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.     

Zum Auftreten der Robinien-Miniermotte,Phyllonorycter robiniella (Clem.) und der Ro?kastanien-Miniermotte,Cameraria ohridella Desch. & Dim. (Lep., Gracillariidae) in Südtirol

Zusammenfassung  An 2 Gracillariiden,Phyllonorycter robiniella undCameraria ohridella, wird gezeigt, wie rasch importierte Sch?dlinge sich ausbreiten k?nnen: Die RobinienblattmotteP. robinella wurde in Südtirol erstmals 1991 festgestellt und trat 1996 bereits in Massenbefall bei Brixen an Robinien auf.—Die Ro?kastanienminiermotteC. ohridella war hier erstmals 1992 im Pustertal bei Toblach festgestellt worden (Butin & Führer, 1994). Neueste Untersuchungen im Herbst 1997 zeigen, da? sie nun bereits im gesamten Eisacktal zwischen Franzensfeste und Bozen an Ro?kastanien (Aesculus hippocastanum) verbreitet ist (Tab. 1); hingegen wurde im Etschtal südlich und westlich von Bozen bisher noch kein Befall festgestellt.

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On the occurrence of the robinia-leafminer,Phyllonorycter robiniella (Clem.) and the horse-chestnut- leafminer,Cameraria ohridella Desch. et Dim. (Lep., Gracillariidae) in South Tyrol

The examples of two species of Gracillariidae,Phyllonorycter robiniella andCameraria ohridella, show how fast the expansion can take place: The robinia-leafminerP. robiniella was first noticed in South Tyrol in 1991 and an outbreak occured on False Acacias near Brixen, already in 1996.—The horsechestnut leafminerC. ohridella was first noticed in the Pusteria Valley near Toblach-Dobiacco, in 1992 (Butin & Führer, 1994). The latest research, of autumn 1997, shows that they are now distributed on Horse Chestnut Trees (Aesculus hippocastanum) in the whole Isarco Valley, between Fortezza and Bozen-Bolzano (Tab. 1), whereas in the Adige Valley at south and west of Bolzano no occurrence could be found as yet.

     

Integrated control of the solitary carpenter worm,Paropta paradoxa H.-Schaeff. (Lep., Cossidae) on fig trees in Egypt

According to the new trend of insect pests control in fruit orchards, biological in addition to mechanical control were evaluated for their efficiency on the reduction ofP. paradoxa population on fig trees during 1996, 1997 and 1998. Primary trials using the bacterial biopreparations of Delfin, Dipel and Bactospeine at the concentration of 200g/100 l. w. resulted in 81.8, 75.8 and 72.3% reduction of pest infestation, respectively. Pruning the infested branches, worming the larvae inside their tunnels and both mechanical treatments together along two successive years, reduced the infestation by 17.5, 47.4 and 57.9%, respectively. A control programme ofP. paradoxa was conducted using the techniques of pruning and worming besides spraying with bacterial insecticides at a rate of 200g/100 l.w. The performed mechanical and biological treatments together for one year gave 79.2–94.5% reduction of infestation, that reduction increased to 83.0–98.1% when these treatments were applied two years successively.     

Integrated control of the solitary carpenter worm,Paropta paradoxa H.-Schaeff. (Lep., Cossidae) on fig trees in Egypt

According to the new trend of insect pests control in fruit orchards, biological in addition to mechanical control were evaluated for their efficiency on the reduction ofP. paradoxa population on fig trees during 1996, 1997 and 1998. Primary trials using the bacterial biopreparations of Delfin, Dipel and Bactospeine at the concentration of 200g/100 l. w. resulted in 81.8, 75.8 and 72.3% reduction of pest infestation, respectively. Pruning the infested branches, worming the larvae inside their tunnels and both mechanical treatments together along two successive years, reduced the infestation by 17.5, 47.4 and 57.9%, respectively. A control programme ofP. paradoxa was conducted using the techniques of pruning and worming besides spraying with bacterial insecticides at a rate of 200g/100 l.w. The performed mechanical and biological treatments together for one year gave 79.2–94.5% reduction of infestation, that reduction increased to 83.0–98.1% when these treatments were applied two years successively.     

