Effects of different high constant and alternating temperatures on the development and prey consumption of Dicyphus tamaninii Wagner (Heteroptera, Miridae) with Aphis gossypii Glover (Homoptera, Aphididae) as prey

The present work aimed to study the effects of high constant and alternating temperatures on the development and prey consumption by Dicyphus tamaninii Wagner (Het., Miridae) with Aphis gossypii Glover (Hom., Aphididae) as prey.Results showed that the predator was able to successfully develop and reach the adult stage, on average, after 20.1 () and 20.6 () days at a temperature of 30 ± 1 °C with A. gossypii as prey. On the other hand, it was not able to develop at 35 ± 1 °C, here all N₁ instars used at the beginning of the experiments had died even before moulting to N₂ instar. At alternating temperatures of 25/15 ± 1 °C, the predator reached the adult stage 23.7 () and 23.5 () days after egg hatching, whereas when the temperatures were increased to 35/22 ± 1 °C, it took a significantly shorter period: 20.6 () and 20.9 () days. In general, the highest mortality occurred during the first two nymphal instars. The total percentage mortality during development from N₁ to adult stage was 30 % and 100 % at the constant temperatures 30 ± 1 °C and 35 ± 1 °C, respectively. At the alternating temperatures of 25/15 ± 1 °C, it was lowest with 16.5 %, while at 35/22 ± 1 °C, it was 20 %.The results of the experiments on prey consumption showed that an individual D. tamaninii consumed during its development to adult stage at 30 ± 1 °C an average of 442.2 (), 433.6 () aphids. At the constant temperature of 35 ± 1 °C, the average daily prey consumption started with 4 aphids and decreased continuously till it approached nil on the 9th day, where all predatory nymphs died. At the alternating temperatures of 25/15 ± 1 °C, the total prey consumption during development was, on average, 359.3 () and 297.0 () aphids, while at 35/22 ± 1 °C it was 348.5 () and 334.0 () aphids. The effect of the four temperatures on the prey consumption by D. tamaninii during the first 10 days after emergence was also studied. At a constant temperature of 30 ± 1 °C, a total of 446.4 () and 372.0 () aphids were consumed, compared to 40.6 () and 39.0 () at 35 ± 1 °C. At alternating temperatures of 25/15 ± 1 °C, the predatory adult consumed, on average, a total of 267.0 () and 207.0 () aphids. Increasing the temperature to 35/22 ± 1 °C resulted in a higher prey consumption by the adult predator, reaching 351.5 () and 267.7 () aphids over the same period.In conclusion, results indicated that D. tamaninii is a promising predator of the melon aphid at a temperature spectrum ranging from 15 ± 1 °C up to 35 ± 1 °C.     

Conjugation of δ-endotoxin from Bacillus thuringiensis with abamectin of Streptomyces avermitilis as a new type of biocide, GCSC-BtA, for control of agricultural insect pests

Conjugation of -endotoxin from Bacillus thuringiensis with abamectin, a toxin of Streptomyces avermitilis, was carried out to form a new type of biocide, GCSC-BtA based on Germany-China Scientific Cooperation research, for the control of agricultural insect pests. The strategy for biochemical linkage was designed by conjugating an amino group in B.t. protoxin with a carboxyl group in carboxylated abamectin under the treatment of conjugator EDC [1-Ethyl-3-(3-dimethylaminopropyl carbodiimide Hydrochloride)]. The formation of B.t. protoxin was processed by solubilizing B.t. crystal in 25mM dithiothreitol (DTT) at 37°C for 2h. The carboxylated abamectin was formed by carboxylating the NaH-activated abamectin with 10mg/ml butyric anhydride at 111°C in a water-circumfluent condensation device for 2h. The conjugating reaction, consisting of 5mg/ml B.t. protoxin, 10mg/ml carboxylated abamectin and 19.17mg/ml EDC, was successfully conducted at room temperature for 24h. Significant differences were found between pure abamectin, carboxylated abamectin and the conjugated BtA by means of UV-photo absorptions recorded at wavelengths 354, 438, 518, 600nm (P<0.01). LT₅₀ of the conjugated GCSC-BtA to the 3^rd instar larvae of Plutella xylostella (L.) (Lep., Plutellidae) was 35.27 g a.i./ml, about 62% and 76% of that caused by the B.t. protoxin and the caxboxylated abamectin, respectively. The conjugated GCSC-BtA caused 87.14% mortalities in larvae of P. xylostella, 93.75% in adult Myzus persicae (Sulzer) (Hom., Aphididae) and 89.33% in adult Phyllotreta vittata Fabricius (Col., Chrysomelidae) as compared to 48.33% by the B.t. crystal only in P. xylostella. The symptoms caused by conjugated GCSC-BtA in the 3^rd instar of P. xylostella were black color in the head part and white-yellow in the abdomen of dead larvae, which differed from the black color or the white-yellow all along the body caused by either the B.t. crystal or the abamectin, respectively. It was concluded that the conjugated GCSC-BtA biocide had a broader host spectrum and a faster killing speed than either the B.t. crystal or abamectin alone for the control of agricultural pests.     

