高岭土颗粒涂布对中国梨喀木虱寄主选择、产卵的影响及应用效果

为探索可替代化学药剂防治中国梨喀木虱的措施,开展了高岭土颗粒涂布对其寄主选择、产卵影响及应用效果的研究。分别采用3.5%高岭土水溶液、清水对梨休眠枝和当年生枝叶进行喷雾涂布处理,于24、48、72、96 h监测选择条件下成虫分布情况,于96 h记录选择和非选择条件下各枝条上的卵量。采用高岭土水溶液对梨苗均匀喷雾涂布,通过被害叶率、单叶若虫量、虫龄指数、为害指数对应用效果进行评价。研究结果显示,在选择条件下,经高岭土涂布的枝条上成虫数量明显少于对照,高岭土涂布的枝条上冬型成虫数量在96 h时最低(0.5头/枝),96 h时着卵量(1.83头/枝)显著低于对照(30.83头/枝);高岭土涂布的枝叶上夏型成虫在72 h时最低(1.17头/枝),96 h时着卵量(12.33头/枝)显著低于对照(242.5头/枝);在非选择条件下,冬型和夏型成虫在高岭土涂布的枝条上着卵量(2.83和15.17头/枝)分别显著低于对照(25.17和170.42头/枝);供试植株在接虫45 d后为害最严重,高岭土涂布的植株被害叶率(54.17%)、单叶若虫量(2.29头/叶)、虫龄指数(3.79)、为害指数(0.41)分别显著低于为对照植株(98.61%、11.72头/叶、4.13、0.95)。上述结果表明,高岭土涂布对中国梨喀木虱成虫的寄主选择具有驱避效果,对雌成虫的产卵具有抑制作用;高岭土涂布可限制中国梨喀木虱种群增长,降低危害水平。研究结果为中国梨喀木虱的综合治理提供了现实依据。     

Action of particle films on the biology and behavior of pear psylla (Homoptera: Psyllidae)

Particle films with different properties have been developed for arthropod pest control. Two basic film types are hydrophobic and hydrophilic films. The hydrophilic film formulations differ in the amount and kind of spreader-sticker that is incorporated into the kaolin particles. The effects of particle film type (hydrophobic versus hydrophilic) and formulation (Surround versus Surround WP) on the biology and behavior of pear psylla, Cacopsylla pyricola (Foerster), were investigated on pear in a series of laboratory studies. Scanning electron microscopy determined that the number of particles that attached to the front tibia of adult psylla differed by particle formulation but the particle sizes were fairly uniform and ranged from 3.6 to 4.5 microm in diameter. Adults had difficulty grasping particle film-treated leaves, and this effect was influenced by film type and leaf surface. Choice and no-choice tests indicated that adult settling and oviposition were very low, regardless of film type or formulation. Under no-choice conditions, adult mortality was low, in part, because the adults were able to feed through all 3% particle films, but at reduced rates. However, the mortality of adults sprayed with 3% particle film solutions ranged from 22.2 to 62.5% within 72 h after treatment, and mortalities differed most between the hydrophilic formulations. Nymphs born on particle film-treated foliage incurred high mortalities ranging from 58.9 to 82.0% by the time they reached the fifth instar and were affected most by particle film type. Nymphal development was not affected by particle film type or formulation. Egg fertility and nymphal hatch also were unaffected by particle films. These studies determined that there are a number of biological effects particle films have on pear psylla beyond the deterrence of adult settling and oviposition.     

