effect on CLM egg‐laying. 3 The distribution of eggs among leaves was random for population densities lower than four eggs per leaf, but became strongly aggregated above this, when not all eggs could survive and complete development. 4 The CLM developmental stage found on leaves depended on the leaf length, and most of the egg‐laying occurred only on leaves that were 10–25 mm long. These leaves had the highest CLM stages in the field and thus give the best estimate of CLM oviposition.     

Efficacy and uptake of soil-applied imidacloprid in the control of Asian citrus psyllid and a citrus leafminer, two foliar-feeding citrus pests

The systemic neonicotinoid insecticide imidacloprid, Admire Pro, was applied to 3- and 4-yr-old nonbearing 'Rio Red' grapefruit, Citrus x paradisi Macfad., trees in 2006 and 2007, respectively, to determine its effects in the control of two major citrus pests, the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), and a citrus leafminer Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae). Young flush shoots were randomly collected weekly for 13 and 11 wk in 2006 and 2007, respectively, to determine the infestation levels and densities of immature stages of both Asian citrus psyllid and P. citrella. Additional flush shoot samples were collected in 2007 and titers of imidacloprid in leaf tissue were determined using an enzyme-linked immunosorbent assay. Soil application of imidacloprid significantly reduced the infestation levels and densities of both pests on flush shoots, starting from the second week post application. The effects of the neonicotinoid insecticide were similar in both years. Analysis of imidacloprid concentration in leaf tissue showed a gradual increase during the first 3 wk, and titers remained well above 200 ppb for 11 wk postapplication. Significant positive correlations were obtained between imidacloprid titers in leaf tissue and the percentage of control levels achieved for both pests. A high level of suppression of both P. citrella and Asian citrus psyllid populations on citrus trees was associated with imidacloprid titer in leaf tissue >200 ppb, which was reached 2 wk after soil treatment. Although soil application of imidacloprid did not provide rapid knockdown of Asian citrus psyllid and P. citrella populations, it resulted in chronic residues in leaf tissue and long-term suppression of both pests.     

Parasitoid complex of citrus leafminer, Phyllocnistis citrellaon lemon in the Central Jordan Valley

From March 1997 to June 1999, samples of lemonleaves infested with citrus leafminer (CLM),Phyllocnistis citrella Stainton(Lepidoptera: Gracillariidae), were collectedfrom the Al-Masalha Citrus Orchard in theCentral Jordan Valley in order to rear CLMparasitoids and to study their populationtrends. Nine species of eulophid parasitoidswere reared from CLM larvae; these were Cirrospilus ingenuus Gahan, C. pictusNees, Pnigalio agraules, Pnigalio sp. B,Pnigalio sp. C, Citrostichusphyllocnistoides Narayanan, Ratzeburgiolaincompleata Boucek, Semielacherpetiolatus Girault, and Zagrammosoma sp.Cirrospilus ingenuus was the most commonparasitoid of CLM from March 1997 to June 1999and could be a good potential biologicalcontrol agent after rearing and releasing it incitrus orchards in the Jordan Valley. Onehyperparasitoid species was reared fromimmatures of parasitoids of CLM larvae, andidentified as Tyndrichus sp. An increasein the activity of parasitoids was observed inautumn 1999 when the temperature was between 15–20 °C and the relative humidity was between 55–65%.     

