不同温湿度组合对安徽虫瘟霉 诱发桃蚜病害的影响

用孢子浴方法,对42批次桃蚜Myzus persicae（30～60头/批）接种大剂量（孢子79～90个/ mm²）安徽虫瘟霉Zoophthora anhuiensis的分生孢子,在20℃下保湿24 h后转入不同温度（10℃、15℃、20℃、25℃、30℃及自然变温1.5～16.6℃和8.5～20.2℃）和湿度(50%、65%、80%、90%、95%及100% RH)的组合条件下观察桃蚜的反应。结果表明,各组合条件下的桃蚜均能发病死亡,而且累计死亡率的显著差异存在于不同温度（F=7.46, P<0.01)和湿度间（F=12.54, P<0.01）。最适发病的温度为恒温20℃和变温8.5～20.2℃（日均温12.4℃）,死亡率随湿度升高而增大。在10～25℃和100% RH的组合中,温度的变化几乎不影响桃蚜的累计死亡率,但影响发病速率,在10℃、15℃、20℃和25℃下的致死时间LT₅₀值分别为8.4 天、7.1 天 、4.0 天和3.4 天。回归分析表明, 在100% RH下安徽虫瘟霉诱发桃蚜发病的起始温度为1.65℃。在10～15℃及自然变温下,病死蚜尸顺利产孢的湿度为80% RH;而在20～30℃下,蚜尸产孢的湿度为90% RH。在所有温湿组合的蚜尸中未见安徽虫瘟霉的休眠孢子发生。     

安徽虫瘟霉诱发的桃蚜流行病与流行模型

在15℃与100％RH的组合条件下以接种安徽虫瘟霉（Zoophthora anhuiensis)和未接种的桃蚜（Myzus persicae)成蚜按不同比例混合（0：6,1：5,2：4,3：3,4：2,5：1及6：0）建立蚜群,3次重复,考察流行病的发生与发展,结果表明,在带菌蚜50％以上的蚜群中,活蚜的数量增长因高强度的流行病发生而得到有效控制,活蚜数妈终未超过50头／90cm^2,第22天观察结束时与对照（0：6）jah vtk r 656udi /90cm^2相比控蚜效果高达93．24％－100％,在接菌与未接菌比例1：5和2：4的蚜群中,蚜病的发生虽未能充分控制蚜虫的数量增长,但结束时的蚜虫数量均显著低于对照,分别为356头／90cm^2和207头／90cm^2,控蚜效果亦分别达46％和68％,各处理蚜群中病害流行随时间的变化很好地拟合Gompertz模型（r^2=0.97),由此估计出虫瘟霉不同初始菌量在蚜群中的流行速度（R）及最高流行水平（K）,线性回归分析表明,初始侵染体密度确定了R（r^2=0.89)和K（r^2=0.90)估计值的90％变异,充分显示安徽虫瘟霉流行病的发生及流行强度对初始侵染体和寄主密度的依赖性。     

不同温湿度条件下飞虱虫疠霉对桃蚜生殖力和内禀增长力的影响

对7日龄桃蚜 Myzus persicae用高剂量飞虱虫疠霉Pandora delphacis接种后,饲养于不同温(10～30℃)、湿(74%～100%RH)度组合条件下观察其生殖力及内禀增长力(r_m) 的变化。结果表明,被接种个体生殖力比对照显著降低,且下降幅度受温度、湿度及温湿互作的影响。在各处理组合中,尤其以20～30℃和95%～100%RH的条件下下降更为明显。各处理r_m在不同温度间差异显著,均随温度呈抛物线形变化,25℃下达最高,但不同湿度间差异不显著。与对照相比,被接种蚜的r_m>除10℃与各湿度组合间无显著差异外,其余温湿组合下均显著低于对照。上述分析表明,飞虱虫疠霉的侵染能显著影响桃蚜生殖力及r_m,尤其是在桃蚜繁殖的最适温度范围内效果最为明显。     

环境因素对安徽虫瘟霉生长发育的影响

安徽虫瘟霉是目前仅发现于我国的重要蚜虫病原真菌,对桃蚜具有明显的自然控制作用。本研究了温度和紫外光对安徽虫瘟等固体培养性状及不同温湿度组合对安徽虫瘟霉分生孢子萌发的影响。     