Field evaluation of a botanical natural product against the pear psylla (Homoptera: Psyllidae)

A 2-yr field study was conducted to evaluate a botanical natural product, AkseBio2, for control of pear psylla, Cacopsylla pyri L. (Homoptera: Psyllidae). Three applications were made each year. Whereas the first application was applied at the dormant period (just before the first eggs were deposited by overwintered females), the second and third applications, respectively, were against the first and second summer generations of pear psylla. The first application deterred winterform females from depositing eggs until the clusterbud stage (buds expanded but no blossoms open) of tree development. In the second and third applications, the product reduced the number of psyllid eggs and young (first and second) instars, causing up to 79.4 and 81.1% mortality, respectively. However, it was less active against the older (third-fifth) instars and achieved only up to 52.7% mortality. Reduction in egg laying was greater than that caused by amitraz, the most commonly used conventional pesticide for psylla control in Turkey. There were no significant horticultural changes on treated plants up to 7 d after treatment in any trial, nor was there any phytotoxicity on plant tissue as a result of AkseBio2 treatments.     

Sampling of Cacopsylla pyri (Hemiptera: Psyllidae) and Pilophorus gallicus (Hemiptera: Miridae) in pear orchards

The psyllid Cacopsylla pyri L. (Hemiptera: Psyllidae), is one of the principal pests of pear (Pyrus spp.) orchards and, along with its natural enemies, needs to be carefully monitored for correct integrate pest management and biological pest control decision making. We compare sampling techniques and develop sampling methods for C. pyri and Pilophorus gallicus Remane (Heteroptera: Miridae). Four pear orchards were sampled periodically from 2007 to 2010 in southern Spain by beating branches into funnels or 45-cm-diameter nets and taking shoot samples. Different sampling techniques were compared, and several sampling methods were assayed for adults and nymphs of C. pyri and P. gallicus. Psylla adult and P. gallicus counts in the nets and funnels were similar and closely correlated. Counts of C. pyri adults in the funnels and nets were higher than on shoots, but all measures were closely correlated. The number of nymphs on shoots and leaves was correlated, as were the counts on leaves within shoots. A guide for choosing the sampling unit in cost/precision terms is given. C. pyri nymphs and adults showed an aggregated distribution, whereas P. gallicus had a less-crowded spatial distribution. Enumerative sequential sampling was evaluated for both insects by using the different sampling techniques by resampling experimental data. The negative binomial distribution fitted the experimental data gathered using the different sampling techniques for C. pyri adults and P. gallicus. The use of binomial sampling is discussed for the two insects and the costs involved are compared with those implied in the sequential enumerative method.     

Interplant movement by pear psylla (Homoptera: Psyllidae): Effects of sex ratio and reproductive status

Sticky trap catch of pear psylla,Cacopsylla pyricola Foerster, is male biased during the reproductive generations, but not the diapausing generation. In cage studies, we monitored movement by male and female pear psylla between host plants, and tested whether reproductive and diapausing psylla exhibit similar rates of movement. We also experimentally varied sex ratio to determine whether sex ratio affected movement. Male-biased sex ratios prompted increased movement off of the original host by male psylla of the reproductive generations; no such effect was noted for diapausing insects. We interpret these results to indicate that male movements increased under male-biased conditions due to mate-searching activities. There was also evidence in two experiments that severely male-biased sex ratios prompted movement off of the original host plant by reproductive females; this effect may have been due to harassment of ovipositing females by males.     

Pear transformed with a lytic peptide gene for disease control affects nontarget organism,pear psylla (Homoptera: Psyllidae)