Factors affecting captures of male citrus leafminer, Phyllocnistis citrella Stainton, in pheromone-baited traps

The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), is an important world‐wide pest of citrus. Larval mining within leaf flush impacts yield and predisposes trees to infection by citrus canker, Xanthomonas axonopodis pv. citri. The present series of studies sought to identify factors affecting male P. citrella catch in pheromone‐baited traps with the intent of developing effective monitoring. A commercially available pheromone lure (Citralure, ISCA Technologies, Riverside, CA, USA) was highly effective in attracting male P. citrella to traps. Pherocon VI Delta (Trécé Inc., Adair, OK, USA) traps baited with a Citralure captured more male P. citrella than identically baited Pherocon IC Wing traps (Trécé Inc.). The superiority of the Delta‐style trap was found to be due to a 3 cm long closing latch that likely prevents males from flying directly through the trap without capture. Within canopies of mature citrus trees (approximately 3.5 m high), traps at mid‐canopy height (2.0 m) captured more males than traps placed higher (3.5 m) or lower (0.6 m). On the canopy perimeter and in between canopies, traps near ground level (0.6 m height) captured more males than traps at 2.0 and 3.5 m heights. Male catch was greater within the tree canopy or on the canopy perimeter than 2.0 away from the canopy. Traps deployed in trees on the edge of groves captured more males than traps placed 120 and 240 m away from the grove edge and within the grove interior. In non‐pheromone‐treated grove plots, the optimal dosage for catching males was between 0.1 and 1.0 mg of the 3 : 1 blend of (Z,Z,E)‐7,11,13‐hexadecatrienal and (Z,Z)‐7,11‐hexadecadienal; however, in pheromone‐treated plots a higher 10.0 mg dosage lure was most effective. Male catch in pheromone‐baited traps exhibited a diel rhythm with most males captured during scotophase (22:00–23:00 h) and no males captured during photophase.     

Genetic analysis of susceptibility to isoniazid-induced seizures in mice

Four sets of recombinant inbred lines of mice have been used to analyze genetic differences in acute toxicity of the drug, isonicotinic acid hydrazide. Standard inbred strains, their F₁ hybrids and recombinant inbred strains were all challenged with a single dose of the drug. The percent mortality of the different groups was analyzed to estimate heritability and the number of genes affecting resistance. The data indicated that resistance factors were dominant, heritability was moderate (.25-.37), and more than one gene was involved in each of four different sets of recombinant inbred lines. Possible approaches for identifying and mapping individual genes affecting resistance are discussed.     

Toxicity of pesticides to the citrus leafminer and its parasitoid Ageniaspis citricola evaluated to assess their suitability for an IPM program in citrus nurseries

The relative toxicity of pesticides to Phyllocnistis citrella and its parasitoid Ageniaspis citricola was compared by several bioassay methods. A clip-cage bioassay measured survival of adults exposed to fresh residues at 0.25-times (0.25×), 0.5×, 1×, and 2× the lowest recommended rate of each pesticide, a water control (0×), and 24- and 48-h aged residues of oil at 1.5% (1×) rate. A one-species cylinder bioassay determined the effects of pesticides on immature stages of the citrus leafminer after treating young citrus trees with the same rates of pesticides (except for avermectin, tested at 0×, 0.01×, 0.025×, 0.05×, 0.1×, and 0.25× rates). A sublethal rate of petroleum oil (0.4%) was added as an adjuvant in some treatments. The effect of pesticides on immature stages of A. citricola was determined with a two-species cylinder bioassay after treating young citrus trees with the same rates as above. An index of IPM compatibility was developed based on the efficacy of the pesticide as a control agent of the leafminer (or other pests) and its selectivity to the parasitoid at the lowest recommended field rate (0.25× the field rate for avermectin). Azadirachtin (Neemix) + oil, diflubenzuron (Micromite) + oil, fenoxycarb (Eclipse) + oil, and oil alone (FC 435-66) were classified as IPM-compatible insecticides. Sprays of azadirachtin (Align) + oil, neem oil (Neemgard), and drenched imidacloprid (Admire) were ranked as a semi-compatible insecticides. The fungicide copper hydroxide (Kocide 101) and a fish oil-based foliar fertilizer (Zapata HFE) were considered compatible. Avermectin (Agri-Mek) + oil, ethion (Ethion), and imidacloprid (Provado) applied as a spray were IPM-incompatible insecticides. These products should be tested under field conditions to confirm these ratings.     