Investigations on side-effects of the mixed biocide GCSC-BtA on different predators of Plutella xylostella (L.) (Lep., Plutellidae) in southeastern China

The present paper deals with laboratory studies on side-effects of the mixed biocide GCSC-BtA on Plutella xylostella (L.) (Lep., Plutellidae) and its predators, e.?g. Amblyseius longispinosus (Evans) (Acari, Phytoseiidae), Erigonidium graminicola (Sundvall) (Araneae, Linyphiidae), Orius similis Zheng (Het., Anthocoridae) and Coccinella septempunctata L.(Col., Coccinellidae), in comparison to the commercial insecticides, e.?g. Abamectin, Tebufenozide, Dichlorvos, Cartap and Lambda-cyhalothrin. The results showed that GCSC-BtA was highly toxic to the 3^rd instar of P. xylostella with 91.18?% mortality, followed by Cartap with 84.38?%, Abamectin with 78.00?%, Tebufenozide with 75.57?%, Lambda-cyhalothrin with 63.75?% and Dichlorvos with 50.86?% mortality. On the other hand, GCSC-BtA was found to be comparatively less toxic to the predators, causing 31.11?%, 13.33?%, 11.54?% and 6.00?% mortalities in A. longispinosus, E. graminicola, O. similis and C. septempunctata, respectively. For comparison, the mortalities recorded for Abamectin, Tebufenozide, Dichlorvos, Cartap, Lambda-cyhalothrin were 72.94?%, 55.55?%, 70.00?%, 53.26?% and 98.85?% in A. longispinosus, 46.51?%, 55.10?%, 60.00?%, 46.00?% and 73.68?% in E. graminicola, 22.00?%, 16.00?%, 35.71?%, 26.78?% and 81.03?% in O. similis, 15.55?%, 19.64?%, 28.00?%, 16.66?% and 41.79?% in C. septempunctata, respectively. Cluster analysis was introduced to group the mortalities caused by the treatments into three toxicity groups with the distance of D?=?4.1. The 1^st group consisted of GCSC-BtA characterized with low toxicity to all the predators tested with 15.49?% mortality on average (highest 31.11?% and lowest 6.00?%). The 2^nd group consisted of Abamectin, Tebufenozide, Dichlorvos and Cartap with moderate toxicity to the predators with 39.96?% mortality on average. The 3^rd group included Lambda-cyhalothrin with high toxicity to the predators with 73.83?% mortality on average (highest 98.85?% and lowest 41.70?%). The susceptibility of the pest and its predators to GCSC-BtA and the insecticides is discussed. GCSC-BtA as a biological control agent is recommended for use in the integrated pests control programs in the vegetable fields.     

Entwicklung, Fraßleistung und Beutepräferenz vonHippodamia convergens Guer.-Men. (Col., Coccinellidae) mitThrips tabaci Lind. (Thys., Thripidae) sowie zwei Aphidenarten als Beute

Thrips tabaci Lind. is very difficult to control and thus one of the most important pests of leek in Europe. As an alternative to insecticides biological control may be carried out by making use of beneficial insects, the Coccinellidae being one of the most important predatory families. In the present study laboratory trials were carried out withHippodamia convergens Guer.-Men., one of the polyphagous representatives of the lady birds, to figure out the feeding activity, development and prey preference ofH. convergens against the onion thrips in comparison with two aphid species. H. convergens developed fully when fed exclusivelyT. tabaci larvae, although mortality was considerably higher and development took much longer. When fed thrips the complete development lasted 29,8 days on an average, the mortality reaching 88%. When offeredAcyrthosiphon pisum (Harris)H. convergens took only 24 days for development with a mortality of only 16%. Above all, the fourth larval instar and the pupa suffered from a very high mortality, reaching 45 and 50% respectively. WithA. pisum as a prey mortality decreased to only 6%. The duration of the pupal development was not affected by the prey species. The feeding activity ofH. convergens increased significantly during the development. The larvae of the second and fourth instar predated 28 and 170 thrips larvae respectively per day as a maximum. The adults achieved the highest feeding activity, predating more than 300 thrips larvae in 24 hours. When adding up the number of prey individuals per day for each developmental instar, the L₂ larvae predated more than 90 and the L₄ larvae more than 1000 thrips larvae. When offered thrips larvae andMyzus persicae (Sulz.) simultaneously, there was an increasing prey preference during the development ofH. convergens from first larval instar to adult. As to the last instars there was 20–25% less predation of thrips larvae compared to the aphids during 24 hours.     