飞虱虫疠霉继发性感染对桃蚜数量增长的控制作用

用飞虱虫疠霉（Pandora delphaics)“孢子浴”接种的桃蚜(Myzus persicae)无翅成蚜在离体甘蓝菜叶片（65cm^2)上建立蚜群,在不同温度（10－30℃）和湿度（74％－100％RH）的组合条件下任其繁衍,发病和交互感染,以评价该菌的控蚜效果。在25个温,湿度组合处理（8次重复,每重复含3头接种成蚜)中,蚜群均不同程度的发病死亡,在历时30d的观察中,以高温（20－30℃）,高湿（95％RH）组合条件下的蚜群发病快且死亡率高,蚜尸上产生的孢子有效地引起若蚜继发性感染。与相同温度下不带菌的对照蚜群相比,次于30℃下,各湿度除个别例外,第8d的控蚜率达30％以上,第20d达80％以上。在10℃和15℃下,控蚜效果一般不如上述较高温度下,且与湿度的关联程度相对较低,但最大控蚜效果均发生在100％RH处理中。结果表明,飞虱虫疠霉用于蚜虫防治的潜力很大,值得深入研究和开发利用。     

温度与光照对安徽虫瘟霉产孢格局的影响*

在不同温度（10～30℃）与光照（连续光照和连续黑暗）组合条件下进行了安徽虫瘟霉（zoophthoraanhuiensis）离体产孢格局的研究。结果表明,适于安徽虫瘟霉产孢的温度为10～20℃,但以15℃最适,不仅产孢快和产孢量大,而且不受光照的影响。在25℃下虽能产孢,但产孢量大幅减少,30℃下则不产孢,25℃可能是安徽虫瘟霉产孢的高温极限。全光照各温度处理的产孢量总是比全黑暗相应温度处理的产孢量高,说明光照对产孢具有刺激作用。在10℃和全光照的组合中,累计产孢量最高且持续产孢时间最长,而相同温度与全黑暗处理的产孢量却很低,显示光照在偏低温度下是影响安徽虫瘟霉产孢的关键因素。概而言之,光照主要影响安徽虫瘟霉的产孢量,而温度主要影响其产孢速率或进程。     

飞虱虫疠霉杀蚜效果及开发应用前景

通过比较飞虱虫疠霉 (Pandoradelphacis)与其它几种常见蚜虫专化性病原真菌新蚜虫疠霉(P .neoaphidis)、安徽虫瘟霉 (Zoothphoraanhuiensis)和根虫瘟霉 (Z .radicans)对桃蚜 (Myzuspersicae)毒力 ,证实了该菌的杀蚜应用潜力。时间 -剂量 -死亡率模型分析表明 ,飞虱虫疠霉杀蚜的各项毒力指标与其它几种虫霉相似或略高 ,但杀蚜速率更快。同时对培养性状、产孢特性和生长适温等的比较研究发现 ,该菌具有易发酵生产、产孢能力强和温度生长范围宽等特点 ,是一种较为理想的有望研制开发成杀蚜真菌制剂的病原菌。此外 ,根据虫霉孢子主动弹射的生物学特性 ,提出了该菌的适用剂型 ,并对它们的流行学特性及其在设栽培中的应用前景进行了讨论。     

温湿度对番茄刺皮瘿螨实验种群的影响

在同一湿度（53%RH）不同温度（14℃、17℃、20℃、23℃、26℃、29℃、32℃、35℃及同一温度（26℃）不同湿度（30%RH、53%RH、75.5%RH、85%RH、92.5%RH、100%RH）组合条件下,测定了温湿度对番茄刺皮瘿螨Aculops lycopersici (Massee)生长发育及繁殖的影响。结果表明,温、湿度对该螨存活率有明显影响,以23℃（53%RH）和75.5%RH（26℃）条件下最高,分别为89.9%和87.1%; 其发育历期较短,在14～35℃和30%～100%RH范围内,历期随温度升高而缩短,随湿度升高而延长; 番茄刺皮瘿螨的发育起点温度较高,卵、若螨和整个世代的发育起点温度分别为10.51、9.02和9.15℃。完成一代需要105.56日·度。温湿度对番茄刺皮瘿螨的繁殖力有明显影响,产卵期随温度升高而缩短,随湿度升高而延长; 产卵量在26℃(53%RH)和53%RH(26℃)下最高,每头雌虫产卵分别为44.3粒和42.2粒; 26℃(53%RH)和53%RH(26℃)条件下种群的内禀增长率最高,分别为0.2645和0.2669。结果表明,适宜的温湿度条件为温度26～29℃、相对湿度53%～75%。     

