Activity ofBacillus thuringiensis isolates on the corn borers,chilo agamemnon Bles. (Crambidae) andOstrinia nubilalis Hbn. (pyraustidae)

The potential activity of different varieties ofBacillus thuringiensis was evaluated against the second instar larvae of the two lepidopterous corn borersChilo agamemnon andOstrinia nubilalis. Data on the LC₅₀, slopes, 95% confidence limits and potencies of the tested varieties were determined. WithO. nubilalis, Dipel 2X (Bacillus thuringiensis. var.kurstaki HD-1) was the most potent and the LC₅₀ was 2.68 μg/g diet. The LC₅₀ for other varieties ranged between 3.12 and 31.95 μg/g. In the case ofC. agamemnon, the lowest LC₅₀ was also determined with Dipel 2X being 3.68 μg/g diet; this ranged between 6.2–15.11 μg/g for other tested varieties.     

Seasonal diet of the Great Spotted Woodpecker （Picoides major） in shelterwood plantations of Wulate Qianqi County,Inner Mongolia

The feeding habits of the Great Spotted Woodpecker （Picoides major） were surveyed by field observations and trace checking from 2005 to 2007, in Wulate Qianqi County, Inner Mongolia Autonomous Region, China, during which the woodpecker performed fourteen types of foraging techniques. Pecking and hammering were most common in winter; gleaning and probing were most common at times of high food availability at the trunk and tree branches during the breeding season and in summer. The woodpecker gleans arthropods and insect larvae in the breeding season and summer, seeds and nuts mainly in the winter and pokes holes for sap-sucking in winter. The main diet consisted of arthropods and plant seeds. The diet was significantly different between seasons The Great Spotted Woodpecker primarily consumes defoliators and the food on tree trunks from March to October. The contribution of wood borers to the diet was higher in winter, lower in the breeding season and summer. The proportion of the food on ground was small in the breeding season and high in the Summer and winter.     

美国白蛾的生物防治研究

作者通过浸虫法和浸叶法分别测定了苦参碱和虫酰肼对美国白蛾3龄幼虫的室内生物活性,结果如下:苦参碱对美国白蛾3龄幼虫的毒力回归方程为y=4.043 9+0.713 1x,其致死中浓度LC50为21.915 2 mg/L,LC90为1 373.543 9 mg/L;虫酰肼对美国白蛾的毒力回归方程为y=4.431 2+0.689 1x,其致死中浓度LC50为6.689 6 mg/L,LC90为484.307 mg/L。     

Zunehmende Toleranz (LT-Werte) vonAnagasta kühniella Z. gegenBacillus thuringiensis mit dem Alter der Larvalentwicklung

Zusammenfassung Der schädigende Einfluß vonB. thuringiensis (Handelspräparat Biospore 2802) auf das erste bis sechste Larvenstadium vonAnagasta kühniella Z. wurde in bestimmten Intervallen der fortlaufenden Behandlung während 10 Tagen beobachtet. Drei bis vier Dosen (ansteigend von 1,7 × 10⁶ bis 3,5 × 10⁸ Sporen/g des Futters) wurden für jedes Stadium unter konstanten, gleichen Bedingungen getestet. Hundert Larven vom ersten und 50 Larven von jedem folgenden Stadium wurden bei jeder Behandlung und jeder Kontrolle so verwendet, daß Alter, Körpergewicht und Kopfkapselbreite nur geringfügige Unterschiede aufwiesen. Die Beziehung zwischen Sterblichkeitsprozent und der Behandlungsdauer bei einer bestimmten Dosis wurde für jedes Stadium dargestellt, wobei LT₅₀ jedem Fall bestimmt wurde. Die Ergebnisse waren:1. Die Behandlungsdauer, die eine bestimmte Mortalität auslöst, ist umgekehrt proportional der Dosis, dem Alter und dem Körpergewicht.2. Die Unterschiede in der Wirkung der Dosen auf ein bestimmtes Stadium waren während der Perioden zwischen dem dritten und sechsten Tag größer als zu deren Beginn und Ende.3. Ein Vergleich der LT₅₀ Werte der aufeinanderfolgenden Stadien zeigte eine zunehmende Toleranz gegen das Pathogen mit Entwicklung der Larven, besonders bei Erreichung des dritten und fünften Stadiums.