捕食性天敌黑纹透翅花蝽的生物学特性

以榕母管蓟马为猎物,研究了黑纹透翅花蝽(Montandoniola moraguesi)的历期及捕食量.该蝽发育历经卵、1～5龄若虫、成虫;在15～35℃,发育历期随温度升高而呈逻辑斯蒂递减;卵期发育起点温度为7.9℃,有效积温为107.4日度;若虫期发育起点温度为10.0℃,有效积温为298.0日度.该蝽未成熟期在15℃及35℃时的死亡率较20～25℃时高.在25℃下,黑纹透翅花蝽各龄若虫及雌成虫对蓟马卵的日捕食量为1.8～10.4粒/头,对蓟马成虫的日捕食量为1.1～2.6蓟马/头.该蝽雌成虫对蓟马卵、一龄若虫的捕食量无显著差异,平均每雌捕食10.2～10.4粒(头)/d;对蓟马二龄若虫、"蛹"、成虫之间的捕食量亦相似(2.6～3.7头/d).     

Survey on the distribution of the Horse Chestnut ScalePulvinaria regalisCanard (Hom., Coccidae) in Germany in the years 1996 to 1998

In the present study, the distribution of the Horse Chestnut Scale insectPulvinaria regalis Canard in Germany in the years 1996 to 1998 and tendencies in the variation of infestation levels during the past three years were investigated by a survey. A questionnaire was sent to the offices for green areas and environmental affairs of 121 cities in Germany with a population exceeding 75.000 citizens. Additional observations by the authors were also taken into consideration. A comparison to data from 1995 was conducted. In the year 1998, this arboricultural pest occurred in 34 cities (15 in 1995) and could be found in the areas of the Rhineland and the Ruhr-Valley, from Bonn in the south up to Münster (Westphalia) in the north and from Aachen in the west to Hagen and Dortmund in the east.P. regalis could also be detected in Offenbach and Frankfurt a. M., It also occurred southward along the rivers Rhine and Neckar in the cities of Mainz, Ludwigshafen, Freiburg and Stuttgart. The most southern point whereP. regalis was detected in July 1998 was Zürich in Switzerland. The first occurrence of the 19 new observed infestations withP. regalis took place in six instances before 1995, eight in 1995, three in 1996, and one each in 1997 and 1998. The investigations about tendencies in the variation of infestation levels revealed a decrease in scale numbers only in the cities where Horse Chestnut Scales have been observed first in Germany. On the other hand, almost every place located further away from these infestation sites showed a population increase ofP. regalis. Constant infestation levels over the past three years could be found in only two cities. In most cases lime, maple and horse chestnut trees were the host plants of this scale insect.     

Survey on the distribution of the Horse Chestnut ScalePulvinaria regalisCanard (Hom., Coccidae) in Germany in the years 1996 to 1998

In the present study, the distribution of the Horse Chestnut Scale insectPulvinaria regalis Canard in Germany in the years 1996 to 1998 and tendencies in the variation of infestation levels during the past three years were investigated by a survey. A questionnaire was sent to the offices for green areas and environmental affairs of 121 cities in Germany with a population exceeding 75.000 citizens. Additional observations by the authors were also taken into consideration. A comparison to data from 1995 was conducted. In the year 1998, this arboricultural pest occurred in 34 cities (15 in 1995) and could be found in the areas of the Rhineland and the Ruhr-Valley, from Bonn in the south up to Münster (Westphalia) in the north and from Aachen in the west to Hagen and Dortmund in the east.P. regalis could also be detected in Offenbach and Frankfurt a. M., It also occurred southward along the rivers Rhine and Neckar in the cities of Mainz, Ludwigshafen, Freiburg and Stuttgart. The most southern point whereP. regalis was detected in July 1998 was Zürich in Switzerland. The first occurrence of the 19 new observed infestations withP. regalis took place in six instances before 1995, eight in 1995, three in 1996, and one each in 1997 and 1998. The investigations about tendencies in the variation of infestation levels revealed a decrease in scale numbers only in the cities where Horse Chestnut Scales have been observed first in Germany. On the other hand, almost every place located further away from these infestation sites showed a population increase ofP. regalis. Constant infestation levels over the past three years could be found in only two cities. In most cases lime, maple and horse chestnut trees were the host plants of this scale insect.     

