飞虱虫疠霉液培菌丝的凝胶化及其杀蚜活性

用丙烯酰胺淀粉凝胶包埋飞虱虫疠霉（Pandora delphacis)液培菌丝,制成含营养和不含营养的虫霉凝胶,并测试其产孢能力及对桃蚜（Myzus persicae)的侵染力。经持续9d产孢观察。相同菌丝量条件下,含营养的虫霉凝胶的累计产了解量（1910.9个/mm^2)为不含营养的虫霉凝胶的3.14倍（608.5个/mm^2)和对照（纯液培菌丝）的4.69倍（387.5个/mm^2)。用虫霉凝胶的“孢子浴”接种桃蚜居群（成蚜与不同龄期若蚜的混合）,在2.23个/mm^2的剂量下,接种后第7d的死亡率达82.3%。结果表明,丙烯酰胺淀粉凝胶作为载体材料,与飞虱虫疠霉的基本生物学特性相容,对虫霉的剂型化具有重要意义。     

飞虱虫疠霉分生孢子在桃蚜体壁上的附着与入侵

用飞虱虫疠霉（Pandora delphacis)初级分生孢子接种桃蚜（Myzus persicae),24h内定时取样,在扫描电镜下观察孢子的萌发及其对寄主体壁的入侵。结果表明,附着到蚜体表面的孢子在4h内有30－40％已萌发产生芽管,少数是呈叉状分枝的营养生长型芽管。且侵染性芽管的孢子部分孢入体壁蜡质层中,显示孢子有分泌物产生并作用于寄主体壁。接种10h内,侵染性芽管通过顶端膨大的附着胞或直接穿透入寄主体壁。到24h时,产生侵染性芽管的孢子全部侵入寄主体内,寄主体表仅留下少数未萌发的孢子或营养生长型芽管。初级分生孢子在蚜体表面很少产生次级分生孢子,说明桃蚜是适合该菌侵染的寄主。陷入寄主体壁的孢子不因若蚜蜕皮而被去掉,表明该菌对成蚜和若蚜都具有侵染力。     

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。     

飞虱虫疠霉液培菌丝的凝胶化及其杀蚜活性*

用丙烯酰胺淀粉凝胶包埋飞虱虫疠霉(Pandora delphacis)液培菌丝,制成含营养和不含营养的虫霉凝胶,并测试其产孢能力及对桃蚜(Myzus persicae)的侵染力。经持续9 d产孢观察,相同菌丝量条件下,含营养的虫霉凝胶的累计产孢量(1910.9 个/mm2）为不含营养的虫霉凝胶的3.14倍（608.5个/mm2）和对照（纯液培菌丝）的4.69倍（387.5个/mm2）。用虫霉凝胶的“孢子浴”接种桃蚜居群（成蚜与不同龄期若蚜的混合）,在2.23个/mm2的剂量下,接种后第7 d的死亡率达82.3%。结果表明,丙烯酰胺淀粉凝胶作为载体材料,与飞虱虫疠霉的基本生物学特性相容,对虫霉的剂型化具有重要意义     

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。     

飞虱虫疠霉分生孢子在不同温湿度组合条件下的存活率

用荧光染色法研究了不同温度（10－30℃）和湿度（51－100％RH）组合条件下飞虱虫疠霉Pandora delphacis分生孢子的存活率。在无放回抽样观察中,孢子弹射后第24h的存活率在51％、74％、85％、90％、95％和100％RH与不同温度的组合中分别为42－81％、69－89％、70－95％、67－100％、76－100％和56－100％。存放4个月后,不同温度下的孢子存活率在51％、74％、85％和90％RH下分别为55－74％、52％－87％、38－73％和1－65％。而在≥95％RH下孢子存活率24h后锐减,至第7d几乎全部失活。以上结果表明,弹射后的飞虱虫疠霉孢子在头24h的存活易受低湿影响,但存活下来的孢子能继续在低湿下存活较久;饱和或接近饱和的高湿度最不利孢子长久存活。     

飞虱虫疠霉分生孢子在桃蚜体壁上的附着与入侵*

用飞虱虫疠霉(Pandora delphacis)初级分生孢子接种桃蚜(Myzus persicae),24 h内定时取样,在扫描电镜下观察孢子的萌发及其对寄主体壁的入侵。结果表明,附着到蚜体表面的孢子在4 h内有30~40%已萌发产生芽管,其中多数为侵染性芽管,少数是呈叉状分枝的营养生长型芽管。具侵染性芽管的孢子部分陷入体壁蜡质层中,显示孢子有分泌物产生并作用于寄主体壁。接种10 h内,侵染性芽管通过顶端膨大的附着胞或直接穿透侵入寄主体壁。到24 h时,产生侵染性芽管的孢子全部侵入寄主体内,寄主体表仅留下少数未萌发的孢子或营养生长型芽管。初级分生孢子在蚜体表面很少产生次级分生孢子,说明桃蚜是适合该菌侵染的寄主。陷入寄主体壁的孢子不因若蚜蜕皮而被去掉,表明该菌对成蚜和若蚜都具有侵染力。     