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Summary The detrimetal effect ofBacillus thuringiensis Berliner (commerciel preparation, Biospore 2802) on the first to sixth larval instars ofAnagasta kühniella Z. was traced at successive intervals of continuous treatment for 10 days (voluntary ingestion). Three to four doses (ranging from 1.7 × 10⁶ to 3.5 × 10⁸ viable spores/g of diet) were tested in every instar under constant, identical laboratory conditions. Fifty to 100 larvae of each instar were used for each dose and a similar number in each case for the control, being chosen with minimal difference in age, body weight and head capsule breadth. The relationship between mortality percent and time of exposure to the given doses in every instar was demonstrated and the LT₅₀ in every case was estimated. The results revealed that:1. The necessary time to initiate a definite lethal effect is reversedly proportional to dose, age and body weight.2. The differences in effect between the doses on a given instar were greater during the period between the third and sixth day of exposure than they were at its beginning or end.3. A comparison of the LT₅₀ values revealed an increasing tolerance to the pathogen with larval development, particularly by reaching the third and fifth instars.

     

Die Milbe Varroa jacobsoni Oudem., ein neuer Bienenparasit

The mite Varroa jacobsoni Oudem., a new parasite of the honey bee A view is given of the state of knowledge of the miteVarroa jacobsoni which was introduced from Eastern Asia to East and Middle Europe in younger time as an ecto-parasite of the honey bee,Apis mellifica. Especially new scientific findings given at theVarroa-Symposium in Vienna, 1977, are reported. This symposium was arranged by the Bundeslehr-und Versuchsanstalt für Bienenkunde, Lunz am See, and visited by 20 veterinarian and apidologists of 7 countries. The base lines of development and bionomy of the mite are given.V. jacobsoni lays the eggs on the bee larvae. The descendants leave the cells together with the young bees. Without bees the mites lived 5–9 days only. From a number of 10–20 mites the development of the bee larva is disturbed. In East EuropeV. jacobsoni caused high losses of bee swarms in last years. The ways of diagnosis and control are discussed. To day the bee-keeper can use a number of more or less effective preparations against the pest.

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Bundeslehr- und Versuchsanstalt für Bienenkunde A-3293 Lunz am See.     

松褐天牛肿腿蜂对松褐天牛低龄幼虫控制作用的研究

研究测定了松褐天牛肿腿蜂对松褐天牛1～3龄幼虫的控制作用,采用林间和室内罩网相结合的方法研究了2组松褐天牛肿腿蜂对松褐天牛幼虫的寄生情况.结果显示:在室内试验条件下,松褐天牛肿腿蜂产卵之前的刺蛰、补充营养取食能直接造成松褐天牛1～3龄幼虫死亡,对1、2及3龄幼虫的平均致死率分别为95.66％、85.91％、57.88％,并可产卵寄生2、3龄幼虫;林间释放2组松褐天牛肿腿蜂后,在刺蛰和补充营养取食后能有效寄生寄主的肿腿蜂雌蜂数量比例变化较大,有效肿腿蜂率最高为14.9％,最低为2.3％.松褐天牛肿腿蜂寄生行为不受寄主聚集程度的影响,但刚羽化出茧肿腿蜂雌蜂的寄生效率比经饲喂后的雌蜂高近5倍.从肿腿蜂单一个体来看,每头雌蜂补充营养取食和产卵寄生致死的松褐天牛幼虫数为2.1～7.7头.松褐天牛肿腿蜂雌蜂的补充营养习性及刺蛰、取食致死寄主行为在防治中有很重要的作用,表明该种肿腿蜂是防治松褐天牛的重要天敌,在生物防治松褐天牛幼龄幼虫上具有良好的应用前景.     

5种设施常用农药对欧洲熊蜂的毒力及残毒测定

为了合理保护和利用欧洲熊蜂,测定了5种设施常用药剂对欧洲熊蜂的毒力及残毒毒性,结果表明:噻虫嗪对欧洲熊蜂的半致死量LD50值为0.061μg/蜂,为高毒;氯虫苯甲酰胺对其半致死量LD50值为8.507μg/蜂,为中毒;藜芦碱、印楝素和苯醚甲环锉对其半致死量LD50值分别为69.936μg/蜂、109.141μg/蜂和336.094μg/蜂,均为低毒,其中苯醚甲环锉的毒性最低。残毒试验结果表明:天然植物源农药藜芦碱、印楝素对熊蜂没有残留毒性;杀菌剂苯醚甲环锉对其有轻微毒性;杀虫剂噻虫嗪、氯虫苯甲酰胺对其毒害比较明显,其中噻虫嗪在喷药5d后仍有轻微毒性。     

Vertical soil–air CO2 dynamics at the Takayama deciduous broadleaved forest AsiaFlux site