温度与光照对安徽虫瘟霉产孢格局的影响

在不同温度（１０－３０℃）与光照（连续光照和连续黑暗）组合条件下进行了安徽虫瘟霉（Ｚｏｏｐｈｔｈｏｒａ ａｎｈｕｉｅｎｓｉｓ）离体产孢格局的研究。结果表明,适于安徽虫瘟霉产孢的温度为１０－２０℃,但以１５℃最适,不仅产孢快和产孢量大,而且不受光照的影响。在２５℃下虽能产孢,但产孢量大幅减少,３０℃下则不产孢,２５℃可能是安徽虫瘟霉产孢的高温极限。全光照各温度处理的产孢量总是比全黑暗相应温度处理的产     

安徽虫瘟霉的黍米培养及其对桃蚜的侵染力

安徽虫瘟霉Zoophthora anhuiensis (Li) Humber是较难人工培养的蚜虫专化性病原真菌。将灭菌并适度熟化的黍米Panicum miliaceum L.作为固体基质与挑碎的安徽虫瘟霉平板菌落混合,在20℃和12L∶12D的温光条件下静止固体培养,获得了产孢潜能大、杀蚜活性强的米粒培养物。培养7天的黍米的产孢量达13.0×10⁴个孢子/粒,产孢持续时间长达6天。用此黍米培养物弹射的孢子对桃蚜Myzus persicae (Sulzer) 若蚜进行7.9～134.9个孢子/mm²共9个剂量的孢子浴接种,所获数据很好拟合时间 剂量 死亡率模型。接种后第5～7天各天的LC₅₀依次为59.8, 39.5和33.5个孢子/mm²,LC₉₀依次为354,234和198个孢子/mm²。在57.7～134.9个孢子/mm²的接种剂量范围内,致死中时LT₅₀从5.1天下降到4.3天。由此表明,安徽虫温霉的黍米培养不仅简单易行,而且菌种的产孢和侵染生物学特性在培养物中被充分体现,每颗米粒如同自然罹病而死的蚜尸,值得进一步研究开发和利用。     

Experimental epizootiology of Zoophthora anhuiensis (Entomophthorales) against Myzus persicae (Homoptera: Aphididae) with a description of a modified Gompertz model for aphid epizootics

Epizootiological features of Zoophthora anhuiensis, a fungal pathogen specific to aphids in southern China, were studied in six aptera colonies of Myzus persicae at 16 regimes of temperature (T = 10, 15, 20 and 25 degrees C) and relative humidity (H = 90%, 95%, 98% and 100% RH) with initially infected proportion (Ip) of 0.5 in experiment (Expt) 1 or at a fixed regime of 15 degrees C and 100% RH with a variable Ip of 0.17-1.00 in Expt 2. Mycosis-caused mortalities (Mp) varied with aphid densities (D) over time after colony initiation (t) were well fitted to a Gompertz growth model modified to include the variables T, H, Ip and D in the form of Mp = 91.72exp[-5.282exp[-(0.0095T + 0.0128H/T-0.5407D2/H)t]] for Expt 1 (r2 = 0.94) or Mp = 95.49exp[-4.314exp[-(0.1479Ip + 0.1636/D)t]] for Expt 2 (r2 = 0.97). These variables were effective in determining the rate of epizootic development in the M. persicae colonies. Based on the observed and fitted results, Z. anhuiensis was most adaptive to cool climate or season and epizootiologically was subject to a minimal effect of RH at an optimum of approximately 15 degrees C. However, the humidity became determinant for epizootic progress at higher temperatures. Interactive effects of the variables and application of the fitted models for predicting epizootic development in field situations are discussed.     

Effects of fluctuating moisture and temperature regimes on the infection potential of Beauveria bassiana for Rhodnius prolixus

The effect of both moisture and temperature on the infective potential of Beauveria bassiana to the Chagas' disease vector, Rhodnius prolixus, was studied under fluctuating regimes. At constant 25 degrees C, contaminated first-instar nymphs exposed to increasing daily periods of initial exposure to 97% RH, followed by transfer to reduced humidity (43, 53, 75, and 86% RH), showed a significant reduction in mortality when the 97% RH exposure time declined from 12 to 8 h per day. The duration of disease incubation depended on the daily 97% RH exposure time. Under fluctuating regimes of both humidity (97% RH versus 75% RH) and temperature (15/28, 20/25, 25/28, and 25/35 degrees C), first-instar mortality was affected by weather conditions, daily 97% RH exposure time (8, 12, and 16 h per day), and number of temperature and humidity fluctuations before transferring tested insects to constant unfavorable conditions. In most cases, at 12/12 h alternating cycles, high and rapid mortality required five cycles. Under these fluctuating regimes, fungus-induced mortality and mortality time were similarly affected in third- and fifth-instar nymphs by the daily 97% RH exposure time. Despite a lower susceptibility of older larval stages, mortality rates in insects exposed for at least 12 h per day at 97% RH remained very high except at 15 degrees C. Moisture and temperature regimes at 12/12 h cycling significantly affected the dose-mortality response in first-instar nymphs. The most favorable conditions consisted of 97%-20 degrees C combined with either 75%-25 degrees C or 43%-25 degrees C. Under less favorable alternating conditions (lower and higher temperatures) the amounts of inoculum required for killing 50% of first-instar nymphs were 10 or 20 times higher. From a vector control standpoint, daily high humidity appears to be the most crucial climatic constraint. B. bassiana has the potential to control R. prolixus populations with applications made during the rainy seasons when humidity is high.     