干燥与温度对飞虱虫疠霉凝胶化菌丝产孢特性的影响

The entomophthoraceous fungus, Pandora delphacis, is a microbial agent highly potential for control of sucking\|type insects.In this study,effort was made of gelatinizing the mycelia of the isolate F95129 from submerged culture using polyacrylamide\|starch gel pwder and sodium alginate.The resulting film\|like gel of the mycelia sporulated very well,indicating that the materials used for gelatinization of the mycelia was biologically compatible with P.delphacis. Then,the gelatinized mycelia were slowly dr…     

飞虱虫疠霉分生孢子在不同温湿度组合条件下的存活率*

用荧光染色法研究了不同温度（１０～３０℃）和湿度（５１～１００％ＲＨ）组合条件下飞虱虫疠 霉 Ｐａｎｄｏｒａ ｄｅｌｐｈａｃｉｓ分生孢子的存活率。在无放回抽样观察中,孢子弹射后第２４ ｈ的存活 率在５１％、７４％、８５％、９０％、９５％和１００％ＲＨ与不同温度的组合中分别为４２～８１％、６９～８９％、７０～ ９５％、 ６７～１００％、 ７６～１００％和 ５６～１００％。存放４个月后,不同温度下的孢子存活率在 ５１％、 ７４％、 ８５％和 ９０％ＲＨ下分别为 ５５～７４％、 ５２～８７％、 ３８～７３％和 １～６５％。而在≥９５％ ＲＨ下孢子存活率 ２４ｈ 后锐减,至第７ ｄ几乎全部失活。以上结果表明,弹射后的飞虱虫疠霉孢子在头２４ ｈ的存活 易受低湿影响,但存活下来的孢子能继续在低湿下存活较久;饱和或接近饱和的高湿度最不 利孢子长久存活。     

努利虫疠霉感染桃蚜过程的扫描电镜观察

利用扫描电镜观察了努利虫疠霉Pandora nouryi (Remaudière & Hennebert) Humber初生分生孢子接种桃蚜Myzus persicae (Sulzer)后孢子萌发、入侵以及菌体突破虫体的整个侵染过程。结果表明：附着于虫体表面的初生分生孢子在3～5 h后即有60%以上的萌发率,萌发的孢子形成芽管或产生球形或棍棒状的附着胞;12 h后大部分孢子均已萌发,并成功入侵寄主虫体;接种60 h后,呈掌状分枝的假根首先从桃蚜胸部的腹面突破虫体长出体外,明显区别于新蚜虫疠霉Pandora neoaphidis (Remaudière & Hennebert) Humber假根突破虫体的位置;假囊状体不多见,且仅分布于蚜虫身体两侧,这可在一定程度上解释努利虫疠霉产孢对湿度条件要求较高的生物学现象。     

适合飞虱虫疠霉菌丝生产的液体培养基组分及发酵条件

蚜虫、飞虱、叶蝉等是威胁农业生产的刺吸式口器害虫,长期以来依赖化学农药防治,严重影响农产品的安全性和农业生态环境.探讨这类害虫的生物防治途径,减轻农产品化学农药的残留污染,一直受到国内外学者的关注.虫霉(En-tomophthorales)的许多种类具有优异的诱病杀虫能力,尤其通过主动弹射孢子而在害虫种群中高强度流行的特征,可在短期内迅速压低虫口密度,是极其重要的杀虫微生物资源[1～3].     

New use of broomcorn millets for production of granular cultures of aphid-pathogenic fungus Pandora neoaphidis for high sporulation potential and infectivity to Myzus persicae

Glutinous broomcorn millets from the crop Panicum miliaceum were first used as substrate to produce granular cultures of Pandora neoaphidis, an obligate fungal pathogen specific to aphids. Carrying a water content of 36.5% after being steamed in a regular autoclaving procedure, millet grains of each 15 g (dry weight) in a 100-ml flask were mixed with 3 ml modified Sabouraud dextrose broth containing half a mashed colony of P. neoaphidis grown on egg yolk milk agar and then incubated at 20 degrees C and a light/dark cycle of 12 h/12 h for 21 days. Based on individually monitoring conidial production potential of 20 millet grains sampled from an arbitrarily taken flask at 3-day intervals, the millet cultures incubated for 6-15 days were capable of producing 16.8-23.4 x 10(4) conidia per millet grain with conidial ejection lasting for up to 6 days. The cultured millet grains individually produced significantly more conidia than apterous adults of Myzus persicae killed by P. neoaphidis (8.4 x 10(4) conidia per cadaver) and sporulated twice longer. The modeling of time-dose-mortality data from bioassays on M. persicae apterae exposed to conidial showers from the cultured millet grains and the mycelial mats produced in liquid culture resulted in similar estimates of LC(50) (millets: 21.4, 7.3, and 4.9 conidia mm(-2) on days 5-7 after exposure; mycelial mats: 22.1, 10.6, and 7.7 conidia mm(-2)) although the LT(50) estimated at a given conidial concentration was slightly smaller for the millet cultures than for the mycelial mats. This indicates that the millet grains cultured with P. neoaphidis produced conidia as infective as or slightly more infective to M. persicae than those from the mycelial mats. Based on the sporulation potential, infectivity, and ease and cost of the millet cultures, the method developed in this study highly improved in vitro cultures of P. neoaphidis and may adapt to culturing other entomophthoralean fungi for microbial control of insect pests.     