The biology and behavior of pear psylla, Cacopsylla pyricola Foerster, on a transgenic clone of 'Bartlett' pear, Pyrus communis L., containing a synthetic antimicrobial gene, D5C1, was compared with that of a nontransgenic parental clone to determine whether there were any nontarget effects. The gene construct also contained the marker gene nptII (aminoglycoside 3'-phosphotransferase II) that encodes for antibiotic resistance to identify transformed plants. The purpose of the original transformation was to enhance pear resistance to the bacterial disease fireblight caused by Erwinia amylovora (Burr.) Winslow et al. The biology and behavior of pear psylla on a transgenic clone were compared with a nontransgenic parental pear clone in short- (< or = 7-d) and long-term (32-d) studies. Short-term studies indicated pear psylla adults preferred to settle and oviposit, and nymphs fed more and developed slightly faster, on transgenic pear compared with nontransgenic pear. In contrast, a long-term study on psylla colony development showed considerably fewer eggs, nymphs, and adults were produced on transgenic pear. Although adults reared on transgenic pear did not have weight affected, females produced fewer eggs and nymphal hatch was significantly reduced on the transgenic pear clone. Our results suggest that pear psylla biology and behavior are initially enhanced on this transgenic pear clone. However, chronic exposure of psylla populations to transformed pear plants that express the nptII marker and lytic peptide genes had detrimental effects on pear psylla reproductive biology. Field studies would be required to determine the specific effects of each gene on pear psylla biology and behavior and whether these effects would be expressed under natural conditions. The four-fold reduction in psylla population levels that resulted on this disease resistant transgenic pear line would be an added benefit to a pear integrated pest management (IPM) program. Overall, this study demonstrates that genetically altering plants to control one particular organism can have unintentional yet beneficial effects against other nontarget pest organisms in agricultural crops.     

Resistance of pear psylla (Cacopsylla pyri L.; Hom., Psyllidae) to deltamethrin and synergism with piperonyl butoxide

Abstract: Topical application bioassays, conducted on French populations of Cacopsylla pyri , showed resistance rates to deltamethrin ranging from 31-fold at the adult stage to 135-fold at the last larval stage. Synergism studies between deltamethrin and piperonyl butoxide (PBO), applied either topically or by tarsal contact with PBO, showed (i) that the rates of synergism were more than 10-fold in all the populations and that they could increase to a thousand-fold in some populations, (ii) that the synergistic effect was present to a similar extent at both the larval and adult stages, (iii) that there was no correlation between the synergistic effect and the resistance rates, and (iv) that no correlation was observed between the dates of collection and the rates of synergism. The results makes it impossible to determine whether resistance to deltamethrin is of genetic origin or results only from the induction of monooxygenases by allelochemical substances present in the food ingested by the species.     

Seasonal variation in susceptibility of the pear psyllid,Cacopsylla permixta (Hemiptera: Psyllidae) to selected insecticides

Although Cacopsylla pyri Forster and Cacopsylla pyricola Linnaeus have long been considered as more significant pests of pear trees around the world, Cacopsylla permixta Burckhardt and Hodkinson is the most significant pest in some parts of Iran, especially in pear gardens of Karaj. Current control strategies against this pest in Iran generally involve five or six insecticide treatments each year, despite unsatisfactory results are reported at many localities. So, it is crucial to know the most susceptible generation of the pest to apply a good strategy for its control. The aim of this study was to explore the seasonal variation in susceptibility of C. permixta to four commonly used insecticides. The results showed that winter forms (February) were 2.71‐fold, 4.58‐fold, 3.26 fold and 3.38‐fold more tolerant to diazinon, imidacloprid, acetamiprid and abamectin, respectively, compared with summer forms. Also, Esterase, GST and P450 monooxygenase activity was highest during February. Moreover, the content of lipid, carbohydrate, glycogen and protein was significantly higher in February compared with other months. Based on these results, the best period for insecticide treatment for efficient control is treatment against the first generation, at the time when eggs are laid by females as well as during the egg hatching and the larvae appearance. At this time of year, psylla are more susceptible, which would likely lead to better results and the reduction in damage during the next summer. However, further studies are needed to test this in farm settings, and to whether this holds true for other psylla species.     