Genetic analysis of the susceptibility of mouse cytomegalovirus to acyclovir.

Eight independently derived mouse cytomegalovirus (MCMV) mutants resistant to acyclovir (ACV) were obtained by the sequential plating of wild-type virus in increasing concentrations of ACV. Results of complementation studies among these eight mutants suggest that all had mutations within the same or closely associated genes. A ninth MCMV mutant resistant to phosphonoacetate (PAA) derived by plating wild-type virus in the presence of 100 micrograms of PAA per ml displayed coresistance to ACV and was unable to complement any of the ACV-derived mutants. Recombination experiments among all combinations of the nine MCMV mutants were performed and supported the complementation data in that no recombination could be detected. Seven of the eight ACV-resistant mutants demonstrated cross-resistance to PAA and hypersensitivity to aphidicolin. The one mutant not coresistant to PAA was more susceptible to PAA than was the parent virus. Only a few mutants demonstrated coresistance when the mutants were tested against 9-beta-D-arabinofuranosyladenine (ara-A). The ACV mutant that demonstrated increased susceptibility to PAA was 30-fold more susceptible to ara-A but remained unchanged in susceptibility to aphidicolin. Two of the parent-mutant combinations were selected for DNA synthesis analysis in the presence of ACV (5 microM). A significant decrease in DNA synthesis was demonstrated for both parent viruses, and there was little effect on mutant virus DNA synthesis at the same drug concentration. These results suggest that susceptibility of MCMV to ACV is confined to a product of a single gene and that a mutation of this gene can lead to an altered phenotype when compared with parent virus in susceptibility of DNA synthesis to PAA, ara-A, and aphidicolin, drugs that are known to inhibit DNA polymerase activity.     

Natural mortality factors acting on citrus leafminer, Phyllocnistis citrella, in lime orchards in South Florida

Seasonal mortality of the citrusleafminer, Phyllocnistis citrellaStainton, was studied from 1994 through 1998 in`Tahiti' lime, Citrus aurantifolia (Christm.) Swingle,in Homestead, Florida. Survival of eachdevelopmental host stage and the proportionattacked by indigenous and introduced naturalenemies were determined. Before the recovery ofthe introduced parasitoid, Ageniaspiscitricola Logvinovskaya, in 1995, thethird-instar host had the highest averageproportion of parasitized individuals (0.14)followed by the prepupa (0.11) while the firstinstar had the lowest proportion parasitized(0.02). After the first recovery andestablishment of A. citricola, theproportion of pupae parasitized increased to0.56 followed by the prepupa (0.14) and thethird instar (0.11). Before the introduction ofA. citricola, the highest proportion ofhosts killed by predation was observed insecond instar (0.17) and third instar (0.15).After the establishment of the introducedspecies, the proportion of dead individuals dueto predation was greater for second instar(0.31) and third instar (0.21) larvae.Mortality caused by indigenous natural enemieswas significantly correlated with increases ofP. citrella density. Parasitism ofP. citrella by the exotic parasitoid,A. citricola, correlated less well to hostdensity over the season (r² = 0.12) thandid mortality caused by indigenous naturalenemies (r² = 0.76). Moreover, a higherpercent mortality in population of P. citrellawas obtained from predation by theindigenous natural enemies than the introducedparasitoid as shown in the mortality estimatesfrom 1995 to 1998.     

Genetic analysis of the susceptibility to neurological manifestations in spinal osteochondrosis

Complex genetic-mathematical analysis (component decomposition of the phenotype variance, segregation analysis, estimation of penetrance parameters) of 324 probands' families with neurologic manifestation of spinal osteochondrosis (3437 relatives of I-III degree) has been carried out is shown that the structure of liability to the disease studied is better approximated by semi-continuous phenotype model within the limits of which contribution of genetic factors reaches 80% (63-66% owing to autosomes and 14-17% owing to gonosomes) under considerable influence (20%) of environmental force (14% accidental and 6% systematic).     