Zur Weiterentwicklung eines halbsynthetischen N?hrmediums fürIps typographus L.

Zusammenfassung  Das halbsynthetische N?hrmedium vonSimsek undFührer (1993) sowieSimsek (1995) wurde in bezug auf Handhabung und Inhaltsstoffe weiterentwickelt. Es eignet sich sehr gut als Ern?hrungssubstrat für Larven, Puppen und adulte K?fer. Ganze Generationszyklen lassen sich jedoch noch nicht reproduzierbar darauf züchten.

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Further development of a semiartificial diet forIps typographus L.

The semiartificial diet for the bark beetleIps typographus L. ofSimsek andFührer (1993) andSimsek (1995) was further developed in its handling and composition of the vitamin solution. The biological availability of the vitamins of the vitamin b-group was investigated. The diet is useful as rearing medium for larvae, pupae and adult beetles. But it is not possible by now to grow reproducibly a whole generation cycle on this diet.

     

转cry1Ab/cry2Aj、cry1Ab/vip3DA玉米对棉铃虫、甜菜夜蛾和斜纹夜蛾的抗虫性评价

为评估转cry1Ab/cry2Aj、cry1Ab/vip3DA玉米对棉铃虫Helicoverpa armigera(Hübner)、甜菜夜蛾Spodoptera exigua(Hübner)和斜纹夜蛾Prodenia litura(Fabricius)的抗虫性,在室内测定了3个转cry1Ab/cry2Aj玉米品系和1个转cry1Ab/vip3DA玉米品系对3种害虫幼虫存活和生长发育的影响,研究了该系列Bt玉米不同组织器官对害虫的杀虫活性和控制效果。结果显示,棉铃虫初孵幼虫取食各品系Bt玉米叶片96h后死亡率为87.50%~90.00%,取食花丝和雌穗的幼虫96h后几乎全部死亡;甜菜夜蛾初孵幼虫取食各品系Bt玉米叶片、花丝和雌穗168h后死亡率为22.50%~68.33%,幼虫的生长发育受到明显抑制,体重抑制率达85.00%~95.00%;斜纹夜蛾初孵幼虫取食各品系Bt玉米叶片、花丝和雌穗96 h后死亡率显著高于非转基因亲本对照,168h后幼虫死亡率达90.00%以上。研究表明,转cry1Ab/cry2Aj和cry1Ab/vip3DA玉米品系对棉铃虫和斜纹夜蛾的初孵幼虫表现出较好的抗性,可以作为转多基因抗虫玉米育种的备选材料。     

Die Verunkrautung neuangelegter mediterraner Weidetypen im Gebiet Mogod/Tunesien

Weed infestation of newly sown Mediterranean grassland at Mogod/Tunesia The reasons for the weed infestation of newly sown grassland in the humid north-west of Tunisia were examined with the help of plant sociological and soil investigations and the use of already available records on farm management. The variation of the weed infestation from year to year is very distinct. On the other hand weed infestation in the course of the year varies hardly from year to year. Weed infestation of the clover-grass pastures is clearly greater on sandy soils than on heavy soils. The reasons for this are due to the unsuitability of the sites, but in particular to a number of management mistakes. Weed growth has been encouraged through, among other things, the following: (1) the unfavourable distribution of rainfalls in 1970–71, 1972–73 and 1973–74; (2) grazing systems with high rates of stocking, short time allowed for grazing and longer rests; (3) careless pasture management on sites flooded in winter; (4) weed control with unsuited herbicides; (5) various pests and diseases which preferentially attack clover. The infestation of pastures used for cutting over a number of years with Festuca arundinacea (Schreb.) is not very pronounced and is decreasing markedly over the years due to the annual cutting in spring. After cutting a specific infestation of perennial weeds quickly develops. Suggestions are made as to the reduction of the weed infestation by keeping livestock constantly on the clover-grass pastures. der Vegetation bestimmt Ormenis praecox das Pflanzenkleid, stirbt aber im Februar ab. Danach werden alle Unkrauter durch die hohe Konkurrenzkraft des schnellwüchsigen Rohrschwingels fast vollständig unterdrückt. Der nachfolgende Schnitt im April trifft die im Bestand verbliebenen Unkräuter in der Blüte und bewirkt so eine abnehmende Verunkrautung der Flächen über die Jahre. Nach dem Schnitt allerdings verun-krauten die Stoppeln sehr einheitlich mil Cichorium intybus, Convolvulus arvensis L. und Cynodon dactylon.     