梨木虱化学感受蛋白CchiCSP8与梨树挥发物的结合特性分析

【目的】梨木虱Cacopsylla chinensis是我国重要的梨树害虫。本研究通过分析梨木虱化学感受蛋白8(chemosensory protein 8, CchiCSP8)与梨树挥发物的结合特性,综合研究CchiCSP8的嗅觉功能,为今后阐释梨木虱定位梨树的嗅觉机理提供前期基础。【方法】采用PCR方法克隆CchiCSP8的全长开放阅读框序列,并对推导的氨基酸序列与其他半翅目昆虫CSPs进行同源比对和进化分析;构建pET30a(+)-CchiCSP8的原核表达载体,通过大肠杆菌Escherichia coli体外表达、组氨酸标签蛋白镍磁珠纯化技术和荧光竞争性结合实验,共测定了重组蛋白CchiCSP8与41种梨树挥发物的结合能力。随后对CchiCSP8进行同源建模和分子对接分析。【结果】克隆获得了CchiCSP8全长序列,开放阅读框全长426 bp,编码141个氨基酸,N端有一个包含21个氨基酸的信号肽。成熟的CchiCSP8蛋白的预测分子量和等电点分别为15.02 kD和9.77;与其他半翅目昆虫CSPs的序列比对发现,CchiCSP8具有4个保守的半胱氨酸位点,并与柑橘木虱Diaphorina citri化学感受蛋白DcitCSP11的进化关系最近;pET30a(+)-CchiCSP8在IPTG诱导下在大肠杆菌中成功表达,并通过镍磁珠纯化获得纯净的CchiCSP8蛋白;采用荧光竞争性结合实验分析重组蛋白CchiCSP8的结合特性,结果显示CchiCSP8对18种梨树植物挥发物具有不同程度的结合能力(Ki=14~30 μmol/L),包括4种烯烃、6种醇类、4种醛类、1种酮、1种酯类和2种芳香类物质,CchiCSP8与配体的结合力表现出了随碳原子数不同而变化的特点;分子对接结果显示CchiCSP8和每个配体之间的结合能相差不大(-4.2~6.0 kJ/mol),这与上述荧光竞争结合实验的结果一致。在CchiCSP8与不同配体结合过程中,存在多个共有氨基酸残基,其中5个非极性残基(A38, A42, L93, L99和V100)以及2个极性残基(Q107和K46)的作用最为突出。【结论】CchiCSP8能够结合18种不同类型的梨树挥发物,推测其在梨木虱识别梨树挥发物的过程起到重要作用,本研究结果可为明晰梨木虱在定位梨树过程中的嗅觉机制提供理论基础,并为开发基于扰乱嗅觉行为的新型梨木虱行为调控技术提供新思路。     

Genetic analysis of resistance to azinphosmethyl in the pear psylla Cacopsylla pyri

Laboratory selection with azinphosmethyl had little effect on the chemical resistance in Cacopsylla pyri strains, in comparison to the original wild populations. The resistance ratio relative to a susceptible strain varied from 10- to 40-fold depending on the generation studied. Crosses between two resistant strains and the susceptible strain show resistance to be autosomally inherited and semi-dominant in expression. Backcrosses between F1 and the susceptible strain were unable to distinguish unabigously between monogenic and polygenic inheritance. In the majority of experiments, however, the overall dose-response relationship for backcross progeny was consistent with a single gene hypothesis. Additional bioassays showed azinphosmethyl-resistant strain to cross-resistant monocrotophos and phosmet, but not carbamates, pyrethroids, amitraz or the organophosphates chlorpyrifos and mevinphos.     

Fine structure and sensory apparatus of the mouthparts of the pear psyllid,Cacopsylla chinensis (Yang et Li) (Hemiptera: Psyllidae)