Effects of gamma radiation on the reproduction biology and mating competitiveness of citrus leafminer Phyllocnistis citrella Stainton

The citrus leafminer (CLM), Phyllocnistis citrella Stainton, is one of the most serious pests of Iran's citrus nursery stocks. In this study, the effects of gamma radiation at doses of 100–450?Gy on the biological and reproductive parameters of P. citrella were determined. The results showed that the mean percentage of pupal mortality increases with a rise in the dose. Also, the mean values of this parameter were higher for irradiated females, indicating higher sensitivity. The mean fertility of the irradiated females mated with normal males was affected drastically and reached zero at 300?Gy. The hatchability of the eggs laid by normal females mated with irradiated males dropped to 2% at the highest irradiation dose of 450?Gy. The results of this test showed that females have a higher radio-sensitivity than males. The competitiveness values fluctuated from 0.2 to 0.6 at doses higher than 200?Gy. The results showed that the male CLMs irradiated with sterilizing doses could compete suitably with the untreated males in laboratory conditions.     

Genetic and phenotypic analysis of seizure susceptibility in PL/J mice

Epilepsy is one of the most common but genetically complex neurological disorders in humans. Identifying animal models that recapitulate human epilepsies is important for pharmacological studies of anticonvulsants, dissection of molecular and biochemical pathogenesis of epilepsy, and discovery of epilepsy susceptibility genes. We discovered that the PL/J inbred mouse strain is susceptible to handling- and rhythmic tossing–induced seizure. The tonic–clonic and generalized seizures observed after induction were accompanied by abnormal EEGs, similar to seizures observed in EL and SWXL-4 mice. PL/J mice also had an extremely low threshold to electroconvulsive seizures compared to other strains and showed variable sensitivity to pentylenetetrazole-induced seizures. Gross neurostructural abnormalities were not found in PL/J mice. Crosses with the seizure-resistant C57BL/6 J strain revealed semidominant inheritance of the rhythmic tossing seizure trait with low penetrance. F2 progeny indicated that the genetic inheritance of seizure susceptibility in PL/J is non-Mendelian. We crossed DBA/2 J mice, which are resistant to rhythmic tossing seizure but susceptible to audiogenic seizures, to PL/J. We found that seizure penetrance in (DBA/2 J × PL/J)F1 mice was similar to the penetrance in (C57BL/6 J × PL/J)F1 mice but the severity and frequency of seizure were higher in (DBA/2 J × PL/J)F1 mice. The PL/J strain serves as an interesting new model for studying the genetics, neurobiology, and pharmacology of epilepsy.     

Season‐long mating disruption of citrus leafminer,Phyllocnistis citrella Stainton,with an emulsified wax formulation of pheromone

The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), is a major worldwide pest of citrus. Larval feeding by this insect facilitates proliferation of citrus bacterial canker, Xanthomonas axonopodis pv. citri. Herein, we describe a season‐long disruption trial of P. citrella with a newly developed, emulsified wax dispenser of pheromone (SPLAT‐CLM^TM). A formulation containing a 3 : 1 blend of (Z,Z,E)‐7,11,13‐hexadecatrienal:(Z,Z)‐7,11‐hexadecadienal at a 0.2% loading rate of active ingredient by weight and deployed twice per season (24 weeks total) at 490 g of formulation/ha caused season‐long disruption of male moth catch in pheromone traps as well as reduced leaf infestation. Analysis of pheromone release from dispensers by gas chromatography revealed that effective disruption of P. citrella occurred at a deployment rate of 126 μg of (Z,Z,E)‐7,11,13‐hexadecatrienal/ha/h. Direct observation of moth behaviour in the field suggested that disruption by this formulation occurred by a non‐competitive mechanism. A formulation of the 3 : 1 attractive blend at a 0.02% pheromone loading rate caused only 2–6 weeks of disruption per deployment and did not reduce leaf infestation during mid and end of the season evaluations. A formulation containing 0.2% of (Z,Z)‐7,11‐hexadecadienal alone and deployed at 490 g/ha caused 6–7 weeks of moth disruption to pheromone traps and did not prevent leaf infestation, while an identical formulation loaded with 0.02% (w/w) of (Z,Z)‐7,11‐hexadecadienal alone had no effect on P. citrella orientation to pheromone traps. The SPLAT formulation evaluated herein appears to be an excellent release device for (Z,Z,E)‐7,11,13‐hexadecatrienal given that approximately 100 days of steady release occurred following an initial brief (ca. 7 days) burst of higher release. The advantages of SPLAT as a formulation for P. citrella disruption include low cost of manufacturing, biodegradable and weather resistant characteristics, and flowability allowing machine application. Mating disruption should be an effective alternative to insecticides for management of P. citrella and may reduce the incidence of citrus canker.     