Application of some bacterial varieties ofBacillus thuringiensis and its bioproduct Delfin onSynanthedon myopaeformis Borkh. (Lep. Aegeriidae) in apple orchards

Field experiments were conducted using the biological agentBacillus thuringiensis to control the clearwing moth,Synanthedon myopaeformis (Lep. Aegeriidae) in apple orchards at Alexandria governorate during 1995, 1996 and 1997. Three bacterial varieties ofB. thuringiensis showed significant influence on the reduction of borer infestation. Four applications with the sporic concentration 12×10⁷ spores/ml of each ofB. th. var.kurstaki, B. th. var.alesti andB. th. var.thuringiensis induced 82.5, 51.1 and 42.1% reduction of infestation, respectively. Methods of application showed highly significant effect on infestation level. Sparying after scraping was the best method (80.0%, reduction) followed by painting after scraping (71.5%, reduction) then spraying alone (59.7%, reduction) or painting alone (43.0%, reduction). A control programme was carried out using three applications of the biomaterial, Delfin at the rate of 200 g/100 I.w. during mid-March, early June and mid-August resulted in 88.5–91.4% reduction of infestation.     

Impact of Parthenium hysterophorus on grazing land communities in north‐eastern Ethiopia

An investigation into the impact of Parthenium hysterophorus infestation was conducted in 2007 in the north‐eastern grazing lands of Ethiopia. Data on the above‐ground and seedbank species diversity were collected from five areas, each having sites with low, medium, or high levels of weed infestation. A total of 72 species was found in all areas. They were categorized into grass species (23), other species (48), or P. hysterophorus for ease of interpretation. A regression analysis showed a highly significant, but negative, relationship between the above‐ground species diversity and evenness with P. hysterophorus abundance. The mean cover abundance for the three infestation levels was 33.4% for P. hysterophorus, 41.0% for the grass species, and 26.5% for the other species. The most dominant grass species under all infestation levels were Cynodon dactylon, Urochloa panicoides, and Chloris gayana, while Andropogon abyssinicus and Eragrostis spp. were dominant under the low and medium infestation levels, respectively, and Hyparrhenia hirta was dominant under the low infestation level. Among the other species, Solanum nigrum was the most dominant under the low infestation level and Datura stramonium and Xanthium spp. were the most dominant under the medium and high infestation levels, respectively. The above‐ground dry biomass of P. hysterophorus increased between the low and high infestation levels, while that of the grass or other species reduced in the high, as compared to the low, infestation level. Although the grass species density decreased significantly with successive increases in the P. hysterophorus infestation level, no such trend could be seen for the other species. Within the soil seed bank, the viable seed density for the grass species, other species, and P. hysterophorus were 25.7, 5.8, and 68.5%, respectively. Similarly, the soil seed bank under the low‐, medium‐, and high‐infestation sites was dominated by P. hysterophorus, which contributed 25.1, 65.4, and 87.4% of the viable seed bank, respectively. Although the overall similarity between the above‐ground vegetation composition and the soil seed bank was low, it was similar at the low‐infested site. Thus, the invasion by P. hysterophorus was found to critically endanger the biodiversity of the grazing lands, particularly for the different grass and forbs species in the area. These changes might adversely affect not only future agriculture, but also food security, unless appropriate practises are developed and implemented for P. hysterophorus management.     