The pear psyllid, Cacopsylla chinensis (Yang et Li) (Hemiptera: Psyllidae), is one of the most significant economic pests of pear in China, causing direct damage through feeding by the highly specialized piercing–sucking mouthparts. The ultrastructural morphology and sensory apparatus of the mouthparts of the adult were examined using scanning and transmission electron microscopy. The piercing–sucking mouthparts of C. chinensis are composed of a three-segmented labium with a deep groove in the anterior side, a stylet fascicle consisting of two mandibular and two maxillary stylets, and a pyramid-shaped labrum. Proximal to the labium, the stylet fascicle forms a large loop within a membranous crumena. Mandibles, with more than ten teeth on the external convex region, can be seen on the distal extremity. Smooth maxillary stylets are interlocked to form a larger food canal and a smaller salivary canal. One dendritic canal housing 2 dendrites is also found in each mandible. Two types of sensilla trichodea, four types of sensilla basiconica, single as well as groups of sensilla campaniformia, and oval flattened sensilla occur in different locations on the labium, whereas a kind of sensilla basiconica is at the junction of the labrum and anteclypeus. Sensilla trichodea and sensilla campaniformia, always present with denticles, are present on the middle labial segment. Three types of sensilla basiconica, two types of sensilla trichodea and two oval flattened sensilla are located on the distal labial segment. The mouthpart morphology and abundance of sensilla located on the labium in C. chinensis are illustrated, along with a brief discussion of their taxonomic and putative functional significance.     

Life history and demography of Psyllaephagus zdeneki (Hymenoptera: Encyrtidae), a potential candidate for biological control of olive psylla,Euphyllura pakistanica (Hemiptera: Psyllidae)

Life history and demographic parameters of Psyllaephagus zdeneki Noyes and Fallahzadeh (Hymenoptera: Encyrtidae) were studied on its host the olive psyllid, Euphyllura pakistanica Loginova (Hemiptera: Psyllidae). Experiments were conducted in a growth chamber at 20±1 °C, relative humidity of 60±5%, and a photoperiod of 16:8 (L: D) hours. Four different olive cultivars (Fishomi, Shenge, Oil and Yellow) were used to test possible host plant influence on parasitoid performance. The pre-imaginal developmental period of female P. zdeneki varied from 24.96 (on Fishomi) to 26.34 (on Shenge) days, and for males from 21.63 (on Fishomi) to 24.44 (on Yellow) days. Adult female longevity differed significantly among the four cultivars, ranging from 12.46 (on Fishomi) to 14.97 (on Shenge) days. For each cultivar, adult female longevity was significantly greater than male longevity. Life table parameters showed survival rates (l _x ) in newly emerged females were 84.61, 82.25, 85.71 and 78.12% on Fishomi, Yellow, Shenge and Oil, respectively. Female egg deposition was highest on Yellow (138.4 eggs per female) and lowest on Fishomi (116.3 eggs per female). The highest and lowest intrinsic rate of increase were 0.28 (on Shenge) and 0.24 (on Oil), respectively. The mean generation time ranged from 14.6 (on Shenge) to 16.7 (on Oil) days. These results are discussed with respect to the potential impact P. zdeneki as a natural enemy of E. pakistanica, the most important pest of olive in the Fars province of Iran, as well as the influence of olive cultivar on parasitoid life table parameters.     

New species of Acizzia Heslop-Harrison (Hemiptera: Psyllidae) from Australian mistletoe (Loranthaceae)

Three new species of Acizzia are described from Australian mistletoe (Loranthaceae: Amyema spp.). These are: A. loranthacae sp. n., A. amyemae sp. n. and A. pendulae sp. n. They are characterised by: male proctiger with prominent posterior lobe; antenna 1.9–2.9 times width of head; forewing with costal break and pterostigma, with pattern in A. amyemae and A. pendulae but not in A. loranthacae ; and female proctiger simple in A. amyemae and A. pendulae but with prominent dorso-apical process in A. loranthacae . The Loranthaceae is a new host family record for Acizzia . Given the probable radiation of Acizzia on mimosaceous hosts, its occurrence on eucalypt-inhabiting mistletoe, yet its apparent absence from mistletoes on Acacia, is discussed.     