Genetic susceptibility in Parkinson's disease

It is hoped that an understanding of the genetic basis of Parkinson's disease (PD) will lead to an appreciation of the molecular pathogenesis of disease, which in turn will highlight potential points of therapeutic intervention. It is also hoped that such an understanding will allow identification of individuals at risk for disease prior to the onset of motor symptoms. A large amount of work has already been performed in the identification of genetic risk factors for PD and some of this work, particularly those efforts that focus on genes implicated in monogenic forms of PD, have been successful, although hard won. A new era of gene discovery has begun, with the application of genome wide association studies; these promise to facilitate the identification of common genetic risk loci for complex genetic diseases. This is the first of several high throughput technologies that promise to shed light on the (likely) myriad genetic factors involved in this complex, late-onset neurodegenerative disorder.     

Genetic susceptibility to prostate cancer

Prostate cancer is the most frequent malignant tumor among men over 50 years old. Its incidence varies according to countries and ethnic group. Known risk factors are race and positive family history of the disease. Familial aggregation (at least 2 cases in the family) is observed in about 20% of cases and an hereditary form of prostate cancer in 5%. This proportion increases with younger age at diagnosis. Six putative loci are already identified but undoubtedly, others will be found in forthcoming studies. The genetic heterogeneity observed in hereditary prostate cancer reflects variety of origins of the studied families. In some families, aggregation of prostate cancer and other cancers suggests the involvement of common predisposing genes. In other familial and in sporadic cases, the genetic component should be polygenic: prostate cancer wouldn't result to segregation of a major gene mutations transmitted according to a monogenic inheritance, but rather to sharing of alleles at many loci, each contributing to a small increase in cancer risk. Indeed, several genetic polymorphism were associated with an increased risk of developing prostate cancer and could explain the variations of prostate cancer incidence observed between populations.     

Genetic susceptibility to ankylosing spondylitis

Ankylosing spondylitis is a highly heritable, common rheumatic condition, primarily affecting the axial skeleton. The association with HLA-B27 has been demonstrated worldwide, and evidence for a role of HLA-B27 in disease comes from linkage and association studies in humans, and transgenic animal models. However, twin studies indicate that HLA-B27 contributes only 16% of the total genetic risk for disease. Furthermore, there is compelling evidence that non-B27 genes, both within and outwith the major histocompatability complex, are involved in disease aetiology. In this post-genomic era we have the tools to help elicit the genetic basis of disease. This review describes methods for genetic investigation of ankylosing spondylitis, and summarises the status of current research in this exciting area.     

Genetic susceptibility to Alzheimer disease

Alzheimer disease (AD) is the leading cause of dementia in the elderly. Less than a decade ago, it was questioned as to whether or not genes were even involved in anything but rare early onset AD. Since that time, using a variety of genetic epidemiological and molecular biological techniques, four loci have been identified that play a role in the genetic susceptibility of AD, AD presents as a prototype of the power of genetic techniques in defining the etiology of a complex disease.