Factors affecting sporulation and germination of Pandora nouryi (Entomophthorales: Entomophthoraecae), a pathogen of Myzus persicae (Homoptera: Aphididae)

Pandora nouryi discharged large numbers of primary conidia between 8 and 25°C from cadavers on the surface of water-agar. At 8°C conidial discharge lasted for 120 h, but most conidia were produced within 48 h when temperature was >15°C. Saturated humidity alone was not enough to allow for sporulation to occur freely and where RH?<?95%, no conidia were discharged. Light did not affect the pattern of conidial production nor the total number of conidia. Germination percentages of conidia on the surface of water-agar were 40 and 66% at 8 and 30°C, respectively, and were significantly lower than that at 15–25°C where germination was >95%. Conidia on leaves germinated well when RH?>?74%, while no germination occurred when RH?<?100% on cover slips. All eight insecticides tested entirely inhibited conidial germination at recommended doses (R), in particular, both the organophosphorus pesticides Lorsben (chlorpyrifos) and the organochlorine pesticides Thiodan (endosulfan) completely inhibited conidial germination even at 0.2R dose.     

Sporulation,storage and infectivity of obligate aphid pathogen Pandora nouryi grown on novel granules of broomcorn millet and polymer gel

Aims: Producing granular cultures of obligate aphid pathogen Pandora nouryi for improved sporulation and storage. Methods and Results: Small millet–gel granules were made of the mixtures of 80–95% millet powder with 5–20% polymer gel (polyacrylamide, polyacrylate or acrylate‐acrylamide copolymer) and inoculated with mycelia at 30 mg biomass g^?1 dry granules plus 87·5% water, followed by static incubation at 20°C for 4–12 days. The fungus grew well on 12 preparations but best on that including 10% copolymer. An 8‐day culture of this preparation discharged maximally 58·5 × 10⁴ conidia mg^?1 granule at 100% RH and was capable of ejecting conidia at the nonsaturated regimes of 86–97% RH. During storage at 6°C, granular cultures with >85% water content had twofold longevity (120 days) and half‐decline period (34–36 days) of those stored at room temperature. The steadily high water content preserved the cultures better than that decreasing at 6°C. However, conidia from 70‐day‐stored granules were less infective to Myzus persicae nymphs than those from fresh ones based on their LC₅₀s. Conclusions: The millet–gel granules had higher sporulation capacity than reported Pandora cultures and a capability of spore discharge at nonsaturated humidity. Significance and Impact of the Study: The granular cultures are more useful for aphid control.     

蚜虫性信息素对桃园蚜虫的引诱作用

将从荆芥Nepeta cataria L.中提取的纯度为96%的荆芥内酯和通过二异丁基铝还原提取的荆芥内酯得到的纯度为67%荆芥醇,配成浓度为5%的不同比例的己烷溶液,于1995年10月19～28日在北京大兴县南郊农场的桃园进行了引诱蚜虫的试验。各种比例的性信息素诱捕器均能引诱到桃蚜Myzus persicae (Sulzer)雄蚜、桃粉大尾蚜Hyaloptera amygdali Blanchard雄蚜以及少量的桃蚜产雌性母;荆芥醇和荆芥内酯的比例为1∶1时引诱桃蚜雄蚜的效果最好;单一组分的荆芥醇引诱桃粉大尾蚜雄蚜的效果最好。     

不同寄主及地理来源的16株绿僵菌对桃蚜的毒力比较

害虫生防真菌绿僵菌的不同种及变种被广泛应用于害虫微生物防治,但罕见以蚜虫等同翅目刺吸式害虫作为靶标。从两种绿僵菌的4个变种中精选16个不同寄主及地理来源的菌株,用喷塔接种桃蚜(Myzus persicae)无翅成蚜并在25±1℃和12L∶12D条件下饲养观察,所获生物测定数据进行时间-剂量-死亡率模型模拟分析。结果显示,高接种剂量(~1000个孢子/mm2)下7d内死亡率达67%~100%的10个菌株均为金龟子绿僵菌Metarhiziumanisopliae(Ma)及其金龟子变种M.anisopliaevar.anisopliae(Maa);而高剂量处理下仅感染致死个别或少数蚜虫的菌株包括金龟子绿僵菌及其金龟子变种、大孢变种M.anisopliaevar.majus和蝗变种M.anisopliaevar.acridum以及黄绿绿僵菌小孢变种M.flavoviridevar.minus。杀蚜活性优异的2个菌株分别为Ma 456和Maa 3332,接种后第4天的LC50分别为113和260个孢子/mm2,第5天为32和43个孢子/mm2,第6天为17和26个孢子/mm2,第7天仅11.4和19.9个孢子/mm2。这两个菌株具有用于蚜虫微生物防治的良好开发潜力。