F?ngigkeit von differenziert bestückten Borkenk?ferpheromonfallen in einem nieders?chsischen Forstgebiet bei Hannover w?hrend der Jahre 1992 und 1993

Zusammenfassung  In den Jahren 1992 und 1993 wurden 24 schwarzeTheysohn-Schlitzfallen mit Kombinationen von synthetischen Borkenk?ferlockstoffen, Pheroprax, Chalcoprax, Linoprax und Cembrax, auf ihre F?ngigkeit getestet. Zum Vergleich wurden Fallen mit Einzelbestückung und Zweifachkombinationen von Pheroprax+Cembrax und Linoprax+Cembrax sowie zwei Fallen ohne Lockstoff in einem 24 ha gro?en Forstgebiet aufgestellt. Mit den Fallen wurde die Flugaktivit?t der angelockten Scolytiden ermittelt. Die erhaltenen Fangzahlen vonIps typographus, Pityogenes chalcographys, Xyloterus lineatus undX. domesticus wurden w?chentlich registriert und in Verbindung mit der unterschiedlichen Pheromonbestückung der Fallen diskutiert. Von den drei letztgenannten Arten wurde der Fang von M?nnchen und Weibchen getrennt bewertet. In einzeln mit Pheroprax bestückten Fallen fanden sich die meisten Buchdrucker pro Falle. Ihr Anteil nahm 1993 um 9% gegenüber dem Vorjahr zu. Für den Kupferstecher waren die vierfach kombinierten Pheromonfallen etwas f?ngiger als die einzeln mit Chalcoprax bestückten Fallen. AuchXyloterus-Arten bevorzugten die vierfach kombinierten Pheromonfallen gegenüber solchen, die nur Linoprax enthielten. Die Anzahl der gefangenen Ambrosiak?fer wurde im Verlauf von 5 Jahren stark reduziert. In beiden Untersuchungsjahren wurden neben den gezielt gek?derten Scolytiden 252 K?ferarten aus 49 Familien registriert, von denen 10 Arten eine Pheromonpr?ferenz erkennen lie?en. Der Beifang betrug j?hrlich 0,6–0,7% der Gesamtzahl an gefangenen K?fern. Zu 85–87% war der Kupferstecher am Gesamtfang beteiligt. Der Buchdrucker hatte einen Anteil von 11–14% an der Gesamtausbeute.

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In the years 1992 and 1993 blackTheysohn slit-traps were set up in a forest area near Hanover, Germany. The traps were baited with combinations of the synthetic bark beetle pheromones Pheroprax^?, Chalcoprax^?, Linoprax^?, and Cembrax^?. Their captivity was tested in comparison to singly baited and control traps without pheromone. Additionally, combinations of Pheroprax+Cembrax and Linoprax+Cembrax were tested. The captivity numbers obtained fromIps typographus, Pityogenes chalcographus, Xyloterus lineatus andX. domesticus were discussed in relation to the differently baited traps. In the latter three species, females and males were separated. The periods of flight activity of the four Scolytidae baited were ascertained for both years. Concerning the singly baited traps, Pheroprax captured the highest amount ofIps typographus per trap, its population increased 9% in 1993 related to that of 1992. ForP. chalcographus, the combination of the four pheromones resulted in a little higher number of individuals than in singly baited traps.Xyloterus lineatus preferred the four-pheromone combination, in which Linoprax was present showing a synergistic effect of baiting. In contrary, the baiting ofX. domesticus was lower by the combined pheromones than by Linoprax alone. The latter was found in lower numbers thanX. lineatus. The trapped amounts of both Xyloterus species were continuously reduced throughout the years 1989 to 1993. The Coleoptera species, not specially trapped, amounted yearly to 0.6–0.7% of the collected individuals.P. chalcographus was collected to 85–87%, andIps typographus to 11–14% of the total amount of Coleoptera trapped.

     

Influence of altitude on adult emergence and dynamics ofKaltenbachiola strobi (Winnertz) (Diptera: Cecidomyiidae) populations and its parasites in the Tatra National Park, Poland