Population dynamics of Cacopsylla melanoneura (Hemiptera: Psyllidae) in northeast Italy and its role in the apple proliferation epidemiology in apple orchards

In the current study, incidence of 'Candidatus Phytoplasma mali' in an experimental apple orchard in northeast Italy, in addition to abundance and phytoplasma infectivity of Cacopsylla melanoneura (F?rster) (Hemiptera: Psyllidae) was determined and the role of this psyllid as a vector of 'Ca. P. mali' in this region was reviewed. Insect samples collected in the orchard by the beating method indicated high abundance of C. melanoneura (up to 7.92 specimens/branch); however, the psyllid C. picta was not observed. Molecular analyses revealed presence of 'Ca. P. mali' in 6.25% of overwintered psyllids. This infection rate is quite high in comparison to other localities where C. melanoneura is known as the main vector of the phytoplasma. This finding supports the assumption that C. melanoneura also is paramount in the epidemiology of the apple proliferation disease also in northeast Italy. Moreover, we correlated immigration dynamics to the temperatures registered in the apple orchard, and defined an immigration index to predict the progressive arrival of the overwintered adults from winter sites. Psyllids start to reach the apple orchards when either the average of the maximum temperature of the 7 d is above 9.5 degrees C or the immigration index has a positive value. This index will be a useful tool for the growers to prevent apple proliferation phytoplasma spread with well-timed insecticide treatments targeted against C. melanoneura. However, further research is needed to validate or adjust the index to other apple growing regions, which may affect more efficacious management of this disease and psyllid vector.     

Dispersion patterns and sampling plans for Diaphorina citri (Hemiptera: Psyllidae) in citrus

The abundance and spatial dispersion of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) were studied in 34 grapefruit (Citrus paradisi Macfad.) and six sweet orange [Citrus sinensis (L.) Osbeck] orchards from March to August 2006 when the pest is more abundant in southern Texas. Although flush shoot infestation levels did not vary with host plant species, densities of D. citri eggs, nymphs, and adults were significantly higher on sweet orange than on grapefruit. D. citri immatures also were found in significantly higher numbers in the southeastern quadrant of trees than other parts of the canopy. The spatial distribution of D. citri nymphs and adults was analyzed using Iowa's patchiness regression and Taylor's power law. Taylor's power law fitted the data better than Iowa's model. Based on both regression models, the field dispersion patterns of D. citri nymphs and adults were aggregated among flush shoots in individual trees as indicated by the regression slopes that were significantly >1. For the average density of each life stage obtained during our surveys, the minimum number of flush shoots per tree needed to estimate D. citri densities varied from eight for eggs to four flush shoots for adults. Projections indicated that a sampling plan consisting of 10 trees and eight flush shoots per tree would provide density estimates of the three developmental stages of D. citri acceptable enough for population studies and management decisions. A presence-absence sampling plan with a fixed precision level was developed and can be used to provide a quick estimation of D. citri populations in citrus orchards.     

Detecting Cacopsylla pyricola (Hemiptera: Psyllidae) in predator guts using COI mitochondrial markers

Cacopsylla pyricola (F?rster) is one of the most important pests of pear in North America, where several native predators have been considered for integrated pest management (IPM) programmes. Two molecular markers of 271 and 188 bp were developed from C. pyricola cytochrome oxidase I (COI) fragments, in order to study the detection of this species in the gut of arthropod predators. Primer sensitivity and the detection period for pear psylla remains in the guts of Anthocoris tomentosus Pericart were determined. The sensitivity threshold was defined at 10-5 dilution of a C. pyricola fifth-instar nymph in all samples. Predator adults were evaluated immediately after ingestion of one to five C. pyricola nymphs (t = 0) and after 2, 4, 6, 8, 16, 24 and 32 h. Detection of the presence of C. pyricola DNA always lasted longer using the shorter fragment and was observed after 32 h of digestion using both markers. The primers amplifying the 188 bp fragment amplified all four psyllid species tested, whereas the primers designed to amplify the 271 bp fragment did so exclusively for C. pyricola and its close relative, Cacopsylla pyri (Linnaeus). Both primers failed to amplify DNA from representative species of the Coccinellidae, Chrysopidae, Hemerobiidae, Anthocoridae, Miridae, Salticidae, Aphididae, Tetranychidae and the Tortricidae, suggesting their suitability for general trophic studies.     