Factors affecting the sporulation capacity during long-term storage of the aphid-pathogenic fungus Pandora neoaphidis grown on broomcorn millet

Aphid-pathogenic fungus, Pandora neoaphidis, grown on broomcorn millet possesses greater sporulation capacity (C(s)) than aphid cadavers. The most sporulating cultures (32.0x10(4) spores millet(-1) grain) with water content (C(w)) of 48.7% were prepared by incubation at 20 degrees C for 15 days and used to study the effect of temperature and humidity on C(s) during long-term storage. Cultures were sealed with paper to retain ambient humidity, with parafilm for saturated humidity, or kept in 85% and 98% RH chambers. The C(w) and C(s) were monitored during 200-day storage at 5-20 degrees C. The paper-sealed cultures at 5 degrees C, associated with 21-25% of C(w), were best preserved and their 120-day C(s) was similar to that of the fresh cadavers. Consistently or variably high RH at 5 degrees C resulted in significantly higher C(w) and lower C(s) despite longer viability. The regimes at 10 degrees C preserved the cultures for 40 days. The observations fit well to the logistic model C(s)=35.28/{1+exp[-2.36+(-0.003C(w)+0.001C(w)T)t]} (r(2)=0.95) for all regimes of temperature (T) or C(s)=35.55/[1+exp(-2.33+0.001C(w)t)] (r(2)=0.93) at 5 degrees C only. The rate of decline of C(s) of -0.003C(w)+0.001C(w)T or 0.001 C(w) over days (t) highlights the primary effect of C(w). The daily C(s)-decline rates obtained for the best-stored cultures and air-dried cadavers stored at 5 degrees C were surprisingly identical. The results suggest a possible cheap method for preparing and storing large quantities of P. neoaphiodis inocula.     

Influence of temperature on the hygropreference of the Collembolan, Cryptopygus antarcticus, and the mite, Alaskozetes antarcticus from the maritime Antarctic

The hygropreference of adult Cryptopygus antarcticus and Alaskozetes antarcticus was investigated over 2 h at 5, 10 and 20 degrees C, along humidity gradients (9-98% RH) established by means of different salt solutions. Two chamber arrangements were employed, linear and grid, to determine any influence of thigmotactic behaviour on distribution within the RH gradient. The humidity preference of both species varied with temperature. At 5 and 10 degrees C, C. antarcticus distributed homogeneously showing no clear RH preference. At 20 degrees C, this species preferred the highest humidity (98% RH). A. antarcticus demonstrated a preference for the lowest humidity (9% RH) at 5 degrees C, but at 10 degrees C its distribution differed between the two arena types. At 20 degrees C, A. antarcticus showed no clear humidity preference. Assays to control for experimental asymmetries along the gradient; thigmotactic behaviour; and aggregative behaviour exclude these factors as explanations for the observed results. The mean initial water content of samples did not differ significantly between temperature regimes (C. antarcticus: 68.6, 71.1 and 74.3%; A. antarcticus: 68.1, 70.1 and 68.6% at 5, 10 and 20 degrees C respectively), but the level of water loss increased significantly with temperature. The influence of desiccation tolerance and the ecological significance of the observed humidity preferences are discussed.     