Laboratory studies on the effect of temperature and humidity on the life table of the whitefly,Aleurotuberculatus takahashi David & Subramaniam (Hom., Aleyrodidae) from southeastern China

The present paper deals with developmental duration, emergence, longevity and fecundity ofAleurotuberculatus takabashi David & Subramaniam at different temperatures and humidity levels. The developmental time from egg to adult was 81.8, 56.9, 39.6, 29.9, 20.6 days at 15±1, 20±1, 25±1, 30±1, 35±1°C under constant relative humidity (RH) of 70±5%, respectively. At 25±1°C, the total developmental time was slightly affected by humidity, ranging from 46.4 days at 40±5% RH to 39.2 days at 90±5% RH. The developmental threshold and the thermal constant for the stage from egg to adult were 10.1°C and 542.8 day-degrees. It was estimated that the whitefly has about 10 generations a year in Fuzhou region in southeastern China. Lowest mortality rates of 12.4% for the egg, 6.8% for the nymph and 3.1% for the puparium were obtained at 15±1°C, while they were highest with 92.1% for the egg, 48.2% for the nymph and 36.3% for the puparium at 35±1°C. The mortality rates were slightly affected by humidity, ranging from 17.6% at 40±5% RH to 27.9% at 90±5% RH for the egg, 11.2% at 40±5% RH to 19.6% at 90±5% RH for the nymph, and 6.4% at 40±5% RH to 11.6% at 90±5% RH for the puparium. The emergence rate of adults decreased as temperature increased, ranging from 89.1% at 15±1°C to 21.5% at 35±1°C, so did the longevity of adults, ranging from 9.6 days at 15±1°C to 2.9 days at 35±1°C. The number of eggs per female was significantly affected by temperature (P.01), valuing 29.4 eggs per female at 15±1°C, 36.7 at 20±1°C, 52.4 at 25±1°C, 42.9 at 30±1°C, and 6.1 at 35±1°C. The optimal temperature for reproduction was about 25°C.     

生物杀虫剂BtA对结球甘蓝地害虫及其捕食性天敌生态位变动的影响

2001年在中国东南部福州地区进行生物杀虫剂BtA和化学杀虫剂灭多威对结球甘蓝地捕食性天敌及其猎物对象害虫空间生态位宽度和重叠的影响的研究。研究对象捕食性天敌包括七星瓢虫(Coccinella septempunctata L．)和草间小黑蛛[Erigonidium graminicola(Sundvall)]，猎物对象害虫包括小菜蛾[Plutella xylostella(L．)]、菜粉蝶[Pieris rapae(L.)]、菜蚜[Brevicoryne brassicae(L．)]、斑潜蝇(Liriomyza satlvae Blanch．)、黄条跳甲(Phyllotreta vittata Fabric．)。研究结果表明。天敌害虫比在BtA处理区为0．395O，在灭多威处理区为0．2018．说明BtA对被测捕食性天敌的影响小于灭多威。捕食性天敌的空间生态位宽度变动范围为2．81～4．44，BtA和灭多威对捕食性天敌空间生态位宽度变化影响不显著。被测害虫空间生态位宽度变动范围为1．42～5．86，BtA和灭多威对被测害虫空间生态位宽度变化影响极显著。这种变化改变了捕食性天敌与害虫之间在空间范围内的数量关系，进而影响到它们之间的空间生态位重叠。天敌和害虫之间空间生态位重叠研究表明，重叠值的变动范围为O．10％～87．78％。在BtA处理区，草间小黑蛛与小菜蛾的空间生态位重叠为78．46％，七星瓢虫与菜蚜的空间生态位重叠为58．33％，而在灭多威处理区，以上两个指标分别为38．71％和18．59％，说明灭多威显著地降低了天敌与害虫之间空间生态位的重叠，影响到天敌对害虫的捕食能力。文中对BtA和灭多威对捕食性天敌及其猎物对象害虫空间生态位变化所引起的天敌-害虫数量变动进行了讨论。     

多位点生物杀虫毒素BtA形成的HPLC分析

 基于多位点生物杀虫毒素理论和生物耦合技术，研制生物杀虫毒素BtA，为新生物农药的开发提供了一种新思路、新方法和新手段。将苏云金芽孢杆菌（B.t.）晶体进行酶解改造，形成带末端氨基的原毒素；将阿维菌素的羟基进行激活、衍生化，形成带羧基的阿维菌素衍生物（Abamectin-COONa）；再利用氨基-羧基偶联剂（EDC）进行两种生物毒素的生物耦合。利用反相液相色谱（HPLC）检测不同反应时间的BtA生物耦合体系，以确定生物耦合反应的发生；通过反应底物两两组合的分析比较，识别生物耦合产物BtA生成的色谱特征，分析生物耦合产物---多位点生物杀虫毒素BtA的产生过程。