At the Takayama deciduous broadleaved forest Asiaflux site in Japan, the ecosystem carbon dynamics have been studied for more than two decades. In 2005, we installed non-dispersive infrared CO₂ sensors in the soil below the site’s flux tower to systematically study vertical soil–air CO₂ dynamics and explain the behavior of soil surface CO₂ efflux. Soil–air CO₂ concentrations measured from June 2005 through May 2006 showed sinusoidal variation, with maxima in July and minima in winter, similar to the soil CO₂ effluxes measured simultaneously using open-flow chambers. Soil–air CO₂ concentrations increased with soil depth from 5 to 50 cm: from 2,000 to 8,000 ppm in the summer and from 2,000 to 3,000 ppm in the winter under snow. Summer soil–air CO₂ concentrations were positively correlated with soil moisture on daily and weekly scales, indicating that the Oi, Oe, and A horizons, where decomposition is accelerated by high-moisture conditions, contributed substantially to CO₂ emissions. This result is consistent with the short residence time (about 2 h) of CO₂ in the soil and larger emissions in shallow soil layers based on our diffusion model. We revealed for the first time that soil–air CO₂ concentrations in winter were correlated with both snow depth and wind speed. CO₂ transfer through the snow was hundreds of times the gas diffusion rates in the soil. Our estimate of the CO₂ efflux during the snow-cover season was larger than previous estimates at TKY, and confirmed the important contribution of the snow-cover season to the site’s carbon dynamics.     

The biological effects of three insect growth regulators onCulex pipiens L

Tests were made to determine the possible juvenilizing effects of three insect growth regulators (IGRs) namely, IKI 7899, SIR 8514 and Dowco 439 on immature stages and adults ofCulex pipiens L. using the IC₅₀ values (concentration to inhibit the emergence of 50% of adults) as a criterion. The results indicated that IKI 7899 (0.00031 μg/ml) proved to be the most effective compound followed by SIR 8514 (0.0052 μ/ml) and Dowco 439 (0.029 μg/ml). Apart from lethal action, treatment of fourth larval instars with the IC₂₅ values (concentration to inhibit the emergence of 25% of adults) of the above-mentioned IGRs affected the reproductive capacity of surviving adults. Moreover, larval treatments with these compounds led to a marked prolongation in the duration of first gonotrophic cycle. There was also an increase in the proportion of survived females/males ofC. pipiens after these larval treatments.     

Effect of food,light and host instar on the egg load of the synovigenic endoparasitoid <Emphasis Type="Italic">Venturia canescens</Emphasis> (Hymenoptera: Ichneumonidae)

Laboratory experiments investigated the effect of host instar, light and food on the number of mature eggs in ovaries (egg load) of the synovigenic parasitoid Venturia canescens (Grav.) (Hymenoptera: Ichneumonidae). The wasps that developed from third or fifth instar larvae of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) were exposed to food (honey) or had no food, had access to water or not, and were reared at the photoperiod 16:8 h light:dark or in continuous darkness at 25 ± 1°C, and 60–70% relative humidity. After death, the parasitoids were dissected to remove the reproductive systems, and mature eggs in ovaries were counted. A three-way ANOVA for egg number with host instar, food and light as factors revealed that egg load varied significantly. In addition, some interactions among the three factors were also found to be significant. The maximum average number (215.80 ± 8.51) of mature eggs was found when the parasitoids developed from third instar larvae, were exposed to continuous darkness and fed with honey. In conclusion, host instar, food supplement and photoperiod could have potential for improving biological control efficacy in stores. However, further studies determining the effect of these factors on egg laying behavior and fecundity should be done.     

不同绿僵菌菌株对筛胸梳爪叩甲幼虫的毒力测定

竹林金针虫是南方竹林笋期最为重要的害虫之一,筛胸梳爪叩甲幼虫是竹林金针虫的优势种群,应用绿僵菌防治具有重要意义。测定了3株绿僵菌对筛胸梳爪叩甲幼虫的毒力,并比较了毒土法和毒饵法两种施菌方式对绿僵菌致病力的影响。结果表明,平沙绿僵菌WP08菌株和金龟子绿僵菌30104菌株对筛胸梳爪叩甲幼虫具有明显的致病效果,在30 d的试验期内,校正累计死亡率分别为90.0%和66.3%,半数致死时间（LT₅₀）分别为15.8 d和25.8 d;毒土法的校正累计死亡率略高于毒饵法,分别为60.1%和52.0%,LT₅₀分别为22.6 d和28.0 d。金龟子绿僵菌LRC112菌株对金针虫无致病力。     