Influence of temperature, photoperiod and humidity on oviposition and egg hatch of the root-feeding flea beetle Longitarsus bethae (Chrysomelidae: Alticinae), a natural enemy of the weed Lantana camara (Verbenaceae)

The root-feeding flea beetle Longitarsus bethae Savini & Escalona, was introduced into South Africa as a candidate biological control agent for the noxious and invasive weed, Lantana camara L. As part of the study to predict the beetles' survival in its new range, the influence of climatic conditions on its egg development and reproductive performance were investigated in the laboratory. The threshold temperature (T degrees) and degree-days (DD) required for egg hatch were determined after exposing the eggs to various constant temperatures (12, 17, 22, 27 and 32 degrees C) in separate growth chambers. The DD required for egg hatch was 178.6, and the temperature threshold required for egg hatch was 11.3 degrees C. Survival of eggs varied from 27 to 56% at 32 and 17 degrees C, respectively, and was optimum between 17 and 25 degrees C. Oviposition was examined under high and low relative humidity (RH) regimes while egg hatch was determined at six RH levels, each maintained in a separate controlled growth chamber set at a constant temperature (25 degrees C). Whilst RH had no influence on oviposition, eggs were highly susceptible to aridity, and continuous exposure to relative humidity below 63% for more than three days was wholly lethal at 25 degrees C. Optimum egg hatch occurred at RH between 85 and 95% for up to 12 days. The effect of day length on oviposition and subsequent egg hatch was investigated under two photoperiod regimes. Neither oviposition nor subsequent egg hatch was influenced by photoperiod. The knowledge obtained will be useful for mass rearing as well as field release programmes for L. bethae.     

Effect of temperature and humidity on development, survival and oviposition in laboratory populations of Eriworm, Philosamia ricini (Boisduval) (Lepidoptera Saturniidae)

Experiments were conducted on laboratory populations of Eriworm, Philosamia ricini Boisduval to study the effect of temperature and humidity on development, growth, survival and oviposition. Experiments were performed at four different temperatures (22 +/- 2 degrees C, 26 +/- 2 degrees C, 28 +/- 2 degrees C and 34 +/- 1 degrees C) each with three different humidities (50%, 70% and 90% relative humidity). Shortest developmental period (42 days) was observed in 28 +/- 2 degrees C and 70% RH. Longest developmental period was (63.6 days) observed in 22 +/- 2 degrees C at 50% RH. Highest larval weight (9.1 g) was found in 28 +/- 2 degrees C at 70% RH. Best pupal weight was observed in 26 +/- 2 degrees C at 70% RH. Weight of silk material was found to be maximum in 26 +/- 2 degrees C at 70% RH. Survival was best in 28 +/- 2 degrees C and 26 +/- 2 degrees C at 70% RH. Oviposition was found to be highest in 28 +/- 2 degrees C at 70% RH.     

嗜卷书虱实验种群生命表的研究

在不同温度和湿度条件下对嗜卷书虱进行饲养,分别组建春实验种群特定年龄和特定时间生命表,并应用Morris模式及SWeibull频数分布以探讨温、湿度与嗜卷书虱种群数量变动的关系。结果表明,温、湿度对存活率的作用是影响该实验种群趋势指数（I）值最重要的因子,在适宜温、湿度条件下,种群存活曲线属DeeveyⅠ型,而在不太适宜条件下则属DeeveyⅢ型,理论上30.63℃时周限增长率（λ）最大,达1.0628倍／天,该虫发育和繁殖的最适温区为28-30℃,最适相对湿度在80％左右。     

Sprays of emulsifiable Beauveria bassiana formulation are ovicidal towards Tetranychus urticae (Acari: Tetranychidae) at various regimes of temperature and humidity

Aerial conidia of Beauveria bassiana in an emulsifiable formulation germinated by >95% after 24 h exposure to the regimes of 20, 25 and 30 degrees C with 51%, 74% and 95% RH. Ovicidal activities of the formulation towards two-spotted spider mite, Tetranychus urticae, were assayed at the concentrations of 0, 18, 160 and 693 conidia mm(-2) sprayed separately onto fava bean leaves including 39 (25-76) eggs per capita. All the sprayed eggs on the leaves were directly exposed to the different regimes for hatch after 24 h maintenance in covered Petri dishes. Generally, hatched proportions increased over post-spray days and decreased with the elevated fungal concentrations; no more eggs hatched from day 9 or 10 onwards. Based on the counts of the hatched/non-hatched eggs in the different regimes, the final egg mortalities were 15.0-40.4%, 48.9-66.6% and 62.9-87.5% at the low, medium and high concentrations, respectively, but only 5.6-11.3% in blank controls. The RH effect on the fungal action was significant at 20 and 25 degrees C but not at 30 degrees C whereas the effect of temperature was significant at 51% and 74% RH but not at 95% RH. Probit analysis of the egg mortalities versus the fungal sprays generated median lethal concentrations (LC(50)) of 65-320 conidia mm(-2) at all the regimes, and of only 65-78 conidia mm(-2) at 25-30 degrees C with 74-95% RH. The results highlight ovicidal activities of the emulsifiable formulation against the mite species at the tested regimes and its potential use in spider mite control.