A field study onKaltenbachiola strobi (Winnertz) (Diptera: Cecidomyiidae), was carried out between 1987 and 1993 in the highest mountain range in the Western Carpathians located within the Tatra National Park, in southern Poland. Rearing and analysis of 5 780 cones ofPicea abies (L.)Karst., collected from trees growing at different altitudes, yielded 30,478 individuals ofKaltenbachiola strobi, which infested 89.10% of the cones. In case of 29.81% of cones there were more than 20 larvae ofK. strobi per cone. It was shown thatK. strobi in the Tatra Mts. is more abundant in spruce stands of the upper mountain forest zone. Significant connections between the time of cone infestation byK. strobi and its parasitoids and characteristic phenophases in spruce foliage and cone development, and also the development of selected vegetation of the forest floor at different heights above sea level were determined. It was shown that the population dynamics ofK. strobi had tendency to alternate the increase and decrease in numbers every two years. It was also discovered that every two years spruce cones were inhabited by the population ofK. strobi with increased percentage of individuals having prolonged diapause. In total, the parasitoids reduced the population ofK. strobi by about 16–22.63%. Parasitism ofK. strobi in the lower mountain forest zone was higher than in the upper zone.Triplatygaster contorticornis Ratz. (Hymenoptera: Platygasteridae),Torymus azureus Boheman (Hymenoptera: Torymidae) andTetrastichus strobilanae Ratz. (Hymenoptera: Eulophidae) were most effiecient in reduction of the population ofK. strobi, and in the lower mountain forest zoneT. azureus was the dominant parasitoid species, while in the upper zoneT. contorticornis andT. strobilanae. It was shown that a considerable part of the populations ofT. azureus, T. contorticornis andT. strobilanae have their diapause prolonged and highly synchronized with the diapause of their host.     

Zur aktuellen Situation des Hausrattenbefalls (Rattus rattus [L.]) in der Stadt Magdeburg

Zusammenfassung  Die aktuelle Befallsituation (1998/1999) bei den Hausratten-best?nden (Rattus rattus [L.]) in der Stadt Magdeburg wurde in Zusammenarbeit mit Sch?dlingsbek?mpfern und Objektbesitzern ermittelt. Dabei wurden 10 Objekte bekannt, in denen der Nager nachgewiesen werden konnte. Es handelte sich um Kornmühlen, Silos und Lebensmittelgro?betriebe. In mehreren dieser Geb?ude siedelte die Dachratte seit Jahrzehnten. Bek?mpfungsaktionen verliefen schon immer erfolglos. Zur Zeit wird aus Kostengründen kein Vorkommen mit Konsequenz bek?mpft.

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On the current situation of infestation of the City of Magdeburg with the house rat (Rattus rattus [L.]). In the City of Magdeburg, the current incidence (1998/99) of the house rat (Rattus rattus [L.]) was studied by way of cooperation with those concerned (millers, storekeepers, warehous keepers) as well as business and persons involved in pest control. The ‘blue attic rat’ was detected on ten premises or properties (grain mills, silos, big food companies). Many of the buildings have been infested with the house rat for years. Frequently, control action has failed to turn out successful and hence, not taken at all because of the high cost of eradication involved. Referring to the house rat re-appearing or detected after control action, it was difficult to decide whether it was a re-infestation or just remainders of the previous population of the buildings.

     

Laboratory evaluation and field application of bacterial and fungal insecticides on the citrus flower moth,Prays citri miller (Lep., hyponomeutidae) in lime orchards in Egypt

The efficacy of two commercial products of Bactospeine and Bio-fly onPrays citri of lime trees was studied under laboratory and field conditions throughout the two seasons of 1996 and 1997. Laboratory results indicated that the pathogenic effect of Bactospeine,Bacillus thuringiensis (Berliner) was higher than that of Bio-fly,Beauveria bassiana in spite of the latter was applied with higher doses. Bactospeine at the rate (2 cc/1 l.w.) effected on the larvae more than on the adults, that treatment reduced no. of eggs/female by 81.70% and decreased the larval infestation by 90.08%. Bio-fly at the highest concentration (4 cc/1 l.w.) reduced the infestation with the eggs, the larvae and the pupae by 65.83%, 68.45% and 72.55%, respectively. Advanced effects of bacterial and fungal treatments on the final reduction rates ofP. citri infestation were recorded. Field applications revealed that two sprays with Bactospeine or Bio-fly gave good control ofP. citri more than one spray. Bactospeine at the rate (2 cc/1 l.w.) and Biofly at the rate (4 cc/1 l.w.) reduced the infestation by (89.82–93.43%) and (76.32–78.83%), respectively. In all cases, higher doses of bioinsecticides produced potentiation effects of infestation reduction. It is recommended that two sprays of Bactospeine at a rate (2cc/1 l.w.) are adequate effective to reduce the population of P. citri in lime orchards during the main flowering period of trees without need of chemical insecticides. An erratum to this article is available at .     