黄杨绢野螟空间分布型 生物学及防治的研究

黄杨绢野螟(Diapania perspectalis Walker)在国内分布于北京、西安、上海、南京、贵阳、成都等10多个城市,危害黄杨、大叶黄杨、小叶黄杨、瓜子黄杨、雀舌黄杨、朝鲜黄杨、冬青、卫矛、匙叶黄杨等树木。据在西安调查,黄杨受害率在52-98％,冠径80cm的黄杨口密度最多高达112头/株。由于幼虫多为害新叶,且将叶片缀合在一起吐丝结巢,致使叶片,生长发育受阻。为了有效地防治此种害虫,我们于1989年9月-1990年8月,对黄杨绢野螟幼虫的空间分布型进行了调查,对其生活习性及化学防治作了进一步研究。     

Zur Kenntnis des an Korbweide schädlichenLepyrus palustris Scop. (Col. Curculionidae)

Summary Lepyrus palustris Scop., a pest of the basket-willow has in Hungary one generation in a year. The overwintered adults appear in the early spring and cause occasionally severe damages on the young shoots, especially in the southern parts of Hungary. The females lay 100–140 eggs during the months May–June on the earth surface near to the willow-stocks. The larvae enter the soil and damage outside on the main roots, which can cause severe losses mainly in the young plantations. The 4^th instar larva pupate in the soil. The young adults appear in July, the damage caused by them in the second part of the summer is not more important. The best control has been achieved applying Wofatox dust (3 per cent) against the overwintered adults at the beginning of the vegetation period.     

Effects of shelter tubes on hardwood tree establishment in western Oregon silvopastures

Honey locust (Gleditsia triacanthos), black locust (Robinia pseudoacacia), and honey mesquite (Prosopis glandulosa) are warm season forage trees with potential to efficiently share site resources with cool season pasture plants in Pacific Northwest silvopastures. Establishment of hardwood trees can be difficult, however, because of feeding damage from wildlife and livestock. This study compared establishment and growth of trees planted in 88 cm tall solid plastic shelter tubes to 88 cm tall plastic mesh tubes, used to protect trees from animal damage. Three replications were established in May 1995 for each of the three tree species on a hill pasture near Corvallis, Oregon. Initial tree survival during the first summer and winter following planting was higher in shelter tubes than in mesh tubes. At the end of the third growing season, 58% of black locust and 94% of honey locust trees in shelter tubes were still alive compared to only 14% of black locust and 47% of honey locust in mesh tubes. Few honey mesquite trees survived regardless of tube type used. Average three-year total height growth for black locust was increased by 650% and basal diameter growth by 380% within shelter tubes, while honey locust height growth was increased by 300% and diameter growth was increased by 150% compared to trees in mesh tubes. However, shelter tube trees tended to be taller relative to their diameter and had difficulty standing upright if tubes were removed. This revised version was published online in June 2006 with corrections to the Cover Date.     

海南凹鸠蛾幼虫和蛹过冷却点的测定

测定了海南凹鸠蛾1龄、4龄、5龄幼虫和蛹的过冷却点和冰点,结果表明,1龄幼虫的过冷却点和冰点分别为(-20.26±0.54)℃和(-19.03±1.29)℃,显著低于4龄幼虫和5龄幼虫和蛹;其他各虫态过冷却点顺序由低到高分别为蛹<5龄幼虫<4龄幼虫,冰点各虫态由低到高顺序为蛹<4龄幼虫<5龄幼虫。4龄幼虫与5龄幼虫过冷却点差异不显著,但其冰点差异显著。并在此基础上分析了海南凹鸠蛾在我国的适生性区域。     

Zur Wirkung von Bacillus thuringiensis var. israelensis auf die Larven der Stechmücke Culex pipiens molestus

Laboratory infectivity tests were undertaken to investigate the pathogenicity of “Bactimos” (a new commerical bacterial biocide) aginst different instar larvae ofCulex pipiens molestus. The biocide “Bactimos”,Bacillus thuringiensis var.israelensis, was confirmed as pathogenic for mosquito larvae ofC. pipiens molestus. At dosage of 0.000125 mg/250 ml water, mortalities of 25, 98, and 97% were recorded for the 1st, 2nd and 3rd instar larvae after 24 hrs, respectively. Dosage of 0.008 mg/250 ml water proved to kill all types of instar larvae (100% mortality) after 24 hours. Water volumes ranging from 100 to 800 ml, containing 0.005 mg “Bactimos” per each were found to kill the 2nd and 4th instar larvae (90–100% mortality) with no significant differences. In conclusion, it is quite evident that the commerical bacterialbiocide “Bactimos” should be recommended as biomortality agent against mosquito larvae in Upper Egypt.     

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.     