中国新入侵害虫——桉梳木虱(半翅目:木虱科)

2018年5月,在云南省昆明市金殿森林公园种植的蓝桉树苗上采集到了一种密集发生的木虱,其成虫和若虫均严重危害桉树叶片。经鉴定为桉梳木虱,该种木虱原产于澳大利亚,此前已入侵欧洲、非洲、北美洲、南美洲和亚洲的一些国家,危害桉树。本文提供了桉梳木虱的危害情况和形态鉴别特征,提出了防范扩散危害的措施建议。     

Transmission parameters for Candidatus liberibacter asiaticus by Asian citrus psyllid (Hemiptera: Psyllidae)

The purpose of this investigation was to evaluate acquisition and inoculation (together, transmission) efficiency of Candidatus Liberibacter asiaticus (Las), the pathogen associated with citrus huanglongbing (HLB) by the Asian citrus psyllid, Diaphorina citri (Kuwayama) (Hemiptera: Psyllidae). In laboratory studies, nymphs reared on Las infected plants were more likely to acquire the bacterium than adults. Acquisition by nymphs ranged from 60 to 100%, whereas acquisition by adults only reached 40% after 5 wk of feeding on Las-infected plants. Similar rates of pathogen acquisition by psyllids after nymphal and adult feeding were observed in the field. Transmission of Las from parent to offspring (transovarial) occurred at a rate of 2-6%. One year after psyllid inoculations, successful transmission by individual D. citri ranged from 4 to 10%, whereas groups of 100 or more D. citri transmitted the pathogen at a rate of approximately 88%. In addition, the proportion of Las-positive adult psyllids, determined using quantitative real-time polymerase chain reaction, decreased over time when held on healthy plants. Due to the low rate of pathogen acquisition and long time period required for successful inoculation by adult D. citri, experiments designed to determine the latent period required for replication and successful inoculation of Las by D. citri did not result in Las-infected plants after >1 yr of incubation after inoculation. Collectively, these results indicate that adult D. citri which acquire the HLB pathogen as adults are poor vectors of the pathogen compared with adults that acquired the pathogen as nymphs.     

Life table of Tamarixia radiata (Hymenoptera: Eulophidae) on Diaphorina citri (Hemiptera: Psyllidae) at different temperatures

Tamarixia radiata (Waterston, 1922) is the main parasitoid of Diaphorina citri (Kuwayama, 1907), and has been used in classical biological control programs in several countries. The current study investigated the biology and determined the fertility life table of T. radiata in different temperatures, to obtain information to support the establishment of a biological control program for D. citri in Brazil. Fifth-instar nymphs of D. citri were offered to females of T. radiata for parasitism, for 24 h. Then, the parasitoid was removed and the nymphs were placed in incubators at 15, 20, 25, 30, or 35 +/- 1 degrees C, 70 +/- 10% RH, and a 14-h photophase. The percentages of parasitism and emergence, the sex ratio, and the preimaginal period of T. radiata were determined. The fertility life table was developed from the biological data. The highest parasitism rate (77.24%) was obtained at a temperature of 26.3 degrees C, and the lowest parasitism rates occurred at 15 and 35 degrees C (23.1 and 40.2%, respectively). The highest percentages of emergence of the parasitoid occurred at 25, 30, and 35 degrees C (86.7, 88.3, and 78.8%, respectively), with the calculated peak at 30.8 degrees C (89.90%). The duration of the preimaginal developmental period for both females and males of T. radiata was inversely proportional to temperature in the thermal range of 15-35 degrees C. The development of T. radiata occurred at all temperatures studied, and the highest viability of the preimaginal period occurred at 25 degrees C. The highest values of net reproductive rate and finite growth ratio (lambda) were observed at 25 degrees C, so that in each generation the population of T. radiata increased 126.79 times, higher than the values obtained at the other temperatures.