褐飞虱与白背飞虱为害诱导水稻防御反应的比较

为探究2种稻飞虱——褐飞虱Nilaparvata lugens(St?l)和白背飞虱Sogatella furcifera(Horváth)诱导的水稻防御反应差异,于室内测定了水稻在分别受褐飞虱或白背飞虱产卵雌成虫为害时,其茉莉酸、水杨酸、乙烯、H_2O_2以及挥发物含量的变化。结果表明,尽管褐飞虱和白背飞虱产卵雌成虫的为害均可以诱导水稻茉莉酸、水杨酸、乙烯和H_2O_2等防御相关信号分子以及一些水稻挥发物含量的增加,但是二者的诱导作用存在差异。水稻在受白背飞虱产卵雌成虫为害时,茉莉酸的含量在3 h时就显著升高,12 h时含量达到最高;而受褐飞虱产卵雌成虫为害时,6 h时茉莉酸含量才显著升高,72 h时含量达最高;并且在2种稻飞虱为害的3～48 h内,白背飞虱为害诱导的茉莉酸含量始终显著高于褐飞虱为害诱导的。水稻受白背飞虱产卵雌成虫为害24 h后诱导的水杨酸含量、为害48 h后诱导的乙烯含量、为害72 h后诱导的H_2O_2含量及为害24 h后诱导的挥发物释放量分别是褐飞虱产卵雌成虫为害诱导的1.28、1.45、4.10和1.77倍。表明水稻能识别褐飞虱和白背飞虱的为害,从而做出针对害虫种类特异性的防御反应;并且水稻对白背飞虱产卵雌成虫为害所做出的防御反应比对褐飞虱的更强烈。     

黄淮海地区不同种植结构下点蜂缘蝽的发生规律

为明确大豆-玉米带状间作种植模式对点蜂缘蝽Riptortus pedestris发生规律的影响,2023年在山东省大豆单作田中进行诱捕效果试验,筛选诱捕效果最好的诱捕器对黄淮海地区山东、河南和安徽3个省6个市不同种植模式下点蜂缘蝽的发生动态进行监测。结果显示,风叶型诱捕器对点蜂缘蝽的诱捕效果最佳。在大豆单作田内点蜂缘蝽的发生高峰期为7月中旬—8月中旬,此时大豆正值盛花-始荚期。在大豆-玉米带状间作田内点蜂缘蝽的发生动态与大豆单作田的无明显差异,但点蜂缘蝽发生数量及高峰期发生时间可能与杀虫剂的施用时间和次数密切相关。     

Seasonal abundance of different stages of the citrus thrips,Scirtothrips aurantii, on two mango cultivars in South Africa

The citrus thrips,Scirtothrips aurantii Faure (Thysanoptera: Thripidae), is a pest of mango in South Africa. The aim of the study was to monitor the different stages ofS. aurantii in mango orchards throughout the year. Populations ofS. aurantii were monitored using different methods,i.e., yellow sticky traps, dispersal/emergence traps, counts on fruit and in flowers. Eggs and emergence holes on the new leaves were recorded. The number of adults increased at the end of flowering (September) and remained at high levels until fruiting (November). Low numbers were present from May to August. Much higher population levels were present during 1995/96 than during the 1996/97 season. There was higher infestation present on the cultivar ‘Sensation’ than on ‘Zill’.S. aurantii was present on the fruit for only a short period (less than 10 weeks) during the season and the population was maintained on flush that was present throughout the year.     

Seasonal Dynamics of Metabolic Mechanisms Mediating Pyrethroid Resistance in Helicoverpa armigera in Central India