Temporal changes in soil biochemical properties with seasons under rainfed land use systems in Shiwalik foothills of northwest India

The soil biochemical properties are sensitive to change in land use systems and seasons. The variations in soil management practices and soil moisture content affect the sustainability of the systems. To study the sustainability in lower Shiwalik, a total of 144 soil samples (0–0.15 m) were undertaken to monitor the changes in the soil biochemical properties under rainfed land use systems, i.e., agri-horticulture, agroforestry, cultivated and barren system and seasons, i.e., summer, rainy and winter. Among soil biochemical properties, soil microbial biomass carbon, soil microbial quotient, dehydrogenase activities, basal soil respiration, fluorescein diacetate and urease activities ranged from 77 to 122 μg g^?1, 0.023 to 0.027, 18.3 to 30.6 μg TPF g ^?1 h^?1, 13.2 to 22.7 μg CO₂-C g^?1 day^?1, 1.3 to 2.2 μg g^?1 and 5.83 to 6.38 μg NH₄-Ng^?1 h^?1, respectively. Among 15 soil properties, principal component analysis specified that four major soil properties, i.e., basal soil respiration, metabolic quotient, electrical conductivity and clay content contributed 73% of the soil quality index with contribution of 44, 13, 9 and 7%, respectively. Among seasons, the values for soil biochemical properties were higher in rainy season as compared to winter and summer season. In systems, agri-horticulture followed by agroforestry was the best systems in terms of sustainability in Shiwalik foothills of northwest India.

     

Effect of nitrogen fertilizer on biomass production and nodulation behavior of Pongamia pinnata Pierre seedlings under nursery conditions

At the seedling stage, a small amount of N is required to boost growth of leguminous plants. A pot experiment was conducted to observe the effect of N fertilizer on various growth parameters and nodulation behavior of Pongamia pinnata under nursery conditions. After the establishment of seedlings, four nitrogen treatments, 0, 40, 80 and 100 kg·ha^?1 N were applied in two equal splits. Monthly observations were taken for the morphological parameters viz. plant height, collar diameter, leaf number, root length, root shoot ratio, nodule number and weight per plant. Maximum plant height was recorded after application of N at 40 kg·ha^?1. Seasonally, the difference in collar diameter in rainy season was significantly higher than in winter or summer. However, more leaves were produced per plant at N-40 and N-100 treatments in winter and rainy seasons. Higher root length was recorded in rainy season than in winter or summer. Root biomass was higher than for stems or leaves. Seasonal effects of N-80 and N-40 treatments on leaf dry weight were significantly higher than for N-100 or N-0. Stem dry weight was higher at N-40 than at other treatments in winter and summer seasons. Root:shoot ratio was higher throughout winter to early summer. Nodule biomass was 2–3 times higher in rainy season compared to winter or summer. Maximum nodule number and biomass per plant were highest at N-40, followed by N-0, N-80 and N-100 treatments. New nodule formation started from June to the end of September. Maximum biomass per plant was recorded at N-40, followed by N-80, N-100 and N-0. Nitrogen treatment effect and seasonal behaviour interaction were not significant. Significantly higher numbers of nodules per plant were recorded in rainy season followed by summer and winter for all treatments. Higher nitrogen doses suppressed growth while lower doses promoted growth in Pongamia pinnata. Therefore, the lower nitrogen dose i.e., N-40 Kg·ha^?1 applied in two equal splits was suitable at the initial nursery stage for the increase in nodulation and biomass production.     

Impact of neem and chinaberry fruit extracts on the pest/parasitoid (Pieris rapae/Hyposoter ebeninus) interactions

A new technique was performed to simulate exposure of the host Pieris rapae larvae to both botanical treatment and the parasitoid Hyposoter eheninus in different sequences. It was found that: host larvae subjected to both parasitoid and 1?% neem treatment showed significant or insignificant reductions both in pupal formation as well as adult emergence percentages when treatment preceded or followed parasitism, respectively. Both neem treatments revealed significant prolongation in the development of unparasitized and parasitized larvae (on average 4 to 5 days delay), whereas chinaberry caused significant prolongation only among parasitized larvae (on average 2.7 days delay in egg-larval duration). Fate of parasitism among untreated hosts was found to be faster than among neem-treated ones. Parasitism percentages among 1 and 0.5?% neem-treated third instar host larvae held 7 days before parasitism reached 3 and 2 times that achieved among those reared on untreated diet for the same period, ­respectively. It was concluded that prolongation of the preferred target instars of the host, due to neem treatments, increased the chance for parasitism. Nevertheless, treatment with neem at the LC₅₀ level exhibited a great reduction in parasitoid progeny. However, a lower concentration (LC₂₅) could reasonably potentiate parasitism without drastic losses in parasitoid emergence.