Very high cypermethrin and fenvalerate resistance frequencies were recorded in Helicoverpa armigera (Hübner) populations in central India during the 1993–94, 1994–95 and 1995–96 cropping seasons. Synergism assays and biochemical analyses of detoxification enzyme levels indicated that mono-oxygenases and esterases were important metabolic mechanisms mediating pyrethroid resistance. Piperonyl butoxide- (PBO) and profenofos-suppressible pyrethroid resistance were correlated with enhanced levels of cytochrome P450 and general esterases respectively. Enzyme assay data indicated that high cytochrome P450 levels generally coincided with low esterase activity and vice versa. Similarly, synergist bioassays showed that PBO-insensitive resistance was frequently associated with profenofos-sensitive resistance and vice versa. Oxidase- and esterase-mediated mechanisms evidently alternated in a reciprocal manner, with perceptible shifts in relative importance occurring during mid-October in all three seasons and in late January in 1995. Apart from metabolic mechanisms, a synergist-insensitive resistance mechanism (believed to be nerve insensitivity), accounted for an average of 51, 30 and 28% of cypermethrin resistance during the 1993–94, 1994–95 and 1995–96 seasons respectively. © 1997 SCI.     

敲除OsLRR-RLK18基因提高水稻对褐飞虱的抗性

为明确富亮氨酸重复类受体蛋白激酶（leucine-rich repeat receptor-like kinase,LRR-RLK）编码基因OsLRR-RLK18在调控水稻对褐飞虱Nilaparvata lugens防御中的作用及机理,以野生型水稻品系、OsLRR-RLK18基因敲除纯合水稻品系为研究对象,测定不同水稻品系的株高和根长、不同水稻品系对褐飞虱生物学参数的影响及褐飞虱为害后不同水稻品系中防御信号分子含量和防御化合物含量。结果显示,敲除OsLRR-RLK18基因后水稻株高和根长降低,褐飞虱为害后期诱导的茉莉酸、茉莉酸-异亮氨酸和脱落酸含量显著增加,但水稻组成型（未受褐飞虱为害）和为害早期的水杨酸和过氧化氢含量降低,引起水稻多种挥发物组分释放量增加,木质素、对香豆酰腐胺及樱桃苷、刺苞菊苷和大波斯菊苷3种类黄酮含量下降,最终导致褐飞虱卵孵化率和产卵量显著降低。表明OsLRR-RLK18基因参与了水稻对褐飞虱为害的防御反应,在调控水稻对褐飞虱的抗性中发挥着一定作用。     

Assessment of the spread of chestnut ink disease using remote sensing and geostatistical methods

Chestnut ink disease, caused by Phytophthora cinnamomi and P. cambivora, is responsible for important economic losses and limits the establishment of new chestnut (Castanea sativa) groves in Portugal. Although the differences in soil properties and in cropping practices affect ink severity, the regional spread of disease is not known. Data for monitoring C. sativa decline were obtained by using field surveys and Small Format Aerial Photography (SFAP), a reliable tool which provides large-scale imagery obtained at low altitude. Visible colour and near-infrared images were obtained with different cameras with an average ground resolution of 22, 14 and 39 cm. The spatial distribution of ink disease in northern Portugal for the years 1995–2004 was estimated through a geostatistical method, and the estimation of precision was determined. From 1995–2002, the chestnut population in the study area increased by 18.5% due to new orchard plantations. After 2002 the population decreased because the new plantations were not sufficient to recover the number of dead chestnut trees, killed mostly by ink disease. The directional semivariograms indicated anisotropy with a greater disease spread in the NE–SW direction. This direction corresponds to site areas at the same altitude, where soil tillage and human mobility are higher.     

Types of bark beetle (Coleoptera: Scolytidae) infestation in spruce forest stands affected by air pollution, bark beetle outbreak and honey fungus (Armillaria mellea)

583 spruce stands in an area affected by air pollution and bark beetle outbreak in Eastern Slovakia were studied in 1996. According to bark beetle infestation of dominant and codominant trees, stands were classified into following types of spruce stand decline:Ips typographus-A,Ips typographus-B,Polygraphus poligraphus, I. typographus/P. poligraphus—A,I. typographus/P. poligraphus—B. The presence of attacked trees in forest edges, bark beetle spots and forest interior was the key important factor for the classification. Data from forest inventory and forest management evidence together with data on types of spruce stands decline were used in further analyses. Results shows that the distribution of forest stands classified into different types or uninfested stands is related mainly to host size and site quality. The percentage of spruce, exposition of stands and stand density showed significant effects. The mechanisms of spreading of studied bark beetle outbreak could be explained by direct effects of stress of trees caused by an abrupt increase of level of solar irradiation and by weakening of trees by the honey fungus.